Pathophys Neuro

This patient's biopsy is consistent with meningioma, which is characterized by eosininophilic spindled-cells forming whorled pattern growth that form syncytial nest, which may calcified forming psamomma bodies. Other tumors with psammoma bodies are mesothelioma, papillary thyroid cancer, and papillary serous carcinoma of the ovary and endometrium. -Meningiomas are well circumscribed and are typically benign. The are attached to the dura mater usually around the falcine (mid sagittal), parasaggital and lateral convexity of the brain. -Clinical presentations are caused by space occupying lesion compressing on the adjacent cerebral cortex. Patients often develops headache, vomiting and nausea from increase intracranial pressure (elevates when lying done) that worsens during periods of recumbency and/or sleep. -Glioblastoma is a highly malignant primary brain tumor that are usually found within the white mater of the cerebral hemisphere with potential to cross hemisphere and affect the opposite side causing the characteristic "butterfly glioma" appearance. The characteristic histopathology morphology are hypercellular atypical astrocytes bordering region of necrosis, giving a pseudopalasading apperance. -Schwannomas are tumors of the schwann cell outside of the brain. Usually appearing at the cerebellopontine junction affecting CN VIII causing acoustic neuropathy. Microscopy shows spindled cells with palisading nuclei arranged around a nuclear free zone called Verocay bodies composed of eosionophilic core. -Oligodrendroglioma typically involves the white mater of the cerebrum with highest prevalence occurring in frontal lobe.. It has the monotonous appearing "fried egg" (Leggo my Eggo) appearance cells with round nuclei and clear cytoplasm. There are often calcification and with capillary growth resembling "chicken-wire" pattern. These tumors are relatively rare and are slow growing. -Prolactinoma is the most common pituitary adenoma. It often impinges the optic chiasm causing bitemporal heminopsia. Hyper or hypopituitarism are often sequelae. -Adanomatous craniopharyngioma is the most common benign suprasellar tumors in children. Cell origin is from the remanants of Rathke pouch. Microscopy will show palisading squamous epithelium appearing as cords/nest surrounding areas of lamellar "wet" keratin. Calcification is common and has tooth enamel like appearance. It often arises at the optic chiasm causing misdiagnosis of pituitary adenoma. -Ependymoma are paraventricular usually arsises at the fourth ventricle causing obstructive hydrocephalus. Histology shows cells containing rod-shaped blepharoplasts (basil ciliary bodies) found near nucleus that form perivascular rosettes. -Medulloblastoma is a highly malignant cerebellar tumor. Microscopy shows Homer-Wright rosettes formed by small blue cells. -Polycytic astrocytoma is a benign tumor that is most often found in the posterior fossa (e.g. cerebellum). Histology has hairlike processes called Rosenthal fibers (eosinophilic granular bodies and elongated corkscrew fibers).

A 45 year old woman presents to the emergency room after losing consciousness with rhythmic movements of limb followed by a period of confusion. The patient had mild daily headaches associated with nausea over the past 2 years. The headaches worsen at night and sometimes wake her up from her sleep. The patient denies head trauma, weakness, numbness, visual changes or difficulty speaking or swallowing. She does not drink alcohol or do illicit drugs. Intracranial mass was observed in MRI and biopsy shows pasomomma bodies and spindle cells concentrically arranged in a whorled pattern. What is your diagnosis? Glioblastoma Meningioma Schwannoma Oligodendroglioma Pituitary adenoma Adanomatous craniopharyngioma Ependymoma Medulloblastoma Polycystic astrocytoma

Von Hippel Lindau is an AD inherited disorder where patients have hemangioblastoma in the eye and/or cerebellum, as well as congenital cysts and/or neoplasms in kidney, liver and pancreas. Patients will also have an increase risk of renal cell carcinoma. Von Recklinghausen's aka NF1 is an inherited peripheral nervous system tumor. Patients develop neurofibromas, optic nerve gliomas, lisch nodule and cafe-au lait spots. No kidney involvement NF-2 is an AD nervous system tumor syndrome. Patients has increase risk of getting schwannomas and multiple meningomas. No kidney involvement. Sturge-Webeer Syndrome (encephalotrigeminal angiomatosis) is a rare neurocutaneous disorder characterized by cutaneous angiomas as well as leptomeningeal angiomas. Skin involvement is usually around V1 and V2. This condition is associated with mental retardation, seizure, hemiplegia and skull radioopacities (characteristic tram track appearance). Tuberous sclerosis may involve the kidney cysts and CNS lesion, however it is not angiomatous but as subependymal and cortical harmatomas. Patients can also develop angiomyolipomas and cardiac rhabdomyomas. Seizure is the major complications. Osler Weber Rendu syndrome is an AD congenital telangiectasia. Rupture may cause epistaxis, hematuria and IG bleeding.

MRI shows angiomatous lesion in the cerebellum. There is also right cystic mass in the kidney. The differential diagnosis must include what? Von Recklinghausen's disease NF-2 Von-Hippel-Lindau disease Sturge-Weber syndrome Tuberous sclerosis Osler-Weber-Rendu syndrome.

The median nerve travels between the flexor digitorum superfiicalis and flexor digitorum profundus. The ulnar nerve passes between the medial epicondyle of the humerus and olecranon. It then travels towards the Guyon canal coursing between the flexor carpi ulnaris and flexor digitorum profundus. The musculocutaneous nerve travels between the bicep brachii and the coracobrachialis. The nerve that travels between the supinator muscle and head of radius is your radial nerve.

Patient has weakness upon flexion of finger especially the first three digits, weakness of wrist flexion and diminished sensation over the first three fingers. Between which of these structures does it pass? -the biceps and coracobrachialis -flexor carpi ulnaris and flexor digitorum profundus -flexor digitorum superficialis and flexor digitorum profundus -olecranon and medial epicondyle of the humerus -supinator muscle and head of radius.

This patient is presenting with non-pupil sparing third nerve palsy secondary to aneurysm compressing the RIGHT PCA. It is important to remember that CN3 courses between the R PCA and superior cerebellar artery as it leaves the midbrain. Patient has chronic HTN and smoking habits which are risk factors for developing intracranial aneurysms. CN3 is a pure motor nerve carrying both general somatic efferent (GSE) and general visceral parasympathetic efferent (GVE) neurons. -GVE fibers are more peripherally located at the surface and they are in charge of the efferent limp of the pupillary light reflex and near vision. Because of the location, they are more susceptible to compression (e.g. aneurysms and tumors). -GSE fibers course within the interior portion of CN3 and supply innervation to the muscles involving in eye movement (e.g. superior rectus, inferior rectus, medial rectus, inferior oblique and levator palpebrae superioris). Because of their location, they are more susceptible to ischemic injury (e.g. small vessels disease from DM). The basilar artery is formed by two vertebral arteries. Lesion to this vessel normally doesn't not show non-pupil-sparing CN III palsy. The left PCA would show all of these symptoms but on the left side. Superior cerebellar arteries are branches of the basilar right before it bifurcation into the posterior cerebral artery. An aneurysm will also have the same presentation (e.g. non-pupil-CN3 palsy on the ipsilateral side). If this was left superior cerebellar artery, then it would be correct. AICA are branches from the basilar arteries. Lesion will cause lateral inferior pontine syndrome with CN VII and CN VIII. Also contralateral lost of pain and temperature sensation of the face, as well as Horner's and cerebellar symptoms.

A 55 right handed man shows up to the emergency room complaining of recent onset of severe headache around the right frontal orbital area and diplopia. Past medical history shows that he has poorly controlled HTN and is a chronic tobacco smoker. Patient is awake, alert and oriented and follows both simple and complex command. Testing of cranial nerves reveal intact bilateral visual acuity. Visual field and optic fundi is normal. Patient has aniscoria with the right pupil being dilated and non-reactive to both light and accommodation. He has evidence of horizontal and vertical binocular diplopia. The right eye is down and out with ptosis. The rest of the neurological examination is unremarkable. CT angiography shows large aneurysm in the posterior fossa. Which of the following blood vessel is the aneurysm most likely located at? Basilar artery Left PCA Right PCA Right superior cerebellar artery AICA

-Pyramidal neurons (upper motor neuron) in layer V of the primary motor cortex (Broadmann's area 4) located in the dorsal portion of the frontal lobe anterior to the wall of the central sulcus, travels through the posterior limb of the internal capsule passes the cerebral peduncle into the brain stem and the medulla. -Here they form two prominences call the pyramids of the medulla where the neurons decussate to the contralateral side and enter the spinal tract forming the lateral cortical spinal tract where they would synapse with the efferent lower motor neuron at the anterior horn.

Explain the cortical spinal tract and how you move

Essential tremor - family history and appears at rest and movements (hands, head, voice, ect). -Treatment: beta-blockers (propranolol), primidone (anticonvulsant), clonazepem and alcohol (often self medicated). Resting tremor - associated with Parkinson where it goes away with voluntary movement. Intention tremore - associated with cerebellum where it will appears only with voluntary movement.

What are the differences between essential, resting and intention tremors,

The inability to do rapid repeating movements. -Upper Ext.: Pronation and supination test or demonstrate movement of turning a doorknob or screwing in a light bulb. -Lower Ext.: Ask patient to tap your hand as quickly as possible with the ball of each foot in turn. -Speech: Ask patient to repeat syllables such as (pe, te, ke and phe); variation, excess loudness, and irregular articular breakdown are signs of dysdiadochoniesease

What is dysdiadochokinesis? Test?

It literally means wrong length use to describe a type of ataxia where patient cannot judge distance or scare. It is a lack of coordination of movement typified by the undershoot or overshoot of intended position with the hand, arm, leg or eye. Cerebellar modulates movements and aid in the coordination and balance. -It is supplied by AICA, PICA and SCA. Lateral lesions: -Voluntary movement of extremities. Propensity to fall toward injured (ipsilateral) side. Medial Lesions: involving midline structures (vermal cortex, fastigial nuclei) and/or Flocculonodular lobe: 1) Truncal ataxia (wide-based cerebellar gait) 2) Nystagmus 3) Head tilting. 4) Generally midline lesions result in bilateral motor deficits affecting axial and proximal limb musculature. Tests: 1) Make the patient touch your finger. Normally you can do this repeated with eyes closed, but in cerebellar lesion they tend to overshoot or undershoot. 2) Heel to toe text

What is dysmetria? What lesion can give you this? How would you test?

Guillain-Barre is the most common type of acute inflammatory demyelinating polyradiculopathy. It is characterized by segmental demyelination with inflammatory infiltrate in the endoneurium. -50% of cases have facial paralysis (Bell's palsy). -May cause autonomic dysregulation (e.g., cardiac irregularities, hypertension, hypotension) or sensory abnormalities. All patients survive, the majority recover completely after weeks to months. Respiratory support in critical until recovery. Additional treatments include plasmapheresis and immunoglobulins. -Werdnig-Hoffman syndrome is another name for poliomyelitis and spinal muscular atrophy characterized by a LMN lesion d/t destruction of anterior horns. Patient will have flaccid paralysis, areflexia, muscle atrophy and fasciculation (aka "floppy child" syndrome). -Subacute combined myelopathy is cause vitamin B12 deficiency, which is involved in fatty acid and myelin synthesis. Patient will present with truncal ataxia, wide unsteady gait, lost of proprioception/light touch/vibration, UMN lesion (e.g. spinocerebellar tract, lateral corticospinal tract and dorsal column dysfunction). -Beri Beri (thiamine deficiency) can cause demyelination but no perineural inflammation will be present. It is often associated with pain and paraesthesia. Most commonly involve the lower limbs. -Acute disseminated (postinfectious) encephalopmyelitis is a multifocal periventricular and demylination after infection (commonly seen with measles or VZV) or certain vaccinations (e.g., rabies, small pox). -Charcot-Marie-Tooth disease (AKA hereditary motor and sensory neuropathy (HMSN)) is a group of progressive hereditary (AD) nerve disorder related to defective production of protein involved in the structure and function of peripheral nerves or the myelin sheath. Associated with scoliosis and foot deformities (high or flat arches). -Krabbe disease (AR) is a lysosomal storage defect from the lack of galactocerebrosidase, which can accumulate along with psychosine and destroy the myelin sheath. Clinical findings include peripheral neuropathy, developmental delay, optic atrophy and globoid cells. -Metachormatic leukodystrophy (AR) is another lysosomal storage disease cause be deficiency in arylsulfatase A. Accumulation of sulfatides can impair production and destruction of myelin sheath. Clinical findings include central/peripheral dymelination with ataxia, dementia. -Progressive multifocal leukoenecephalopathy is d/t destruction of oligodendrocytes. Associated with JC virus and of course AIDS (reactivation of laten viral infection). Rapidly progressive, high mortality. INcrease risk with natalizumab and rituximab.

