Patho Chapter 20 disorders of brain function

classifications of brain tumors

*Benign- well-differentiated & histologically benign tumor may grow and cause death because of its location. Malignant- cancerous

generalized seizures

*TONIC-CLONIC "grand mal seizures" Vague warning (focal seizure) and experiences a sharp tonic contraction of the muscles with extension of the extremities and immediate loss of consciousness. Incontinence of bladder and bowel is common ABSENSE: Generalized, non-convulsive epileptic events (disturbances in consciousness) MYOCLONIC: Brief involuntary muscle contractions induced by stimuli of cerebral origin CLONIC: Loss of consciousness & sudden hypotonia TONIC: Sudden onset of increased tone, often associated with falling ATONIC: Sudden, split-second loss of muscle tone leading to slackening of the jaw, drooping of the limbs, or falling to the ground.

criteria for dx vegetative state

-absence of awareness of self and environment -inability to interact with others -absence of voluntary response -lack of language comprehension -hypothalmic and brain stem function to maintain life -bowel/bladder incontinence -preserved cranial nerve and spinal reflexes -condition has continues for more than 1 month

medical documentation of brain death

-cause and irreversibility of condition -absence of brain stem reflexes/motor response(pain) -absence of respiration with pco2 60 or more -justification for confirmatory tests

brain herniation

-cingulate: involves cerebral artery (leg weakness) -central transtentorial: invovles reticular activating system and corticospinal tract (altered LOC, decorticate posturing) -Uncal: involves cerebral peduncle, oculomotor nerve, posterior cerebral artery, cerebellar tonsil, respiratory center (hemiparesis, pupil dilation, visual field loss, respiratory arrest)

hypoxia ischemia

-deprivation of oxygen within maintained blood flow -reduced or interrupted blood flow *focal cerebral ischemia: (localized injury) stoke *global cerebral ischemia: (inadequate blode flow to the brain) MI

coup contra-coup injuries

-direct contusion of the brain at the site of force -rebound injury on the opposite side of the brain brain floats freely in csf, blunt force accelerates the brain and then it decelerates abruptly hiding the skull

signs of diminished LOC

-earliest signs: inattention, mild confusion, disorientation, blunted response -with further deterioration: markedly inattentive/lethargic/agitated, may progress to become obtunded- respond to only vigorous/ noxious stimuli

classifications of skull fractures

-simple or linear: break in the continuity of the bone -comminuted: splintered or multiple fx line -depressed: bone fragments embedded in brain tissue -basilar: fracture at base of skull

blood flow to the brain

-two internal carotid arteries anteriorly -vertebral arteries posteriorly internal carotid and vertebral arteries communicate together through the circle of willis -controlled by autoregulation, sympathetic stimulation, o2, co2, hydrogen

seizures

Abnormal behavior caused by an electrical discharge from neurons in the cerebral cortex. signs and symptoms that vary according to the site of neuronal discharge in the brain Manifestations generally include sensory, motor, autonomic, or psychic phenomenon Proposed Causes: genetic mutations Alterations in cell membrane permeability or distribution of ions across the neuronal cell membranes. Decreased inhibition of cortical or thalamic neuronal Neurotransmitter imbalances such as acetylcholine excess

risk factors and deficits of stroke

Age, sex, race, Family history HTN, Smoking, DM, a-fib, Asymptomatic carotid stenosis Sickle cell disease, Hyperlipidemia Motor deficits are the most common followed by language, sensation and cognition Dysarthria and Aphasia

aneuysmal subarachnoid hemorrhage

Bleeding into the subarachnoid space Causes: Congenital defect Acute increases in ICP Cigarette smoking Hypertension Excessive alcohol intake

infections of the CNS

By structure Meninges: meningitis Brain parenchyma: encephalitis Spinal cord, myelitis Brain and spinal cord: encephalomyelitis By type of invading organism: Bacterial, viral, or other

compensatory mechanisms

CSF and blood volume compensate for changes in ICP -initial increase in ICP is buffered by movement of CSF to spinal subarachnoid space and increased reabsorption

ischemic stroke

Caused by an interruption of blood flow in a cerebral vessel and are the most common type of strokes, accounting for 70% to 80% of all strokes

hemorrhagic stroke

Caused by bleeding into brain tissue usually from a blood vessel rupture caused by hypertension, aneurysms, arteriovenous malformations, head injury, or blood dyscrasias