27 year old females comes in on a wheelchair complaining she cannot move her face or breath normally. Her facial paralysis started this morning, while her breathing problems started 2 days ago. She cannot walk for the past 7 days. She She denies trauma, fever, headache, confusion, nausea/vomiting, vision and hearing problems. She had a minor cold 2 weeks ago. Family, social and sexual history are all unremarkable. Her BP is 100/80, HR 100, RR 5 and Temp is 99. CSF shows increase protein with normal WBC and RBC. PE shows no reflex in S1 and L4. Mild papilledema. She was given respiratory support in addition to IV immunoglobulins. Which of the following does she most likely have? -Acute inflammatory demyelinating polyradiculopathy -Subacute combined myelopathy -Acute disseminated encephalomyelitis -Werdnig-Hoffman syndrome -Beri beri -Charcot-Marie-Tooth disease -Krabbe disease -Metachromatic leukodystrophy -Progressive multifocal leukoencephalopathy

Important structures in the frontal lobes are the motor cortex, Broca's, frontal eye field and prefrontal cortex. -Lesions to the prefrontal cortex will cause inappropriate behavior, impaired judgment and poor problem solving skills. Incontinence and gait disturbance may also be seen. Frontotemporal dementia (AKA Pick's disease) is characterized by degeneration of the frontal lobe that will eventually involve the temporal lobe. Characteristic symptoms are: -Early personality and behavior changes (eg. disinhibition, social inappropriateness, apathy, compulsive behaviors) -Altered speech pattern (paucity of speech and repeated phrase) -Later stage will cause neurocognitive deficits (dementia, note to differentiate from Alzheimer's which are associated with early short term memory deficit) Pick's Vs. Alzheimers Macroscopic examinations: -Pick's is associated with pronounced frontal and temporal atrophy. -Alzheimers is associated with mild-moderate generalized atrophy. Onset: -Picks is 50-60 -Alzheimers is 60-70 to older. Microscopic features: -Pick's is associated with early neuronal loss in the frontal/temporal lobes. *Picks bodies* which are cytoplasmic inclusion of microtubule associated tau protein. -Alzheimer's is associated with initial neuronal loss in the temporal/parietal lobes. It has neural fibrillary tangle and amyloid plagues. Initial symptoms: -Pick's is associated with personality changes -Alzheimer is associated with recent memory loss. Genetic: -Pick's AD -Alzheimer is involved with APP gene on chromosome 21 and apoE4. -The caudate nucleus is one of the structures of the basal ganglia. It is separated from the lentiform nucleus (putamen and globus pallidus) by the internal capsule. The caudate nucleus and the putamen form the dorsal striatum, which regulates voluntary movements. -Huntington causes degeneration of the caudate nucleus (atrophy) and presents with choreiform movement, psychiatric symptoms (irritability, depression) and dementia. -The hippocampus is part of the limbic system located on the bottom of the cerebral cortex in the medial temporal lobe. It is in charge of forming new memories, thus patients with hippocampus lesion with have anterograde amnesia. The hippocampus is the first part affected in Alzheimer. -The parietal cortex plays an important role in integrating sensory information. Lesion to the dominant inferior parietal lobule will result in Gerstmann syndrome (right/left confusion, dysgraphia (can't write), dyscalculia and finger agnosia). -Substantia nigra is located in the midbrain and contains dopaminergic neurons. Axons project to the striatum to regulate voluntary movement. Depletion of dopamine in the substantia nigra is the etiology for Parkinson where patients will present with resting tremor, bradydyskinesia (slowness of movement) and rigidity. Dementia and subsequent behavior issues will present in the later stage of the illness. -The subthalamic nucleus is part of the basal ganglia. It utilizes glutamate NTs and sends axons to the globus pallidus. Lesion will cause hemiballismus (involuntary flinging movements of the extremities on the contralateral side of the lesion.

54 year old man is brought to the doctor by his daughter. She says that her father has been acting strange for the last 2 years. He makes inappropriate sexual jokes, has little regards for social rules, irritable and borderline aggressive at times. Patient denies his personality is not different from normal. When talking to the patient, the physician notices that he has minimal verbal output and repeats "it is what it is" when asked questions about his strange behavior. On physical examination, the patient seems unkempt but everything else is pretty much unremarkable. This patient most likely have a condition affecting what part of the brain? a. caudate nucleus b. frontal cortex c. hippocampus d. parietal cortex e. substantia nigra f. subthalamic nucleus

The ulnar nerve comes from the medial cord of the brachial plexus. It courses posteriomedially in the upper arm and enters the anterior compartment of the forearm by going underneath the medial epicondyle. At the wrist it enters the Guyon canal (between hamate and pisiform). -It provides sensation over the medial 1 and half digits (i.e. the pink and half of the ring finger) and the hypothenar eminence. -It innervates muscle responsible for flexion and adduction of the wrist, flexion at the MCP (medial 1.5 digits) and extension at the IP (medial 1.5 digits). -Patient often present with an ulnar claw upon extension of the fingers characterized by extension of the first 3 digits and flexion of the IP joint and extension of the MCP joint of the pinky and ring fingers. -Wrist abduction is controlled by the median nerve along with wrist flexion, and flexion of the first 3 digits at the MCP and extension of the same digits at ICP. It provides sensation to the first three fingers and skin over thenar eminence. Patients with median nerve palsy will present with the characteristic "Preacher's hand aka Benedict's hand" up making a fist. The 4th and 5th digits are flexed, while the first three fingers are extended (d/t unopposed action of the radial nerve). If both the median and ulnar nerves are damaged, patient will present with the characteristic "Simian Hand" where the hand and fingers extended similar to that of a beggar hand. -Patient with musculocutaneous lesion will present with inability to flex the forearm at the elbow joint and lost of sensation to the lateral part of the forhand. -Wrist extension is the job of the radial nerve. Patients will have lost of sensation over the posterior part of the arm and forearm, the posteriolateral portion of the hand and the dorsal part of the thumb. Patient will present with the characteristic wrist drop.

55 year old man complains of weakness in right hand with pins/needles sensation. Denies head, neck or upper extremities injury. Patient has been smoking a pack a day for 30 years. On physical examination, he has decreased feeling to the 5th digit. What disability will most likely be present in this patient? -wrist adduction -wrist abduction -wrist extension -elbow flexion

Patient symptoms are suggestive of left MCA lesion because it supplies the left anterior lateral surface of the brain which includes the left motor/sensory cortex of the upper limb, trunk and face and the language centers Broca's (frontal) and Werneke's (temporal), assuming that this patient is left dominant. Thus a patient with left MCA lesion will have contralateral (right) weakness and numbness of the face and upper limb. He has Broca's aphasia thus he cannot speak but is able to understand language. This is not right MCA lesion because he has Broca's aphasia and you would expect left sided weakness and numbness to face/upper limb, not right. In addition, patient with non-dominant lesion to these areas will have perceptual deficit such as hemispatial neglect, anosognosia, apraxia and spatial disorganization. Occlusion of the left ACA will lead to right sided weakness/numbness of the lower limb, where urinary incontinence and primitive reflex may be present. Occlusion of AICA will lateral inferior pontine syndrome. Patient will have contralateral loss of pain and temperature sensation accompanied by ipsilateral deficits in CN V and CN VIII, Horner's syndrome and cerebellar symptoms. Occlusion of PICA will lead to lateral medullary (Wallenberg) syndrome characterized by contralateral loss of pain and sensation, ipsilateral deficits to CN V, VIII, IX, X, XI and Horner's syndrome.

66 year old caucasian male with history of a-fib develops right sided weakness and numbness on the face, trunk and upper limbs. He understands everything that is said to him but cannot speak. An embolus would most occlude which of the following arteries that would give patient's symptoms. Right MCA Left ACA Left MCA AICA Post. Cerebellar A.

The posterior cerebral arteries, part of the posterior circulation, comes from the basilar at the level of pontomesencephalic junction. It supplies CN III and CNIV and other structures in the midbrain. It also supplies the thalamus, medial temporal lobe, splenium of the corpus callosum, parahippocampus gyrus, fusiform gyrus and occipital lobe. The most common finding of a PCA lesion is contralateral hemianopia, often with macular sparing (supply by MCA). Involvement of the lateral thalamus often causes contralateral paresthesia and numbness affecting face, trunk and limb. MCA is part of the anterior circulation along with the Lecticulostirate striate artery (branches of MCA) and ACA. This artery supplies sensory/motor cortex of the face and upper limb. Broca's (frontal) and Wernecke's (temporal) speech areas and the frontal eye field. It also gives small penetrating arteries that supplies the basal ganglia and the internal capsule. If this patients right MCA is compromised, you would not expect macular sparing. If left MCA is compromised, speech will be affected. If right MCA is compromised you would have perceptual deficit (hemispatial neglect, anosognosia, apraxia and spatial disorganization. You would also expect to see numbness and weakness of face and upper limb on the contralateral side. ACA, also part of the anterior circulation, supplies the antero-medial surface. Occlusion will cause contralateral loss of sensation and motor function to the lower limb on the contra lateral side.

70 year old woman comes into the emergency room complaining of left side blindness that she first noticed when she woke up this morning. She has no headache, slurred speech, difficulty swallowing, weakness or gait disturbances. Patient has history of HTN, hyperlipidemia and a-fib. She is able to follow complex command and her speech is fluent. Physical examination reveals left homonymous hemianopia with macular sparing. There is decreased sensation over the left side of her body. Ther remainder of the nuerological examination is within normal limits. Non-contrast CT shows focal parenchyma hypoattenuation. Which of the following arteries is most likely compromised in this patient? PCA MCA ACA Ant. Choroidal Art. Artery of Pecheron Basilar artery

Sudden jerking of the arm at the should can cause a lesion to the lower trunk of the brachial plexus. The lower trunk carries nerve fibers from C8 and T1, which ultimately becomes the ulnar and median nerves. Together these two are responsible for all of the intrinsic muscle of the hand (e.g. lumbricals, interossei, thenar and hypothenar). Thus a tear in the lower trunk of the brachial plexus will lead to paralysis of all intrinsic muscles of the hand aka Klumpke's palsy. Weaknesses in the lumbricals will cause poor flexion of the hand at the metacarphalangeal joints and extension of the fingers at the interphalangeal joints causing the characteristic "claw hand" appearance. -Sensory loss to the medial hand and forearm. -T1 involvement can lead to Horner's syndrome. Axillary nerve lesion is associated with a break at the neck of the humerus. It innervates the deltoid muscle responsible for arm abduction. Long thoracic nerve injury is most commonly seen in axillary lymph dissection. This results in a wing scapula d/t lack of innervation to the serratus anterior muscle. Also patients cannot lift both of their arms up above their shoulders. The muscolocutaneous nerve is responsible for innervating the bicep brachii and brachialis. Thus lesion will lead to weakness in flexion of the forearm at the elbow. Radial nerve lesion is commonly associated with a break of the humerus at the midshaft. Patients may experience numbness to the posterior lateral part of the forearm and hand and paralysis of the extensor muscle of the wrist and fingers leading to the characteristic wrist drop appearance. The suprascapular nerve innervates the supraspinatus and infraspinatus. Nerve injury may result in inability to abduction and lateral rotation of the arm.

A 12 year old presents to the emergency accompanied by his mother complaining of right hand clumsiness. This happened a few hours ago when the boy fell from a tree and grabbed a branch with his right arm. He broke the fall with his feet safely with no head injury or loss of consciousness. On physical examination, the boy cannot perform fine finger movements with his right hand. What is the lesion? Axillary nerve Long thoracic nerve Lower trunk of the brachial plexus Musculocutaneous nerve Radial nerve Suprascapular nerve

This is polycytic astrocytoma, which is one of the two childhood tumor commonly found in the cerebellum (the other is medulloblastoma). It is cystic and well circumscribed that has a relatively benign course with good prognosis. Gross morphology is cystic and solid. Biopsy would reveal atypical astrocytes containing granular eosinophilic bodies and hair-like glial fibers known as Rosenthal fibers. Not medulloblastoma, which has Homer-Wright rosettes (small blue cells surrounding central area of neurofibrillary fibers), but it is in the cerebellum though. Not glioblastoma multiforme, which is more common in adults and is usually found in the cerebral hemisphere. Biopsy would have pseudopalisading pleomorphic tumor cells surrounding central areas of necrosis and hemorrhage. Not ependymoma, which also occur in children but usually arises at the 4th ventricle causing obstructive hydrocephalus. Histology would instead shows perivascular rosettes that has perinuclear rod-shaped blepharoplasts (basal ciliary bodies) that can be visualized in EM.

A 14 year old boy presents to the clinic with complaints of generalized headache, nausea, vomiting, ataxia and visual complaints. The headaches have been waking him up from sleep nightly. MRI shows a cystic tumor in the cerebellum. Biopsy shows atypical spindle cells with intracytoplasmic hair-like glial fibers and are associated with cysts. These are Rosenthal fibers and granular eosinophilic bodies. What is the diagnosis? Medulloblastoma Polycytic astrocytoma Glioblastoma multiforme Ependymoma Neruoblastoma

Vitamin E is a lipid soluble, anti-oxidant vitamin. It is widely found in almost everything we eat thus deficiency, however it can present in patients with malabsorption disorders and abetalipoproteinemia. The most notable presentations are hemolysis and neurological dysfunction (from free radical damaging cell membrane). -Neurological symptoms closely mimic that of Friederich Ataxia (AR degenerative condition) and Vitamin B12 deficiency (except for megaloblastic anemia, hypersegmented neutrophils or increase serum methylmalonic acid) because they affect the same parts of the nervous system. Patients from both disorders will have: a. ataxia (spinocerebllar tract) b. loss of proprioception and vibration (dorsal column) c. absent deep tendon reflex (peripheral neuron degeneration) -This is not acute intermittent porphyria because unlike Friredreich Ataxia, it is not associated with progressive spinal cord degeneration. Although patients will have peripheral neuropathy, AIP is also associated with abdominal pain. -Lead intoxication is characterized by irritability, loss of developmental milestone in infants and learning disability in adults. GI symptoms are also common presentation. -Poliomyelitis causes damage to the anterior horn causing asymmetric flaccid paralysis and hyporeflexia, but unlike Friedreich ataxia, the dorsal column is spared leaving intact sensation. -Creutzfeldt-Jakob encephalopathy will present with rapidly progressive dementia and myoclonic jerk of the extremities. -Thiamine (vitamin B1) def is associated with cerebellar damage but sensation is intact and the lateral spinal tracts (no hyporeflexia and flaccid paralysis)

A 16 year old boy is being evaluated for progressive gait instability, dysmetria and dysarthria. The patient no longer plays basketball for his school's team because of his symptoms. He has a brother that died of some neurological disorder. Physical examination reveals bilateral motor weakness of the lower extremities with no deep tendon reflex. In addition, he has a lost of sensation, vibration and proprioception. MRI of the spinal cord shows degeneration of the posterior cerebellum and spinocerebellar tract. Which of the following conditions closely resemble this patient's disease? acute intermitten porphyria lead intoxication poliomyelitis prion disease thiamine def vitamin E def

Fragile X is an X-linked inherited disease mostly affecting males, with minor deficits in female d/t XX chromosomes. It is the second most common cause of genetic intellectual disability (after Down syndrome). -It is a triplet repeat of (CGG)n (>200 repeats) -The defect will cause hypermethylation inactivating the FMR1 gene. Clinical findings include: -Long/narrow face. -Low set ears -Pronounced jaw -Large testes -Hyperlaxity of joints -Neurological features of intellectual retarded, delay in motor and speech development and neuropsychiatric disorders (e.g. ADHD, anxiety disorder and autism). -Complications include: Mitral valve prolapse Down syndrome is the most common congenital causes of intellectual disability. Mosaicism is when some but not all cells have the extra 21 chromosome, thus patients will have a milder phenotypical presentation. Klinefelter is (XXY) is associated with mild intellectual disability, gynecomastia, small/undescended testes, infertility, tall stature. Female pattern hair growth. Marfan is a AD disease affecting connective tissue. Patients often presents as: -Tall stature/slender -Increase arm to height ratio -Decreased upper and lower body segment ratio -Breast bone dips inward (aka protrudes outward) -Hyperlaxity of joints -Arachnodactyly -Ectopic lentis -However intellectual disability is not associated with Marfan. Prader Willi is an imprinting disorder caused by paternal deletion to part of the chromosome 15. In infancy, hypotonia and hyperphagia (abnormal increase of appetite) will cause motor delay and obesity, respectively. Patients can also present with autism and mental retardation. Ehlers Danlos is a connective tissue inherited disorder characterized by defective type IV collagen production. Patients often have hyper flexibility of skin, fragility and hyperlaxity. But not associated with intellectual impairment.

A 16 year old boy with mild intellectual disability presents to the clinic for his ADHD evaluation. Parents claim that he has always been inattentive and impulsive. His teacher is concerned about his poor grades. Medical record shows a history of gross motor and speech delay, for which he has therapy for during childhood. Physical examination shows long/narrow face, prominent mandible and large testes. What does he most likely have? down syndrome mosaicism ehlers danlos fragile x klinefelter marfan prader willi

This patient has myotonic dystrophy an AD inherited triplet repeat of (CTG) that codes for a myotonia protein kinase (DMPK gene). The repeat increases with successive generation, thus symptoms will present in earlier compared to previous generation (anticipation). On light microscopy, preferential type 1 fiber atrophy along with, but unlike Duchenne it doesn't have necrosis of muscle fibers and fibrofatty replacements. -Clinical presentations arise in early adulthood. Cataracts are seen in virtually all patients and other common features are frontal baldness, muscle wasting, testicular atrophy and arrhythmia. However, myotonia is the cardinal feature where patient cannot relax muscle.

A 17 year old patient comes into the office complaining of his inability to let things go with his hands sometimes, such as unable to release and handshake or the doorknob after opening. His dad has similar symptoms although less mild. He is bald, has gonadal atrophy and cataracts. Biopsy reveals mostly atrophic type 1 motor fibers. What does he have? -Etiology? -Pathogenesis? -Clinical presentation?

Campylobacter jejuni -Major cause of bloody diarrhea -Comma or S shaped, oxidase positive -Campylobacter likes the hot campfire (grows at 42) -Type 2 hypersensitivity

A 32 year old man presents to the emergency room complaining of bilateral leg weakness and tingling sensation of the feet. Physical examination reveals bilateral weakness of legs and absent of S1 tendon reflex. Patient's history was pretty much unremarkable except for diarrhea he suffered two weeks ago that had already resolved. What infection does he have?

Patients symptoms and clinical features are indicative of Dandy-Walker malformation characterized by lack of cerebellar vermis, enlargement of posterior fossa causing patients to have a progressively large head, and agenesis of the foramina of Mengidie and Luschka causing non-communicating hydrocephalus and increase intracranial pressure causing irritability, nausea and vomiting. Cerebellar dysfunction may cause gait disturbances and delayed development of motor skills. Other features include atrophy of corpus callosum and malformation involving face, limb or heart. -Arnold Chiari malformation aka Chiari II malformation characterized by displacement of the cerebellar vermis and tonsil through the foramen magnum causing non-communicating hydrocephalus. -Arteriovenous malformation is characterized by multiple intracranial hemorrhage and lesion leading to seizures, headaches or focal neurologic deficit. -Encephalocele is a rare neural tube defect where the brain and meninges protrude through an opening in the skull.

A 2 year old boy is brought to the doctor office by his mom complaining of the boy's constant irritability and excessive crying. The pregnancy was uneventful however the delivery was C-section d/t obstructed labor. His mother states that the boy motor skill such as lifting his head up, sitting and walking developed much slower than his brother. She also noticed that her son's head is much bigger than the kids his age. His weight is in the 60%tile, his high is 50% and his head circumference is at 95%. CT scan show enlarged posterior fossa and absence of a cerebellar vermis. What is his diagnosis? -Arnold-Chiari malformation -Dandy-Walker malformation -Arteriovenous malformation -Encephalocele -Hypoxic ischemic injury

This patient most likely have lesion to his musculocutaneous nerve, which is injury most commonly seen in shoulder dislocation and strenuous physical activity (e.g. pitching). This nerve arises from C5-C7 spinal nerve roots that turns into the lateral cord of the brachial plexus. It innervates the major muscle responsible for forearm flexion (biceps and brachialis) and the coracobrachialis (arm flexion and adduction). After innervating these muscles, it becomes the lateral cutaneous nerve giving somatosensory input from the lateral forearm. -Medial forearm sensation is supplied by the medial cutaneous nerve of the forearm a branch of the medial cord (bottom cord) of the brachial plexus. -Posterior arm and forearm receive innervation from the posterior cutaneous branch of the radial nerve. -Thenar eminence sensation is supplied by the medial nerve.

A 20 year old male comes in complaining of right arm weakness. He is a competitive baseball pitcher and have been pitching a lot since his team has made the playoffs. Since then, he has been having difficulty lifting things up. He has no known head, neck or axillary injury. On physical examination, patient has weakness flexing his forearm at the elbow. This patient would most likely have lost of sensation to which of the following areas? -Medial forearm -Lateral forearm -Posterior forearm -Thenar eminence -Posterior arm

The radial nerve initially starts out in the axilla, medial to the surgical neck of the humerus and inferior to the teres minor. It continues posteriorly passing between the long head of the tricep brachii and the posterior humerus, passing through the radial groove at the midshaft. This type of injury is mostly seen in patients with ill fitting crutches (aka crutch palsy), passing out with arm over a chair (aka Saturday night palsy) or a midshaft break (tricep reflex will be present because innervation is given before coursing towards the posterior midshaft). -The radial nerve innervates the muscles responsible for forearm, hand and finger extension. Thus patients will presents with wrist drop and absent tricep reflex. Sensory lost will be over the posterior arm, posterior forearm, posterior 2/3 of the hand and just the thumb. -The proximal median nerve is responsible for sensory over the 2/3 palmar aspect of the first three digits. It also also responsible for flexion/opposition of the thumb, flexion of the 2nd and 3rd digits, and wrist flexion and abduction. -Axillary nerve innervates the teres minor and deltoid responsible for arm abduction. Sensory over the deltoid area. Usually occur with a surgical neck fracture. -Accessory nerve comes out of the jugular foramen. It courses over the levator scapulae to innervate the trapezius and sternocleidomastoid. -Long thoracic innervates the serratus anterior causing wing scapula. Patient tend to have trouble abducting their arm over 90 degrees. -Suprascapular nerve innervates the suprascapula that function to abduct and laterally rotate arm.

A 25 year old male comes into the office complaining of right arm weakness. He was involved in car accident last week and broke his fibula. He is in a cast and on crutches. He denies recent trauma, neck pain or head pain. Upon physical examination, he has upper right extremity weakness of wrist extension and there were no tricep reflex. What nerve is messed up? -median -axillary -radial -accessory -long thoracic -suprascapular

Patient has ascending paralysis after an infection of some kind is characteristic of Guillain-Barre, which is strongly associated with C. jejuni but can occur after an upper respiratory, immunization or allergic reactions. -Pathogenesis is antibody cross linking with myelin of nerve roots and peripheral nerves. On light microscopy, segmental demyelination can be seen accompany by "endoneural inflammatory infiltrate" consisting of lymphocytes and macrophages.. -This demyelination causes flaccid paralysis and areflexia. Paralysis of respiratory muscle, CN VII (Bell's palsy) and other CNs can be seen. -CSF will have elevated protein with only normal to slightly elevated cell count. -Toxin penetrating the nerve blood barrier is associated with diphtheria. -Endoneural arterial hyalinization is a complication of diabetes aka diabetic microangiopathy. It leads to narrowing of blood vessels causing ischemic nerve injury. This one part of the pathogenesis. Another contributing factor is the accumulation of fructose and sorbitol. -Duchennes and Becker's are mutations to the dystrophin gene. Duchenne's is complete absent while Becker's is mild and less severe. -Endomysial inflammatory infiltrate of the skeletal muscle is a characteristic of polyomyositis. Characterized by bilateral weakness of proximal muscles however deep tendon reflex is preserved.