postconcussion syndrome

Concussion refers to "an immediate and transient loss of consciousness accompanied by a brief period of amnesia after a blow to the head." Recovery usually takes place in 24 hours Mild symptoms may persist for months: Headache, Irritability, Insomnia Poor concentration and memory

levels of conciousness

Confusion Delirium lethargy: drowsy, responds then falls back asleep -Obtundation: opens eyes and looks at you but is slow and confused (decreased alertness of/to environment) -Stupor: response to verbal stimuli slow or absent, responds to pain but lapses back to unresponsive without stimuli (unaware of environment) -Coma: unarousable, eyes closed, no pain response Brain death Persistent Vegetative State: coma like with open eye but no awareness

Status epilepticus

Continual seizures, Do not stop spontaneously Many types If untreated or not stopped can lead to death due to respiratory failure

The nurse is caring for a trauma victim with head injury. Which factor will affect the cerebral blood flow?

Decreased level of oxygen

Which type of hematoma usually results from a tear in an artery associated with a skull fracture?

Epidural hematoma

stroke warning signs : FAST

Face: droop? Arm: one arm drift down? Speech: slurred? Time: call 911 if any of these signs

hemodynamic effects of av malformation

First, blood is shunted from the high-pressure arterial system to the low-pressure venous system without the buffering advantage of the capillary network The draining venous channels are exposed to high levels of pressure, predisposing them to rupture and hemorrhage Second, the elevated arterial and venous pressures divert blood away from the surrounding tissue, impairing tissue perfusion

seizure classification

Focal seizure: Seizure begins in a specific or focal area of one cerebral hemisphere Generalized seizure: Begins simultaneously in both cerebral hemispheres.

encephalitis

Generalized infection of the parenchyma of the brain or spinal cord, Local necrotizing hemorrhage Progressive degeneration of nerve cell bodies Prominent edema *Common causes are HSV and West Nile virus* Characterized by nuchal rigidity, headache, & fever. Transmission: Ingestion, Mosquito, Rabid animal

The nurse is planning an inservice on hypoxia versus ischemia in brain-injured clients. The nurse should include which of the following?

Hypoxia produces a generalized depressive effect on the brain

meningitis

Inflammation of the pia mater, arachnoid, CSF-filled subarachnoid space. Inflammation spreads rapidly dt CSF circulation. 2 types Bacterial, viral Bacterial: Most by S.pneumoniae or N. meningitidis *Neonates caused by Group B Strep- which is why we do GBS testing at the end of pregnancy- if the pregnant woman is positive we treat her when she goes into labor to prevent the baby from becoming infected* Characterized by nuchal rigidity, photophobia, Feve, chills, HA, back, abdominal, extremity pains; n/vomiting Tx is immediate- delayed treatment can result in poor outcomes

clinical manifestations of brain tumors ependymomas meningiomas primary CNS lymphomas

Intracranial tumors give rise to focal disturbances in the brain function and increased ICP. Focal disturbances occur because of brain compression, tumor infiltration, disturbances in blood flow and brain edema. General s/s: Headache, nausea, vomiting, mental changes, papilledema, visual disturbances, alterations in sensory and motor function, and seizures.

A patient's emergency magnetic resonance imaging (MRI) has been examined by the physician and tPA has been administered to the patient. What was this patient's most likely diagnosis?

Ischemic stroke

seizure classification list

Partial Seizures -Simple partial seizures -Complex partial seizures -Partial seizures evolving to secondarily generalized seizures Unclassified Seizures -Inadequate or incomplete data Generalized Seizures -Absence seizures -Atonic seizures -Myoclonic seizures -Tonic seizures -Tonic-clonic seizures

The nursing assistant reports to the registered nurse that a client with a brain tumor has a blood pressure of 180/100 and a pulse of 50. Which of the following is the correct nursing intervention?

Report to physician the client's signs of increased intracranial pressure.

Epilepsy

Seizures may be caused by alterations in cell membrane permeability or distribution of ions across the neuronal cell membranes decreased inhibition of cortical/thalamic neuronal activity structural changes alter the excitability of neurons Neurotransmitter imbalances such as an acetylcholine excess or γ-aminobutyric acid (GABA, an inhibitory neurotransmitter) deficiency have been proposed as causes Certain epilepsy syndromes have been linked to specific genetic mutations causing ion channel defects

convulsion

Specific seizure involving the entire body

The MRA scan of a client with a suspected stroke reports ruptured berry aneurysm. The nurse plans care for a client with which of the following?