A 25 year old man presents to the clinic with bilateral leg weakness, which started a week ago and is progressively getting worse. Physical examination shows weakness and no reflexes. Has a history of upper respiratory infections a couple of weeks ago. What would you expect to see? -endoneural inflammatory infiltration -toxin penetrating the nerve blood barrier -endoneural arterial hyalinization -mutations of structural protein in muscle -endomysial inflammatory infiltrate

This patients symptoms of bilateral loss of pain and temperature sensation is caused by syringomyelia, a cyst filled with CSF fluid usually appears at the cervical region. The first clinical manifestation is d/t impingement of the anterior white commissure, where patients would have complete anesthesia that usually starts two levels below the lesion and two levels after the lesion. Cyst can enlarge and impinge on the ventral horn causing flaccid paralysis, areflexia, fasciculations and atrophy of the intrinsic muscles of the hand. In some cases it can impinge the intermediolateral column leading to Horner's syndrome. -This is not a dorsal column lesion which would cause lost of light touch, vibration and proprioception at the level of the lesion ipsilaterally, because unlike the lateral spinothalamic tract, it decussate in the medulla instead of decussating right away. This is mostly seen with tabes dorsalis that preferentially cause damage to the dorsal root and dorsal column. Patients would have lost of proprioception, light touch and vibration, thus standardized patient would have ataxia and unbalanced gait. -This is not a dorsal horn lesion because patient would have contralateral lost of pain and temperature (2 or 3 levels below the lesion) and ipsilateral lost of vibration, proprioception and light touch at the level of the lesion. -This is not the ventral horn lesion which is seen classically in polyomyelitis, which preferentially damage this region. A lesion here would cause a lower motor neuron lesion characterized by flaccid paralysis, fasciculations, muscle wasting and areflexia. However their sensations are intact. -The lateral spinothalamic tract belonging to the ascending second order neuron responsible for sensation of pain and temperature. Preferential lesion to this area would lead to lost of pain and temperature on the contralateral side, unlike syringomyelia which causes bilateral lost of sensation to pain and temperature. -Ventral spinothalamic tract (not to be confused with lateral spinothalamic tract) plays a minor role in light touch, proprioception and vibration.

A 25 year old woman presents to the clinic complaining multiple burns to both of her hands. This happens most often when she is cooking as she is taking things in and out of the oven, and also in the morning to test the hotness of water before taking a shower. She doesn't noticed the burns until she looks at her hand. She had her wisdom tooth removed last year. Had a mother who died of MS. Doesn't drink, smoke or do illicit drugs. Examination reviews diminished pinprick across the upper back, shoulders and arms. Light touch, vibration and proprioception are intact. Examination of lower extremities is unremarkable. Lesion to which of the following places is highly suggestive in this patient? -Dosral horn -Ventral horn -Lateral spinothalamic tract -Anterior white commissure -Dorsal column -Ventral spinothalamic tract

This patient's symptoms are suggestive of a V3 (trigeminal mandibular branch) lesion. It is responsible for innervation of the muscles of mastication as well as sensation to that area of the face. The muscle of mastications are the massater, lateral pterygoid, medial pterygoid and temporalis. Only the lateral pterygoid is responsible for opening of the mouth, and the other three are responsible for closing. Unilateral CN V3 lesion will cause jaw protrusion towards the side of the lesion from unopposed pterygoid muscles on the other side. Bilateral lesion will cause jaw drop with lack of movement. It exits the skull through the foramen ovale along with the lesser petrosal nerve, accessory meningeal artery and emissary veins. The second division of the CN V2 is the axillary nerve. It exits the skull via the foramen rotundum, which contains the middle meningeal artery/veins and recurrent meningeal branches of V3 providing sensation to the dura and has sympathetic activity. The first division of trigeminal (V3) is the opthalmic branch that leaves the brain via the superior orbital fissure. The jugular foramen contains CN IX, X and XI, the petrosal and sigmoid sinuses and posterior meningeal artery.

A 26 year old healthy man presents to the emergency room d/t motorcycle accident. He was found to have maxillofacial injury. His conditioned is stabilized and surgery was performed. While recovering, the patient develop difficulty chewing food. On examination, his jaw protrude to the right side when he was instructed to open his mouth. This nerve responsible for his symptoms leave the brain through what foramina? Foramen lacerum Foramen rotundum Foramen ovale Forman spinosum Jugular foramen

The combination of nicotinic (diplopia and dysphagia) and muscarinic (dry mouth) inhibition are strongly suggestive of Botox poisoning. -People usually get this by eating ill-prepared home made canned food with preformed neurotoxin made by C. botulinum. The toxin inhibits the release of acetylcholine therefore it affects both nicotinic and muscarinic actions. This effect can be partially overcome by high rate repetitive nerve stimulation, which explain the impaired CMAP in this patient. -The classic presentations are the 3 D's (diplopia, dysphagia and dysphonia) can developed within 12-36 hours. -There are two other forms of botulism. One is found in wound and the other is found in honey causing infant botulism, where baby consume spores, the bacteria grows and produce toxin. All of which are medical emergencies!!!! -Diarrhea after eating chicken in the past is suggestive of Gullain-Barre. -History o episodic ptosis and diplopia usually worsens throughout the day is myasthenia gravis. -Tetrodotoxin inhibits Na influx into cell causing paralysis, paresthesia, loss of reflexes and sometimes severe hypotension. Patients are conscious by complete paralyzed. -Tricyclic antidepressant overdose do present as anti-cholinergic symptoms, but this is just muscarinic, not nicotinic, so you won't have CMAP effect.

A 34 year old patient comes into the emergency room with complaints of dysphagia, dry mouth, diplopia and blurry vision. History of major depression. PE shows mydriasis and poorly reactive pupils. Electrodiagnostic studies reveal normal nerve conduction but decreased compound muscle action potential (CMAP). Which of the following things should be ask with this patient? -Have you eaten any home canned foods lately? -Have you recently had a diarrhea after eating chicken? -History of episodic ptosis and diplopia? -Recent exposure to puffer fish? -Tricyclic antidepressant overdose

Synaptophysin is a transmembrane glycoprotein found in the presynaptic vesicles of neurons, neuroectodermal and neuroendocrine cells. Immunoreactive to synaptophysin indicates that this tumor arise from neuronal origin. Such tumors are rare compare to gliomas (glial cell origin) being most common followed by meningioma and pituitary adenoma. However, the majority of brain cancer are not primary with the majority arise d/t metastasis. Children tumors tend to be subtentorial while adult tumors are supratentorial. -Glial cells (astrocytes, oligodendrocytes and ependymal) all stain positively for GFAP. The arachnoid villi meningioepithelial cells are neither of this so they would not stain positively for any of these things.

A 36 year old woman comes to the clinic complaining of tonic-clonic seizure. CT of brain reveal an intracranial mass. Biopsy is positive for synaptophysin and negative for glial fibrillary acidic protein. Which of the following cells is likely the origin of this tumor? Astrocytes Ependymal Oligodendreocytes Meningioepithelial cells Neurons

This patient symptoms and history is highly suggestive of early onset Alzheimer dementia. Characteristic of this is intracellular neurofibrillary tangles and extracellular amyloid-beta plaques. Neurofibrillary tangles are made out of hyperphosphorylated Tau protein (basic component of microtubule) that causes the microtubule structure to collapse into "tangle" contributing to global neuronal dysfunction. Amyloid beta plaques are abnormal fragments of amyloid precursor protein which is normally involved in synaptic repair and formation. In Azheimer dementia, this protein is not properly cleared and hardens depositing in blood vessels and brain tissue. The APP gene is on Chromosome 21. The extra chromosome 21 in Down Syndrome patients is thought to contribute to high amount of APP. Mutation of the TTR gene can lead to misfolding of transthyretin (aka pre albumin). This causes familial amyloid polyneuropathy or familial amyloid cardiomyopathy. Huntington's is associated with CAG triplet repeat. Patients tend to have chorea, psychiatric changes and dementia. Presynaptic acetylcholine levels are decreased in Alzheimers d/t down regulation of choline acetyl transferase. Consequently, patients will have to take an anti-acetylcholineesterase inhibitor. Mutation of the gene coding apo E4 results in impaired synthesis of this protein and clearance of Amyloid-beta plaques eventually leading to Alzheimers, but this mutation is associated with higher onset Azlheimers.

A 41 year old patient with Down Syndrome presents to the clinic with cognitive decline. The patient has a history of moderate intellectual disability, but his higher cognitive function has been progressively declining in the past couple of years. He previously volunteered at the local library but lost his position because he can no longer perform his duties. The patient is now completely dependent on a caregiver for basic needs such as bathing, getting dressed and using the toilet. The caregiver has noted the patient tends to wonder and often time get lost. Which of the following is mostly increased in this patient? Extracellular transthyretin Gene specific CAG triplet repeat Presynaptic acetylcholine Neuronal amyloid precursor protein Serum apo E4

CSF circulating the ventricles are constant being secreted by the choroid plexus and absorption by the arachnoid vili. Hydrocephalus is enlarged ventricles (can be either normal or high pressure) cause by: a) Loss of central neuronal volume (hydrocephalus ex-vacuo) b) Excessive CSF accumulation Patients with neurodegenerative diseases (e.g. AIDS dementia, Alzheimer) can develop hydrocephalus ex-vacuo d/t severe cortical atrophy, which allows patients ventricle to expand while maintaining normal pressure. Ventricular enlargement caused by excessive CSF accumulation can be either: 1) Obstruction (noncommunicating hydrocephalus) of circulation 2) Defective absorption (Noncommunicating hydrocephalus) at the arachnoid vili. There are two types of noncommunicating hydrocephalus. i) normal pressure hydrocephalus - chronic defective absorption of CSF at arachnoid vili resulting in enlargement of ventricles. Because the condition is chronic, the ventricles enlarge slowly causing normal pressure. Patients will present with ataxia, followed by frontal lobe atrophy and urinary incontinence ii) high pressure hydrocephalus more acute impairment of CSF absorption seen in cerebral venous sinus thrombosis, subarachnoid hemorrhage and meningitis. Lissencephaly (AKA agyri) is a congenital abnormality characterized by lost of gyri. Patients will have severe mental retardation and seizures. On gross imaging and brain radiography, the brain surface has a smooth appearance. Pseudotumor cerebri is also known as idiopathic intracranial hypertension characterized by elevated CSF pressure without ventricular enlargement. Patients are usually female, obese and presents with headache and papilledema, with vision loss as complication from optic neuropathy. Uncal herniation can be cause by intracranial mass (tumor, hemorrhage) or cerebral edema. This may lead to occlusion of the ipsilateral occulomotor as well as the PCA. A fixed dilated pupil on the same side of the lesion is the first sign of uncal herniation.

A 43 year old man with HIV who is noncompliant with anti-retroviral treatments presents to the office complaining of progressive memory loss and cognitive decline over the last several years. The patient has problem with attention, concentration and speech. The fast few month he has been increasingly lethargic and apathetic. More recently, he has been having problem with balance and has fallen multiple times. The patient doesn't have fever, headache, tremor, vision problems or urinary incontinence. Mini-mental test shows a score of 18/30 and the patient appears to be emotionally blunted. He has postural instability and problem performing fine motor task. Noncontrast CT shows diffuse cortical ventricle enlargement. This patient's condition can be describe as what of the following? -communicating hydrocephalus -noncommunicating hydrocephalus -hydrocephalus ex-vacuo -Lissencephaly -Pseudotumor cerebri -transtentorial (uncal) herniation

The most common CNS tumor in immunosupressed patients are CNS Lymphoma commonly associated with AIDS. They appear as uniformly dense atypical lymphoid cells (majority is B-cell origin), with diffuse large cell lymphoma being the most common subtype. Usually have positive CD20 and CD79a marker. Tumor is most commonly associated with EBV virus with general non-specific symptoms of seizures, mental status change or progressive focal deficit. They respond very poorly to chemo. -This is not polycystic astrocytoma because polycystic (low grade) astrocytoma usually arise in the cerebellum and has Rosenthal fibers. -Glioblastoma is a highly malignant astrocyte tumors that has pseudoplasiading pleomorphic tumor cells bordering areas of necrosis and hemorrhage. -Oligodendroglioma has fried egg appearing cells that usually arise in the frontal lobe. -Ependyomoma are childhood tumor usually found at the fourth ventrical with cells forming perivascular rosettes. -Meningioma is usually found attached to dura matter. Histology will show psammoma bodies. -Craniopharyngioma are childhood tumor at the pituitary. Histology shows calcification that are tooth enamel like. -Schwannoma are found outside the CNS with acoustic neuropathy.

A 43 year old man with advanced HIV comes to clinic complaining of recent onset of headaches and personality changes. Imaging of the brain shows a solitary mass in the temporal lobe. Biopsy mass shows uniform cells containing EBV genome. Which of the following does this patient have? Polycystic astrocytoma Glioblastoma Oligodendroglioma Ependymoma Medulloblastoma Primary CNS lymphoma Meningioma Craniopharyngioma Schwannoma Pituitary adenoma

Pure motor hemiparesis and the small cavitary lesion are highly suggestive of a lacunar infarct. This is ischemia to the deep penetrating branches that supply the deep brain structures (basal ganglia and pons) and subcortical white matter (internal capsule, corona radiate). The primary cause of this is chronic hypertension in addition to smoking and DM. The arterioles undergo lipohyalinosis, microatheroma formation and occlusion (aka hypertensive arteriolar sclerosis). Depending on the area that is affected patient can present with: 1) pure motor hemiparesis - posterior limb of the internal capsule or basal pons 2) pure sensory - VPL and VPM of the thalamus 3) Ataxia-hemiplegia - posterior limb of the internal capsule or basal pons 4) Dysarthria/clumsy hand syndrome - genu of the internal capsule or basal pons. Investigations: in acute scenarios, CT scan are often unremarkable, however several weeks later, as these necrotic lesions turn into cavitary spaces, you will see hypodensity lakelike scar tissue called lacunae. -This is not arteriovenous malformation which can cause stroke but this is a congenital abnormality thus you expect to see it in children. -Cardiac embolism would most likely cause infarction of larger veins such as MCA or ACA affecting a larger area thus patients will present with more symptoms. -Cerebral amyloid angiopathy is the most common spontaneous lobar/cortical hemorrhage (e.g. occipital parietal) in elderly patients. -Charcot-Bouchard rupture can cause similar symptoms, however interparenchymal hyperdensity is seen on initial CT. -Hypertensive encephalopathy is characterized by progressive headaches, then nausea vomiting and then non localizing CNS lesion such as confusion. -Giant cell arteritis (aka temporal arteritis) affect medium to large size arteries. Patients often have subacute onset of headache, jaw claudication, monoocular vision lost and polymyalgia rheumatica. -Saccular aneurysm is associated subarachnoid hemorrhage (communicating arteries). Abrupt severe headache. CT scan shows hyperattenuation.

A 45 year old man presents to the emergency with complaints of sudden right sided weakness. His sensation is intact, he denies vision problems, dysphagia, aphasia or balance problems. He has history of poorly control hypertension. His mother has coronary heart disease and his father died of a stroke. CT was unremarkable. Four weeks later he returns for another CT scan of the brain and imaging shows 9mm lakelike cavitary lesion located at the left internal capsule. This patient's condition is most likely caused by which of the following? -arteriovenous malformation -cardiac embolism -carotid artery atherosclerosis -cerebral amyloid angiopathy -Charcot-Bouchard aneurysm -hypertensive arteriolar sclerosis -hypertensive encephalopathy -large vessel arteritis -saccular aneurysm

Diabetic neuropathy is the most common complication of DM 1 and 2. There are 2 mechanisms: 1) non-enzymatic glycosylation of proteins that lead to increased thickness, hyalinization and narrowing of luminal wall causing ischemia of the endoneural arterioles. 2) high glucose level will lead to conversion of it into sorbitol and fructose by aldose reductase. Sorbitol is osmotically active cause influx of water into the cell causing osmotoic damage of axons and myelin. The most common diabetic neuropathies are: 1) Distal symmetric polyneuropathy affecting motor (LMN lesion: weakness, decrease DRT & atrophy), sensory (decrease sensation of all things, intense burning, tingling and numbness). Glove stocking distribution involving hands and feet. 2) Autonomic: GI (gastroparesis, constipation), CVS (orthrostatic hypotension), Urinary (overflow incontience, neurogenic bladder) and sexual (erectile dysfunction & ejaculatory abnormalities) 3) Mononeuropathy: cranial nerves (CN III, CN VII and CN II, from ischemic optic neuropathy. Somatic mononeuropathies (common bilateral involvement of median, ulnar and peroneal nerves). -Endoneural inflammatory infiltrate is associated with Guillain-Barre syndrome. -Mutation of myelin protein is associated with Charcot-Marie-Tooth syndrome. -poor signal transduction at NMJ is associated with myasthenia gravis (post synaptic ACh receptor) and Lambert Eaton (presynaptic Ca channel, associated with small cell lung carcinoma

A 45 year old obese woman with history of type II diabetes, HTN and gout complains of tingling and burning sensation in both of her feet that have been progressively worse over the past 3 months. She noticed a painless ulcer on her right foot about 2 weeks ago that has been getting progressively bigger. What is most likely associated with her symptoms? -hyalination of endonerual arterioles -endoneural inflammatory infiltrate -mutation of myelin protein -Nerve compression -poor signal transduction at NMJ

Positive VDRL in CSF indicates neurosyphilis, which preferentially degenerate the dorsal root causing secondary demyelination of the dorsal column. Patient would have lancinating pain, paraesthesia and loss of vibration and proprioception. Loss of proprioception is compensated by visual cue, however this predominates in the dark, therefore patients will have a positive Romberg test. Arefelexia and loss of bladder function may also occur.

A 45 year old patient comes into the office complaining of brief severe pain to his extremities. He frequently stumble and fall at night. CSF positive for VDRL. Which of the following areas of the spinal cord is affected? -Dorsal horn -Ventral horn -Lateral spinal thalamic -Anterior white commisssure -Dorsal column

Patient history and positive right straight leg test are highly suggestive of sciatica from a herniated disk compressing the lumbosacral nerve roots. Irritation of nerve roots will result in dermitomal and myotomal deficit (radiculopathy) corresponding to the nerve root level. Patient may have worsening radiculopathy pain when the hip is passively flex with extended knee (straight leg test). The sciatica nerve root is derived from L4-S3 where compression most commonly occur at the L5. These patients will exhibit pain and paraesthesia radiating down the buttock (lateral), lateral thigh, anterio-lateral leg and dorsal foot. Patients may also have weakness in dorsiflexion (tibialis anterior), foot eversion (peroneus) and toe extension (extensor digitorum brevis) However, this patient has a S1 compression with the characteristic pain/paraesthesia radiating down the medial buttocks, posterior thigh and leg, and lateral foot. Weakness in hip extension (gluteus maximus), knee flexion (hamstring) and plantar flexion (gastrocnemeus). Absent ankle reflex. Patients with L2 and L3 compression will have pain and numbness radiating down the anterior part of their thigh with weaknesses in hip flexion (iliopsoas). Knee and ankle reflex would be intact. Patients with L4 radiculopathy will have pain and numbness radiating down the anterior part of the thigh to the medial leg and foot.

A 45 year old woman presents to the office with complaints of severe back pain. She said it started with she was lifting a heavy box. The pain starts in right lower back and radiates down the posterior thigh and calf and lateral foot. Upon physical examination, straight leg test was positive on the right. She has weakness on right hip extension compared to left. Knee jerk reflex is +2 bilaterally. Right ankle reflex is absent. Which of the following nerve root is mostly impinge in this patient? L2 L3 L4 L5 S1

Gait ataxia and instability are signs of cerebellar lesion. The two most common childhood primary brain tumors affecting the cerebellum are polycystic astrocytoma and medulloblastoma. Biopsy is needed to differentiate pathology. -Medulloblastoma is a highly malignant cerebellar tumor. It is a form of primitive neuroectodermal tumor characterized by sheet of primitive cells with many mitotic figures. Cells have deeply basophilic nuclei with scant cytoplasm with mitotic figures and Homer-Wring rosettes. It is aggressive can have drop metastases to spinal cord. Along with its cerebellar dysfunction, it can also compress the 4th ventricle leading to noncommunicating hydrocephalus (lethargy, morning headache, vomiting). -Polycystic astrocytoma is the most common childhood primary brain tumor that usually occur at the cerebellum. With similar clinical presentation, biopsy is needed to differentiate it from medulloblastoma. Microscopically polycystic astrocytoma have cystic astrocytes with Rosenthal fibers (eosinophilic corkscrew fibers). It is GFAP positive and has a good prognosis. -Ependynoma is an ependymal cell tumor most often presents at the 4th ventricle causing hydrocephalus. It has characteristic perviascular rosettes. Rod shaped blepharoplasts (basal ciliary bodies) found near the nucleus. Assoicated with a poor prognosis -Craniopharyngioma is a benign childhood tumor derived from the Rathke's pouch. It is most commonly confused with pituitary tumor since causes bitemporal heminopia d/t compression of the optic chiasm. it is the most common supratentorial tumor. Microscopic characteristics are calcification and tooth enamel like.

A 5 year old boy presents to the clinic with gait ataxia and instability. MRI shows a mass located at the midline posterior fossa. Biopsy reveals sheets of primitive cell with many mitotic figure. What does this patient most likely have? Polycystic astrocytoma Ependymoma Medulloblastoma Craniopharyngioma

There are three major types of glial cells that are non-excitable and serve to support and protect the CNS. 1. Astrocytes - small round vesicular nuclei containing glial fibrils that stains GFAP. These guys do a lot of shit, such as support, repair, BBB and metabolic. 2. Oligodendrocytes - have small round nuceli surrounded by perinuclear halo that posses few processes than astrocytes. Their main job is to produce myelin. 3. Microglia - this is the only glial cell that are not of neuroectoderm origin. They are monocytes in the bone marrow that travels to the brain and differentiate into macrophages, called microglia. They have small elongated nuclei with many short branching processes. Their main role is to phagocytose shit. This question stem is suggesting this patient is having an ischemic infarct causing coagulative necrosis. If irreversible neuronal death occurs, Gliosis would occur resulting in glial hyperplasia. One of the main functions of astrocytes is to repair. In an event of irreversible damage, astrocytes would proliferate at the site of lesion. This is an universal response of CNS damage known as astrocytosis. These astrocytes have round nuclei with a large number of fibrils and glycogen containing granules. Proliferated astrocytes replacing lost neuron to compensate for their volume in order to maintain intracranial pressure. Later, after neuronal death, astrocytes processes would link up forming gliotic scar scar. -Neuronal hypertrophy does not occur in irreversible damage. They shrink and are extremely eosinophilic that will get phagocytized by microglia. -Fibroblast migration to site of injury only occur outside of the CNS, not inside. -Neither vascular hyalinization and extracellular amyloid deposit occur in normal tissue repair, both of these are pathological.

A 54 year old man shows neuronal shrinkage and intense cytoplasmic eosinophilia. If her survives, what would would occur in this area? neuronal hypertrophy fibroblast migration vascular hyalinization extracellular amyloid deposition glial hyperplasia

This guy has myasthenia gravis. An autoimmune condition where auto-antibodies attack the Ach receptors causing impaired propagation of action potential in the post synaptic membrane of NMJ. Patients have muscle weakness especially of the eye extraocular muscles causing ptosis (especially when patient looks upward) and diplopia that worsens as the day progresses. Electrophysiology will show decreasing force of muscle contraction. Most patients develops thymic abnormalities (e.g. thynoma and thymic hyperplasia). -Antibodies against presynaptic calcium channel is characteristic of Lambert-Eaton where patients often present with proximal weakness in the extremities. This is classical complication of small cell carcinoma. -Segmental demyelinzation of peripheral nerve tissue with infiltration of lymphocytes and macrophages are characteristic of Guillain-Barre classically presents after Campylobacter jejuni infection. Patients presents with acute polyneuropathy usually present with ascending paralysis. -Poliomyositis is CD8 mediated skeletal muscle damage and usually presents with proximal muscle weakness. -Vascular deposition of circulating immune complexes are characteristics of SLE, RA and other connective tissue disorders.

A 55 year old patient complains of visual problems for the past few months. He says his eyes' tired easily especially late afternoon or night. Patient smokes a pack of cigs a day for the past 10 years. He doesn't drink or do illicit drugs. PE shows weakness of extraocular muscles. Pupillary reflex, deep tendon reflex and sensation are all intact. CT scan shows an enlarged thymus mass. What is the most likely mechanism for this person's symptoms? -Antibodies against a neurotransmitter receptor -Antibodies against presynaptic calcium channel -CD8 mediated nerve fiber demyelinization -CD8 mediated skeletal muscle damage -Vascular deposition of circulating immune complexes.