Subarachnoid hemorrhage

epilepsy

Syndromes of associated seizure types: EEG patterns Exam findings Hereditary patterns Precipitating factors

A patient has been diagnosed with a cerebral aneurysm and placed under close observation before treatment commences. Which of the following pathophysiologic conditions has contributed to this patient's diagnosis?

Weakness in the muscular wall of an artery

hydrocephalus

abnormal increase in csf volume in part or all of the ventricular system=enlargment of csf compartment types communicating: decreased absorption of csf noncommunicating: overproduction of csf

manifestations of global brain injury

alterations in sensory and motor function changes in level of conciousness rostral-to-caudal step wise progression: as the diencephalon, midbrain, pons, medulla are effected additional respiratory, pupillary, eye movement reflexes and motor signs become evident

types of hematomas

brain injuries can be catagorized as traumatic (concussion, contusion, diffuse axonal injury) *epidural: temporal area is fx, develops btw dura & skull *subdural: bleeding btw brain and dura dt tear in small bridging veins on surface of the cortex that connect down to dural sinuses -traumatic intracerebral hematomas: may be single or multiple, common in temporal or frontal may be associated with severe motion or a contusion that turned into a hematoma non-trumatic (stroke infection, tumor, seizure)

infants increased ICP

bulging fontanels cranial suture separation increased head circumference high pitched cry

signs of increased ICP

early recognition preserves brain function *EARLY: change in LOC, irritable, confused, pupillary change and decreased GCS, vomiting, seizures, HA *LATE: difficult to arouse, coma, posturing, fixed/blown pupils, ecg change *Cushings triad: systolic HTN with widening pulse pressure, bradycardia and respiratory depression

common pathways of brain damage

effects of ischemia excitatory amino acid injury cerebral edema injury due to increased ICP

intracranial pressure: 0-15mm

increased icp is common cause of injury: can obstruct cerebral brain flow, destroy brain cells, displace brain tissue, damage structures -cranial activity: 10% blood 10% CSF 80% brain tissue monro-kellie hypothesis of normalization of icp *influenced normally by intrathoracic pressure (coughing) or intrabdominal pressure (valsalva)

injury from excitatory amino acids

injury to neurons caused by over-stimulation of receptors for specific amino acids that act as excitatory neurotransmitter -causes: stroke, hypoglycemic injury, trauma to chronic degeneretive disorders (Huntingtons/Alzheimers)

LOC examination technique

lethargy: speak in a loud voice obtundation: shake gently stupor: apply light painful stimuli (nail bed, pinch) coma: repeated painful stimuli

focal and diffuse brain injuries

primary brain injuries include focal (contusion, laceration, hemorrhage) diffuse (concussion, diffuse axonal injury) secondary brain injuries are often diffuse or multifocal including edema, infection and hypoxia

types of brain injuries

primary/direct: damage is caused by impact, include diffuse axonal injury and the focal lesions of laceration, contusion and hemorrhage secondary injuries: damage results from subsequent brain swelling, infection and cerebral hypoxia often diffuse or multifocal, including concussion, infection and hypoxic brain injury

focal seizures

simple partial Seizures without impairment of consciousness or awareness Psychomotor Seizures with impairment of consciousness or awareness: Accompanied by automatisms: repetitive, nonpurposeful activities such as lip smacking, grimacing, patting, or rubbing clothing

signs and symptoms of cerebral aneurysm

small aneurysms are asymptomatic Large aneurysms may cause chronic headache, neurologic deficits, or both Other manifestations include signs of meningeal irritation, cranial nerve deficits, stroke syndrome, cerebral edema and increased ICP, and pituitary dysfunction Hypertension and cardiac dysrhythmias result from massive release of catecholamines triggered by the subarachnoid hemorrhage

tx and evaluation of brain tumors

surgery, irradiation, chemotherapy, MRI, CT, Electroencephalogram Visual field and fundoscopic examination Include physical and neurologic examinations

what causes injury to the brain

traumas, tumors, stroke, metabolic derangements, degenerative disorders

cerebral edema

vasogenic edema: occurs with conditions that impair function of blood brain barrier and allow transfer of water and protein from vascular into interstitial space cytotoxic edema: involves an increase in intracellular fluid interstitial cerebral edema: edema of the central white matter as in hydrocephalus affecting the brain