This patient exhibits a "clasp-knife" spasticity, which is characterized by resistance to passive arm extension followed by a sudden release of the tension. This type of spasticity is characterized by an upper motor neuron lesion, a lack of upper motor neuron inhibition on the reflex arc. Upper motor neuron lesion can happen any where in the pyramidal tract including the cortical spinal tract of the spinal cord, the brain stem, internal capsule and the precentral gyrus (primary motor cortex). Patients with internal capsule stroke usually suffers from pure motor impairment to the contralateral leg, arm and lower face. Contralateral spasticity, increased tone, hyperreflexia and positive Babinski sign can be present. -Internal capsule lesion is most commonly cause by a intraparenchymal lacunar infarct (e.g. penetrating artery supplying blood supply to deeper brain tissue, such as the lenticulostriate artery or *Charcot-Bouchard* aneurysm) secondary to hypertension. -Keep in mind that the lenticulostriate arteries are the first branches of the middle cerebral artery. Caudate nucleus (basal ganglia) lesion would present with extrapyramidal signs of athetosis and chorea. Atrophy of caudate nucleus is a common presentaiton of Huntington. The putamen is part of the basal ganglia (extrapyramidal motor system). It is responsible for initiating movements. Lesion can cause contralateral tremor, rigidity and bradykinesia. Globus pallidus is also part of the basal ganglia, the extrapyramidal motor system. It is charge of regulating movements. Splitting up into the GPi and GPe, lesion to the latter will cause decreased movement while impairment of the former will cause increase movement. The insular cortex (insula) is responsible for integrating body state with emotions (limbic), ANS control and conscious monitor of visceral sensation.

A 62 year old male comes to the emergency room with complaints of left arm clumsiness. PE shows weakness in left arm and leg. His speech is slurred and there was drooping of his left lower face. On passive extension of the arm, there is an initial resistance followed by sudden release of tension as extension continues. A lesion affecting which of the following site does he most likely have? Caudate nucleus Internal capsule Putamen Globus pallidus Insular cortex

This patients history of smoking and presentation of upper right arm pain and weakness accompanied by partial ptosis and miosis of right eye is suggestive of a Pancoast tumor, a space occupying lesion that compresses the brachial plexus and cervical sympathetic ganglion, causing pain and weakness along with ptosis (superior tarsal), miosis (unopposed CN III) and anhydrosis d/t no sympathetic innervation of facial sweat glands (Horner's syndrome), ipsilaterally to the lesion. Pathway: -First order neurons originate from the hypothalamus and descend through brainstem to the spinal cord's (C8-T2 segments) intermediolateral segments where they synapse with second order neurons. -These second order neurons exit the spinal cord through the ventral nerve root and the anterior white commissure to the superior cervical ganlion where they synapse with third order neurons that have postganglionic fibers that travel with arteries to get to their destination. Both brainstem and spinal cord lesions can cause Horner's syndrome, but it usually associated with the contralateral signs of hemiparesis and pain. In addition, brainstem lesion will most likely have accompanying deficits of CNs causing diplopia, vertigo and ataxia. Spinal lesion can cause ipsilateral symptoms but only below the lesion. Damage to the cerberal cortex and basal ganglia (subcortical gray matter) is not associated with Horners. Vagus nerve lesion does not cause Horner's syndrome but you will have ipsilateral paralysis of soft palate, pharynx, and larynx producing dysarthria, dysphagia, hoarseness and loss of gag reflex (efferent limb). On examination, uvula will deviate away from the side of the lesion d/t weakness of the levator veli palatini. -Pancoast tumor is a non-small cell tumor (e.g. squamous and adeno) that arises at the superior sulcus. Patients will have ipsilateral arm pain and weakness, along with Horner's syndrome from lesion to the sympathetic ganglion.

A 64 year old smoker comes in and complains of right shoulder pain radiating to the ipsilateral arm. He has weakness in right upper extremities. On neurological examination, patient is oriented, conscious, alert and follows commands. He has partial right sided ptosis with intact ocular movements. HIs pupils are asymmetric with right side being smaller. The pupils become more symmetric in bright light. Right upper extremities have 3/5 in strength and absent of deep tendon reflex. This patient's autonomic dysfunction is associated with which of the following things? autonomic ganglia brainstem cerebral cortex spinal cord subcortical gray matter vagus nerve

This patient's symptoms and clinical presentations are highly suggestive of normal pressure hydrocephalus which is characterized by progressively worsening symptoms d/t compression of the white matter. The cause of this communicating hydrocephalus is due to decreased absorption of CSF by the arachnoid villi, mostly likely from trauma or subarachnoid causing scarring of the villi. The symptoms are progressive because of the slowly growing ventricles expanding to maintain normal pressure. Gait disturbance appears first where patient would have a slow, short gait characterized by low rising feet (aka magnetic gait). Upper motor neuron lesion symptoms can be seen (e.g. spasticity, hyperreflexia). As it advances, patient will start to have problem with motor planning, execution and overall cognitive disturbances (e.g. difficulty concentrating and lack of attention). Urinary incontinence can be seen in the later stages of the disease. It is commonly the urgency type d/t lack of frontal lobe inhibition of the bladder contraction. Ventriculomegaly out of proportion to or without sulci enlargement is a classic CT characteristic of NPH. Improvement of symptoms be reducing CSF is diagnostic. -Alzheimer's disease is characterized by forgetfulness first, not gait disturbance. Communicating hydrocephalus may occur but enlarged ventricles proportional to enlargement of the sulci d/t cerebral atrophy (e.g hydrocephalus ex-vacuo). -Parkinson early symptoms are resting tremors, rigidity and bradykinesia. Patients typically present with cognitive deficits, mood disturbances and postural instability as the disease progresses -Frontaltemporal dementia (Picks) is a common cause of dementia in younger patients characterized by neuronal degeneration of the frontal and temporal lobe. Early symptoms includes personality changes and aphasia. -Major depressive disorder can cause difficulty to concentrate and lack of interest in daily activities (e.g. anhedonia). However, other shits such as guilty feelings, appetite/weight loss and sleep disturbances can be seen. And also you wouldn't have the clinical features

A 65 five year old woman comes into the clinic complaining of progressively worsening gait disturbances over the last 2 years. She had a history of minor head trauma. The patient has difficulty concentrating, forgetfulness and loss of interest in daily activities for the last 12 months. She has a recent onset of urinary incontinence for the past 6 weeks. The patient has no tremor, visual changes, headaches, or nausea/vomiting. Her minimental examination is 20/30 where she does poorly at executive function tasks. On physical examination she has hyperreflexia of lower extremities and slow low rising step gait disturbances. CT shows enlargement of all ventricles. The patient is mostly suffering from which of the following? -Alzheimer's disease -Frontaltemporal dementia -Parkinson -Major depressive disorder -Normal pressure hydrocephalus -Obstructive hydrocephalus

This patients has normal pressure hydrocephalus cause by decreased absorption of CSF by the arachnoid villi. Urinary is controlled by 3 things: 1) Sacral micturition center - located in S2-S4 responsible for bladder contraction via parasympathetic innervation. 2) Pontine micturition center - located in the pontine reticular formation. It coordinates the relaxation of external urethral sphincter with detrussor contraction during voiding 3) Frontal lobe regulate this process by inhibition of sacral. -In NPH, patients enlarged ventricles impinge the corona radiata (descending cortical fibers) that transmit inhibitory signal to the sacral micturition center. As the disease progresses, lack of inhibition will cause uncontrolled micturition, aka urge incontinence. Bladder fills up and empty reflexively. The patient has no sensation of fullness and no control over bladder function. Voluntary relaxation of urethral sphincter is however intact.

A 65 year old caucasian male comes to the clinic complaining of urinary incontinence, gait disturbances and poor memory. MRI reveals enlarged ventricle without cortical atrophy (enlarge sulci). Urinary incontinence is most like due to.. -stretching of the descending cortical fibers -stretching of the cerebellar inhibitory fibers -impair basal ganglia -impair reticular formation -spinal cord damage

The sciatic nerve descends down the posterior thigh and divides into the tibial and common peroneal nerve, at the proximal popliteal fossa. From here, the common peroneal nerve travels laterally to enter the anterior compartment of the leg, passing superficially around the head and neck of the fibula. Etiology -Blunt trauma to the lateral aspect of the leg can cause a fibula neck fracture injuring the nerve. -Nerve can also be injured from external pressure d/t prolonged immobility. Clinical presentations -Equinovarus posture (plantar flexed/inverted) d/t paralysis of the peroneus longus and brevis (eversion of foot), the tibialis anterior (dorsiflexion) and extrinsic extensor of the toes. -Numbnesss/lost of sensation to the lateral part of the leg and dorsum of the foot. -The classic gait characteristic is the "foot drop." When patient lift his foot up, because he cannot dorsiflexed, the toes will point to the ground causing him to lift the foot higher. When landing with the same foot, he would slap the floor d/t the inability of patient to gently lower the forefoot up heel strike. Isolated lesion to the obturator nerve is rare. It is responsible for thigh adduction and sensation to a small area of the medial thigh. Superficial peroneal nerve innervates the peroneus longus and brevis responsible for foot eversion. It is also responsible for sensation over the lateral leg and dorsum foot. This is most likely no the man's site of lesion because of his inability to dorsiflex suggesting that this a common peroneal lesion because the deep peroneal is responsible for dorsiflexion of the foot The sural nerve is pure sensory responsible for sensation over the posteriolateral leg and lateral foot. The tibial nerve is responsible for plantarflexion and inversion of the foot and sensation to the posterior leg and sole of foot.

A 65 year old man comes to the clinic complaining of right leg weakness and numbness. He was recently discharged from the hospital where he stayed for a couple of weeks in the ICU under sedation. Neurological examination shows inability to evert right foot. He also has numbness over the lateral part shin and dorsum of foot. When asked to walk across the room, the patient right foot lifts higher than his left, and the right foot slaps the ground with each step. Which of the following nerves is injured? Common peroneal Obturator Superficial peroneal Sural Tibial

This patient is taking an analog of dopamine which binds to D1 receptor on the striatum increasing its activity to send out inhibitory GABA signal to the GPi, which has GABA inhibitory projection to the VA/VL nuclei of the thalamus. This ultimately leads to a disinhibition of the thalamus by GPi causing him to have excessive body movements. Because of this worsening side effect, he is reducing his medication. But, this causes his freezing episodes because without dopamine, GPi is constantly activated by the subthalamic nucleus to release inhibitory GABA onto the VA/VL nuclei of the thalamus. Reduced activity of the thalamus and its projections will lead to bradydyskinesia and rigidity. This patient would benefit from high frequency deep brain stimulation targeted at suppressing neuronal activity to the *subthalamic nucleus or the globus pallidus interna.* High frequency stimulation will inhibit these nuclei that result in a less inhibited thalamus (disinhibited) and improved motility.

A 65 year old man is taking levodopa/carbidopa for ten years since he was diagnosed with Parkinson. The drugs were successful in treating his Parkinson symptoms but for the last 7 months, he has developed "freezing" episodes characterized by sudden loss of mobility. The tremors worsened after reducing his medication d/t excessive body movements. He is interested in discussing surgical options. This patient would most likely benefit from high frequency deep brain stimulation targeted at suppressing neuronal activity to which of the following structures? a. caudate nucleus b. globus pallidus externa c. putamen d. red nucleus e. subthalamic nucleus f. ventral intermediate nucleus of the thalamus

This is Lambert-Eaton an autoimmune disease affecting the presynaptic calcium channel that is usually associated with small cell lung cancer. This is symptomatically similar to myesthenia gravies, however key differences are proximal weakness that improves with muscle use, can cause autonomic symptoms (dry mouth, impotence) and improves with muscle use. Symptoms don't improve with organophosphate administration. Nerve stimulation study will show an incremental response. They feel better as their muscles are being used. -Segmental myelin degeneration is Guillain Barre -Antibodies against ACh receptor is myesthenia gravis. Nerve stimulation study will show decremental response. Associated with thyoma. -perfifascicular muscle inflammation is associated with dermatomyositis. -Medication induced motor atrophy is associated with corticosteroid use.

A 65 year old man who was recently diagnosed with lung cancer says he has trouble getting up from his chair. Physical examination shows hip girdle weakness. Electrophysiological study shows remarkable muscle improvement on repetitive motor innervation. What is associated with his symptoms? -segmental myelin degeneration -antibodies against Ca channel -antibodies against ACh receptor -medication induced motor atrophy -perifascicular muscle inflammation

Myasthenia gravis is an autoimmune disease where antibodies attack the Ach receptors on the post ganglionic membrane of the neuromuscular junction. Patients often present with fluctuating weakness that worsens over the course of the day and most often involve the extraocular muscles (e.g. diplopia and ptosis) and bulbar muscles (e.g. muscle of mastication and swallowing). -Pyridostigmine is a long acting anti-AChesterase inhibitor use to treat myasthenia gravis, it however does not cross the CNS. -Myasthenia gravis can worsen in two ways: 1. if the patient is undertreated leading to a myasthenia crisis where there isn't enough ACh to bind to the decreased number of ACh receptors. The pyridostigmine dosage should be increased for these patients. Edrophonium should be given for immediate relief of symptoms but it is not given for long term since it is a short acting AChesterase inhibitor mostly use to diagnosed myasthenia gravis (aka Tensilon test). 2. this one is rare and it is also known as cholinergic crisis, where patients have in appropriately high dose of ACHesterase inhibitor leading to excessive amount of ACh that can result in muscle refractory to impulses. Lower the dosage should be treatment plan. -Atropine is a muscarinic antagonist use to treat AChE (organophosphate) overdose and pupil dilation. They do nothing with nicotinic receptors and is not use to treat myasthenia crisis. -Pralidoxime is use in organophosphate poisoning by reversing both muscarinic and nicotinic receptors, by regenerating the AChE at the NMJ.

A 66 year old male comes into the office complaining of diplopia, that worsens as the day goes on. Physical examination shows ptosis of the right eye. Patient admits to taking pyridostigmine for a condition that seems to be working for a couple of years. Edrophonium was given and his symptom got better. What should be the next thing we should do for this guy? -add atropine -stop pyridostigmine -change long term therapy to edrophonium -increase dosage of pyridostigmine -give pralidoxime

This patient is exhibiting hemiballismus of the right arm, thus there is a lesion in his left subthalamic nucleus most commonly caused by a lacunar stroke (risk factors DM and HTN). Subthalamic lesion will decrease GPi inhibition on thalamus = excessive movement. The movement usually involve the proximal limb with large amplitude flinging motion Caudate nucleus degeneration is associated with Huntington's disease, which is characterized by insidious onset of chorea (small amplitude flinging motion of the distal limb), dementia and behavioral abnormalities. Lacunar stroke can affect the internal capsule, but these patients will present with contralateral pure motor loss or contralateral sensorimotor loss. Atrophy of lentiform nucleus (e.g. globbus pallidus and putamen) is associated with Wilson's disease, which is characterized by liver disfunction (cirrhosis/hepatitis), psychiatric changes (depression, personality changes) and neurologic (movement disorder, dysarthria). Atrophy of the substnatia nigra is associated with Parkinson's. VPL is associated with contralateral complete loss of pain.

A 72 year old man presents to the emergency with complaints of involuntary movement of his right arm several hours ago. He was watching television when he throws the remote across the room. He has long standing history of DM and HTN. Does not drink, smoke or do elicit drugs. PE shows wild, large-amplitude flinging movements affecting proximal muscles of the arm. Which of the following area is affected in this patient? caudate nucleus subthalamic nucleus internal capsule lentiform nucleus substantia nigra ventral posterior thalamus

This elderly patient is most like suffering from lobar hemorrhage d/t cerebral amyloid angiopathy. Beta-amyloid deposition on small to medium size arteries resulting in wall weakness and predisposition to rupture. These amyloid are close to that of Alzheimers, not like those seen in systemic amyloidosis. This is the most common cause of lobar hemorrhage in patients over 60 years of age. Hemorrhage tends to be recurrent and most often involve occipital and parietal lobes. -Occipital lobe is associated with homonymous hemianopia. -Parietal lobe is associated with contralateral hemisensory deficit. -Frontal lobe is not as common but can arise causing contralateral hemiparesis.

A 75 year old is brought to the emergency with sudden vision problem and right sided hemisensory loss. While he's in the emergency room, his symptoms got worse and he started to have headaches. Head CT reveals multiple, small lobar hemorrhage of varying ages in the occipital and parietal areas with medium size acute bleeding in the left parietooccipital lobe. Two years ago patient had a sudden weakness of the arm. CT scan then showed small left frontal lobe hemorrhage. He has no head trauma and does not use anticoagulants. This patient most likely suffers from what?

A primary structure of protein consists of amino acids linked together by a covalent peptide bond. Primary structure can be folded into secondary structures in alpha-helical or beta-pleated sheet conformation via hydrogen bonds (the major stabilizing bond in secondary structure). Therefore breaking and reforming hydrogen bonds are essential to the conversion of beta-pleated sheets into alpha-helical structures. In Alzheimer patients, amyloid-beta protein losses its alpha-helical configuration and adopting a beta-pleated sheet structure making the protein more insoluble increasing the likelihood of aggregation leading to Alzheimer. Thus aggregation of beta-pleated sheets are the primary components of the extracellular senile plaques seen in Alzheimer patients. Tertiary structures are secondary structures that are folded and stabilizes by many forces including, ionic bonds, hydrophobic interaction, disulfide bonds (strong covalent bond between sulfur group of two cysteine that enhances resistance to denaturing) and the other two previously named mention bonds present in primary and secondary structures.

A group of Alzheimers researchers noticed a particular protein isolated form patients has abnormally high amount beta-pleated sheet conformation. A new medication is now being engineered to alter the protein to a more alpha-helical structure. The conformation change is a result of altering which of the following? Ionic interactions Hydrophobic interactions Hydrogen Bonds Peptide Bonds Disulfide Bonds

This is a shwannoma, which most commonly present at the cerbellowpontine angle. The three CN nerves usually affected are: -CN V: Paralysis of muscles of mastication and disturbance to the afferent limb of the corneal reflex. -CN VII: facial drooping whole face (at facial nucleus not UMN lesion), lack of anterior 2/3 taste, lack of lacrimation and salivation and hyperacusis d/t paralysis of stapedius. -CN VIII: sensori hearing loss, ringing, balance problems, vertigo and nystagmus. -Above the sellar diaphragm is associated with craniopharyngioma that is derived form the Rathke pouch. Patients will often present with pituitary and/or hypothalamic disfunction. Biltemporal heminanopia. Also, pituitary adenoma. -Germ cell tumors usually arise from the pineal gland located at the dorsal midbrain. Patients will present with non-communicating hydrocephalus and Parinaud syndrome (upward gaze palsy). -Lateral cerebral convexity (at falcine/parasaggital region) is near the meninges, thus tumors found here are most likely meningioma. Present with focal deficit. -Posterior fossa (aka cerebellum) are associated with medulloblastoma, pilocytic astrocytoma, hemangioblastoma. Cerebellar dysfunction. -Ependymoma derives from ependymal cells (CSF production so near ventricles) usually arises in 4th ventricle causing hydrocephalus. -Oligodendroglioma are most often found in the frontal lobe. -Glioblastoma multiforme grade IV astrocytoma can cross corpus callosum (butterfly glioma).

A patient has ringing and loss of hearing in her left ear. Physical examination shows decreased sensation to left side of the face, asymmetric smile and no afferent/efferent corneal response. Where is the lesion? -Above sellar diaphragm -between cerebellum and lateral pons -Dorsal midbrain -Lateral cerebral convexity -Posterior fossa -4th ventricle -Frontal lobe -Both cerebral hemisphere

Schwannomas are peripheral nervous system tumors from schwann cells. It is characterized microscopically as being biphasic, will areas of highly cellularity intermixed with areas of low cellular myxoid region. The high cellularity area are composed of spindle cells that form palisading pattern with interspersing nuclear free zone called Verocay bodies. -These tumors are S-100 psoitive d/t their neural crest cell origin. -The transition between oligodendrocytes and schwann cells are literally millimeters apart, thus schwannomas can occur in the cranial vault and cranial canal. These tumors can arise at any cranial nerve except for CN III which is served by oligodendrocytes. -The most common area affected is classically found at the cerebellopontine angle, thus classical presentations are acoustic neuromas including tinnitus, vertigo and hearing loss. -Glioblastoma is a highly malignant primary brain tumor that has bizarre appearing glial cells with pseudopalisading necrosis, mitotic figures, and abundant neurovasculization and hemorrhage. It commonly occurs in the frontotemporalparietal white matter and grows along the white matter tract that can cross the corpus callosum (butterfly glioma). Since it is from an astrocyte origin, it can be stained by GFAP. -Meningioma are typically slow growing, extra-axial tumor often arise in convexities of hemisphere (near surfaces of brain) and parasagittal region from mengioepithelial cells of the arachnoid. Meningiomas are characterized histologically by spindle cells concentrically arranged in a whorled pattern and psammoma bodies (laminated calcifications). -Opticglioma are glioma affected the optic nerve. It is often found in association with NF 1. Histologically, optic gliomas have immature astrocytes with microcystic degeneration and Rosenthal fibers (elongated or corkscrew intracytoplasmic eosinophilic bundles).

An intracranial mass was taken out of a 26 year old male patient. The mass is composed of elongated cells with regular oval nuclei. A biphasic pattern was seen with areas of dense cellularity interspersed with areas of less myxoid regions. The cells show S-100 immunoreactivity. What is the diagnosis? Glioblastoma Meningioma Metastatic lung carcinoma Opticglioma Schwannoma

The cerebellum comprises of: -anterior lobe -posterior lobe -flocculonodular lobe - inside posterior lobe closest to the brain stem. Neurologists like to divide the cerebellum up into longitudinal sections: -Central is vermis: Associated with truncal and proximal muscles -Intermediate hemisphere (paravermis): more truncal and proximal muscles -Lateral hemisphere: associated with limb movements -All input (mossy and climbing fibers) enters cerebellar cortex where it is relay to the deep cerebellar nuclei (via purkinje fibers) where it will get integrated and sent out. The deep nuclei from medial to later are (Fast Gerbil Exercise Daily): Fastigial Globose Eboliform Dentate (Globose and Eboliform are sometimes grouped together as the interposed nuclei) -The major output of the cerebellum is the brachium conjunctivum (AKA superior cerebellar peduncle) that goes to the contralateral ventral lateral thalamus that relays information to the premotor cortex and the supplemental motor cortex to initiate fine smooth movements. The cerebellum receives input from 3 places: 1) Vestibular (vestibulocerebllum) signal enters cerebellar cortex where it get relay signal to the *fastigial nuclei* of the vermis and flocculonodular where it gets integrated and sent out to the VL thalamus to the vestibular nuclei to regulate balance and eye movement. -Lesion to the vermis and flocculonodular lobes will cause patient to have disequilibrium and nystagmus especially when looking towards the side of lesion. -The most common cause of flocculonodular lobe lesion is medulloblastoma in childhood. 2) Spinal Cord (spinocerebellum): is integrated and relayed by *fastigial and interposed* nuclei of the vermis and para-vermis (intermediated hemisphere, respectively. *This is motor execution.* - Lesion will cause postural instability, hypotonia, pendulum knee jerk reflex and slurred/slowing of speech. -Anterior lobe syndrome (anterior vermis) affects the legs causing patients to have ataxia/dystaxia of the legs (even when trunk is supported) presenting as broad-base staggering gait. Most common cause is thiamine deficiency from chronic alcoholism leading to degeneration of the cerebellar cortex, starting at the anterior vermin. 3) Cerebrum (cerebrocerebellum): is integrated and relayed by the *dentate nucleus* located in the lateral hemisphere. *This is for motor planning.* -Lateral cerebellar lesion (lateral hemisphere/dentate nucleus) will cause patient to be unable to coordinate movement (w/ respect to timing and rate of movement). They will have trouble starting and stopping movement as well as dysmetria (inability to control speed, distance and power of movement) and intentional tremor.

Anatomy of the cerebellum and signaling pathways. How can you think about the cerebellum in a functional context?

Muscle and Spinal Cord: -There are two types of muscle fibers: 1) Extrafusal - These are the typical muscle fibers that we know about. They are innervated by efferent *alpha* motor neuron from the anterior horn. 2) Intrafusal - These are proprioceptors imbedded within the muscle tissue forming *muscle spindles* that have efferent *1a* neurons synapsing with the *alpha* motor neurons. -When a muscle stretches, its spindles sense the length and velocity of the stretch and relay signal to the anterior horn via the 1a afferent neurons. -1a afferent neurons synapse with the efferent alpha motor neurons of that muscle to excite the extrafusal muscle fibers. -This enables us to know how much contractile force is needed to counteract the stretch. Golgi tendon organ senses the tension of the the muscle. It has 1b neurons that relay signal to the posterior horn that synapse with inhibitory neurons to stop action of the alpha motor neuron. -When you and your friend are picking up a very heavy table together and he suddenly lets go of the table, your golgi tendon organ will sense this tension and make you let go and drop the table. Gamma loop: -The cerebral cortex also has excitatory neurons synapsing with the alpha motor neurons and the gamma neurons. The latter neurons synapse with the muscle spindle to modulate its sensitivity to stretch by increasing the spindle's 1a afferent neurons resting potential increasing the probability of an AP, thus increasing the stretch-sensitivity.

Describe Reflex Arc, Gamma Loop and Golgi Tendon Organ

When a decision is made to move, the striatum receives excitatory glutamatergic input from virtually all regions of the cerebral cortex. In addition to the cortical input, the striatum also receives input from dopamingergic neurons of the SNpc (pars compacta). The dopamine input however serves mainly as modulator of transmission from the cortex to the striatum. Dopamine binds to two distinct receptors based on their activity on adenyl cyclase (AC) in response to dopamine agonist. -D1 receptors are found in the direct (Go) pathway of the striatum. Stimulation will increase striatal response to the *internal segment of the GP* after cortical input. -D2 receptors are found in the indirect (Stop) pathway. This pathway inhibits AC activity and dececreases the effect of cortical input to striatal neurons that project to the *external segment of the GP.* Direct pathway: -When striatum is stimulated by dopamine and glutamine, it releases GABA, which inhibits the GPi and SNpr. -Normally GPi and SNpr neurons function to form inhibitory synapse with the VA/VL (ventral anterior/ventral lateral) nuclei of the thalamus via GABA. -But now that GPi and SNpr are inhibited by the striatum, this dampens the inhibitory signal to the thalamus enabling it to send excitatory signal (glutamate), to the cerebral cortex to perform the desired movement. Indirect Pathway: -Stimulatory glutamate neurotransmitter released by the cortex activates the striatum. Dopamine binds to D2 which has inhibitory GABA input to the GPe. -The normal role of GPe is to inhibit the subthalamic nucleus via GABA to decrease the amount of glutamate it sends to activate the GPi, and as before, when GPi is inhibited, it cannot send GABA to the VA/VL nuclei of the thalamus to inhibit movement. -So when D2 is activated, it inhibits GPe which cause a disinhibition to the subthalamic nucleus enabling it to send more glutamate to activate the GPi. When GPi is activated, there will be inhibition of movement from GABA acting on the VA/VL. Therefore, Dopamine acts as an inhibitory and excitatory neurotransmitter.

Describe dopamine and its function in the Cortico-striatal-thalamo cortical circuit.

This is in charge of pain. -Bipolar neurons at the dorsal root ganglia relay pain signal to the first order neuron located in the dorsal horn, which immediately cross over via the anterior white commissure and ascends as the anterior lateral spinal tracts. -They ascend and synapse with VPL neurons that ascend as the posterior limb of the IC to their respective area in the somatosensory cortex. Clinical correlation: -Spinal lesion involving the ALS result in a loss of pain and temperature sensation on the contralateral side of the body beginning one or two levels caudal to the lesion. -Syringomyelia produces bilateral sensory losses restricted to the adjacent dermatomes because of damage to the anterior white commissure. -Vascular lesions in the lateral medulla (PICA syndrome) or lateral pons (AICA occlusion) will result in a loss of pain and thermal sensation over the entire contralateral side of the body as well as on the ipsilateral face, coupled with other motor and/or sensory deficits based on damage to structures these vessels serve. *note that the ALS and PC-ML systems are separated in the medulla and thus have different vasculature supply. However they are adjacent to each other in the midbrain therefore they have similar blood supply. Consequently, -Medullary lesions will not result in deficits related to both pathways, while a lesion in the midbrain may result in deficits related to both pathways thus patients willl have contralateral loss of pain, thermal, vibratory and discriminative touch sensation on the body, excluding the ehad.

Describe the anterolateral system pathway

As you move rostrally the amount of gray matter compared to white matter will began to decrease, thus the most amount of white matter is going to be located in the cervical region, and the most amount of gray matter will be seen in the sacral area. The spinal cord tends to take an ovoid shape as it ascend rostrally. Thoracic and lumbosacral cords have large ventral horn. The thoracic and early lumbar cord has a characteristic lateral horn (sympathetic ganglion). Distinct thoracic and early lumbar cross section from one another by the presence of the cuneate fasciculi which appears at T7.

Describe the differences in spinal cross section between the sacral, lumbar, thoracic and cervical veterbrae.

In charge of body's touch, proprioception and vibration. -Posterior root ganglions have bipolar neurons that relay signal to the posterior column to synapse with cuneate (arm)/gracile (leg) fasiculi. -These fibers ascend rostrally towards their respective nuclei in medulla and synapse with their respective nuclei, decussate to the contralateral side and continue as the medial lemniscus towards the VPL of the thalamus. -There they synapse to the final 3rd order neuron which leaves the VPL and ascend as the posterior limb of the internal capsule to their respective places in the cortex. Clinical -Damage to posterior column fibers on one side of the spinal cord results in ipsilateral loss of vibration, proprioception and discriminative touch below the level of the lesion. -Lesion rostral to the decussation such as the medial lemniscus will result in contralateral losses that include the entire body besides the head.

Describe the posterior column-medial lemniscus system

The cerebellar vermis modulates axial/truncal posture and coordination via the connection of the descending motor tracts (anterior corticospinal, corticobulbar, reticulospinal and tectospinal tracts). If there is a lesion to this area, you will get a wide gait and truncal ataxia. Patients may develop nystagmus and vertigo d/t involvement of the inferior vermis & floccunodular lobe (via the vestibular nuclei and medial longitudinal fasciculus) -Limb dysmetria is cause by lesion to the lateral hemisphere of the cerebellum d/t involvement of the *lateral descending motor* neurons (e.g lateral corticospinal tract, rubrospinal tract). This lateral hemisphere of the cerebellum lesion will also cause intentional tremors. -Complete ptosis from central lesion can be cause by injury to the occulomotor nerve fibers within the upper midbrain and it is usually associated with contralateral hemiparesis d/t adjacent corticospinal tract involvement (e.g. weber syndrome) -Dysphagia is usually cause by lesion in the brainstem to CN IX, X and XII and/or their nuclei. Cerebral cortical and subcortical lesions affecting the corticobulbar tract will cause this. -Hemiparesis is cause by lesion to the corticospinal tract in the cerebrum and brainstem, NOT cerebellar. -Resting tremors are associated with Parkinson d/t the damage of the substantia nigra and its projections to the striatum. Rubral tremors occur at rest and goal oriented activity and is associated with lesion to the cerebellothalamic pathways (midbrain, substantia nigra and superior cerebellar peduncle).

Dude has vermis lesion from a tumor with no midline shift or mass affect. What is his physical symptoms going to be? a. complete ptosis b. dysphagia c. truncal ataxia d. hemiparesis e. limb dysmetria f. resting tremors

Saccadic eye movement - Left frontal eye field (BA 8) sends descending signal towards the contralateral (right) PPRF (parapontine reticular formation). -PPRF sends signal to the ipsilateral (right) abducens nucleus. -Abducens nucleus does two things: 1) It sends signal towards the lateral rectus on the ipsilateral side (right eye) to look right. 2) It also sends signal towards the contralateral (left) occulomotor nerve by ascending the MLF (medial fasciculus) to tell the left eye to abduct (look left). MLF lesion: -Signal from abducens cannot go to the contralateral occulomotor to innervate the medial rectus. Example: Patient has left MLF lesion. -Left occulomotor cannot receive signal from right abuducens therefore, when you tell the patient to look right, the right eye will abduct (look right) while left eye would not move. -Convergence will be normal (different pathway) PPRF lesion -Abducens is not innervated so there would be no ipsilateral abduction lateral recuts and contralateral adduction of the medial rectus. Example: Patient has left PPRF lesion. -The patient's left abducens would be compromised, thus the left lateral rectus and right medial rectus would not contract. So if you tell that person to look left, both of her eyes would not move. -aka, conjugate horizontal gaze to the side of the lesion would be interrupted. PPRF and MLF lesion: -PPRF will lesion will cause patient the inability to look towards the side of the lesion. -MLF lesion would cause the patient the inability to look towards the side of the lesion. Example: Patient has left PPRF and MLF lesion -When you tell patient to look left (towards the lesion) he/she will not be able to do so. -When you tell the patient to look right, only the right eye would move, while the left eye would stay fix.

Eye Movement

Monoocular scotoma is a partial lesion in the optic nerve, optic disc or retina. Etiology: optic neuritis, macular degeneration Right anopia is a lesion to the right optic nerve. Etiology: retinal artery or central retinal vein occlusion. Bitemporal hemianopia is a lesion to the optic chiasm. Etiology: space occupying lesions (e.g. pituitary tumor, cranipharyngioma or aneurysm to the Communicating ACA). Right nasal heminopia is cause by right peri-chiasmal lesion. Etiology: calcification of the internal coratid impinging on the uncrossed lateral fibers. Left homonomous heminopia is cause by either lesion to the right optic track or the optic radiation. Etiology: a. optic tract = occlusion of the anterior choroidal artery. b. optic radiation = occlusion of the middle cerebral artery or lesions involving the posterior branch of the internal capsule. Left homonomous superior quadrantanopia is cause by lesion to the right temporal lobe affecting the Meyer's Loop. Etiology: Lesion or stroke involving the temporal lobe. Left hemonomous inferior quadrantanopia is cause by lesion to the right parietal lobe affecting the dorsal optic radiation. Etiology: lesion or stroke involving the parietal lobe. Left homonomous heminopia with macular sparing is lesion to the visual cortex (occipital lobe). Etiology: Occlusion to the posterior cerebral artery, macula sparing because it is supplied by the MCA.

For the following visual field defects name the location of the lesion and the etiologies. -Monoocular scotoma -Right anopia -Bitemporal heminopia -Right nasal heminopia -Left homonomous heminopia -Left homonomous superior quadrantanopia -Left homonomous inferior quadrantonopia -Left homonomous heminopia with macular sparing

Middle cerebral artery Left: Aphasia (Broca/Expressive, Werneke/receptive), contralateral weakness (UMN lesion spares forehead) and loss of sensory. Right: Along with contralateral weakness and loss sensation. No aphasia but anosognosia (lack of insight) and spatial neglect of contralateral side. ACA: contralateral weakness and loss of sensation affecting the feet and perineum. Can also cause significant behavioral changes, primitive reflex and urinary incontinence d/t prefrontal cortex being messed up. PCA: contralateral hemianopia with macular sparing. Saccular aneurysm is occlusion of the communicating arteries of PCA and ACA. Communicating ACA obstruction will lead to optic chiasm obstruction causing bitemporal hemianopia. Communicating PCA can affect CN III (down and out, ptosis and mydriasis). Basilar artery occlusion can damage pons which have the corticalspinal tract, corticalbulbar and paramedian tegmentum. Patients will be quadriplegic, facial muscle weakness and occulomotor deficit. AICA can cause lateral pontine syndrome. -Ipsilateral loss of pain and sensation (CN V nucleus) -Ipsilateral facial weakness (CN VII nucleus) -Ipsilateral hearing loss (CN VIII). -contralateral loss of pain and temperature -cerebellar dysfunction d/t spinocerebellar tract

How would lesion of MCA, ACA, PCA, Saccular aneurysm, basilar artery and AICA present?

Kinesin and dyenin are the motor components of the microtubule structure responsible for rapid axonal transportation using ATP hydrolysis. Kinesin is associated with anterograde transport (i.e. it moves vesicles and organelles towards the plus (+) end of the microtubule usually directed away from the nucles). Dyenin is associated with retrograde transport, it moves things towards the negative (-) end of the micro directly usually towards the positive (+) end. Nissl substance is neuronal RER. They are only located in the cell body, not axon. Intermediate filament are a half as small as microtubule (e.g. 23 > 8-10 nm). Dyenin also function in ciliary and flagella movement.

Kinesin and dyenin are major isolated from neural sample. These proteins are functionally associated with which of the following structures? Nissl substance Microtubules Lysosome Lipid membrane Nuclear membrane Intermediate filament