Differential Diagnosis: Nervous System

Infant Reflexes

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Strength Grading Scale

0 - no muscular contraction 1 - barely detectable trace of contraction 2 - active movement without gravity 3 - active movement against gravity (without resistance) 4 - active movement against gravity and some resistance 5 - active movement against full resistance (NORMAL)

Bilateral Small Pupils

1-2.5mm Suggest damage to sympathetic pathways in hypothalamus, or metabolic encephalopathy, a diffuse failure of cerebral function that has many causes, including drugs Light reactions normal

Nystagmus: Characteristics

1. Observe for nystagmus only within the field of full binocular vision to correctly identify 2. Nystagmus has both slow and fast phases, but is defined by its fast phase (if eyes jerk quickly to patient's left and drift slowly to right, patient said to have left-beating nystagmus) 3. Pendular nystagmus consists only of coarse oscillations without quick or slow components 4. Movement of nystagmus may occur in one or more planes (horizontal, vertical, rotary); plane of the movement, NOT direction of gaze, that defines this variable

Facial Paralysis: Causes

1. Peripheral lesion of CN VII, the facial nerve, anywhere from its origin in the pons to periphery in the face (ie. Bell's palsy) 2. Central lesion involving the upper motor neuron system between the cortex and the pons (ie. Left hemispheric CVA) *Distinguish these two by their different effects on the upper part of the face Lower part of the face is normally controlled by upper motor neurons located only on the oppsite side of the cortex. Left hemispheric damage to these pathways, as in a stroke, paralyzes the right lower face (right upper face continues to function well due to control by pathways from both sides of the cortex and remaining upper motor neurons on the right)

Reflex Grading Scale

4+ Very brisk, clonus 3+ Brisker than average 2+ Normal 1+ Diminished 0 Absent

Midposition Fixed Pupils

4-6mm Suggest structural damage in the midbrain

Pinpoint Pupils

<1mm Suggest hemorrhage in pons, or effects of morphine, heroin, or narcotics Light reactions seen with magnifying glass

Decerebrate Rigidity

Abnormal Extensor Response Jaws are clenched, neck is extended Arms adducted and stiffly extend at the elbows; forearms pronated, wrists and fingers flexed Legs are stiffly extended at the knees, with feet plantar flexed May occur spontaneously or in response to external stimuli Caused by lesion in diencephalon, midbrain, or pons; severe metabolic disorders like hypoxia or hypoglycemia may produce it

Decorticate Rigidity

Abnormal Flexor Response Upper arms are flexed and tight to the sides; elbows, wrists, and fingers flexed Legs are extended and internally rotated Feet are plantar flexed Posture implies destructive lesion of the corticospinal tracts within or very near cerebral hemispheres Unilateral - chronic spastic hemiplegia

Intention Tremors

Absent at rest and appear with movement, often get worse as the target gets closer Cause: Disorder of cerebellar pathways as in MS

Postural Tremors

Appear when the affected part is actively maintaining a posture Example: Fine rapid tremor of hyperthyroidism, tremors of anxiety and fatigue, benign essential tremor

Level of Consciousness: Lethargy

Appears drowsy but opens eyes and looks at you, responds to questions, and then falls asleep Technique: Speak to the patient in a loud voice

Level of Consciousness: Stuporous

Arouses from sleep only after painful stimuli, verbal responses are slow or absent, patient lapses into unresponsive state without stimulus, and there is minimal awareness of self or the environement Technique: Apply painful stimulus

Involuntary Movements: Chorea

Brief, rapid, jerky, irregular, and unpredictable Occur at rest or interrupt normal coordinated movements; face, head, lower arms, and hands are often involved Seldom repeat themselves Cause: Sydenham's chorea (with rheumatic fever), Huntington's disease

Involuntary Movements: Tics

Brief, repetitive, stereotyped, coordinated movements occurring at irregular intervals Example: Winking, grimacing, shoulder shrugging Cause: Tourette's and drugs

Facial Paralysis: CN VII (Left Sided) Central Lesion

Closing eyes: Right eye closes, perhaps with slight weakness Flat nasolabial fold Raising eyebrows: Right forehead wrinked, eyebrow raised Paralysis of lower face

Dysarthria

Defect in the muscular control of the speech apparatus (lips, tongue, palate, or pharynx) Words may be nasal, slurred, or indistinct, but the central symbolic aspect of language remains intact Cause: Motor lesions of the central or peripheral NS, parkinsonism, and cerebellar disease

Aphasia

Disorder in producing or understanding language Cause: Lesions in the dominant cerebral hemisphere, usually the left

Bilaterially Large Reactive Pupils

Due to cocaine, amphetamine, LSD, or sympathetic NS agonists

Bilaterally Fixed and Dilated Pupils

Due to severe anoxia and sympathomimetic effects, as seen after cardiac arrest; also from atropine-like agents, phenothiazines, and TCAs

Glasgow Coma Scale

Eye opening 1 - none 2 - to pain 3 - to speech 4 - spontaneous Motor response 1 - none 2 - extension 3 - flexor response 4 - withdrawal 5 - localizes pain 6 - obeys commands Verbal response 1 - none 2 - incomprehensible 3 - inappropriate 4 - confused 5 - oriented Total = 3-15; Score of 3-8 is considered comatose

Acute Ischemic Stroke

Ischemic brain injury begins with a central core of very low perfusion and irreversible cell death Core surrounded by ischemic penumbra - metabolically disturbed cells that are still potentially viable, depending on restoration of blood flow and duration of ischemia Most irreversible damage occurs in first 3-6 hours; therapies target 3-hour window

Dysphonia

Less severe vocal impairment in the volume, quality, or pitch of the voice Example: Hoarse or only able to speak in a whisper Cause: Laryngitis, laryngeal tumors, unilateral vocal cord paralysis (CN X)

Focal Seizures

Limited to one hemisphere Ictal onset site is consistent from one seizure to another

Disorders of Muscle Tone: Rigidity

Location of lesion: Basal ganglia system Description: Lead-pipe rigidity = increased resistance that persists throughout the movement arc, independent of rate of movement; Cogwheel rigidity = superimposed rachetlike jerkiness with flexion and extension of the wrist or forearm Cause: Parkinsonism

Disorders of Muscle Tone: Paratonia

Location of lesion: Both hemispheres, usually in the frontal lobes Description: Sudden changes in the tone with passive range of motion; sudden loss of tone that increases the ease of motion (mitgehen, moving with); sudden increase in tone making movement more difficult (gegenhalten, holding against) Cause: Dementia

Disorders of Muscle Tone: Flaccidity

Location of lesion: Lower motor neuron system at any point from anterior horn cell to the peripheral nerves Description: Loss of muscle tone (hypotonia), causing the limb to be loose or floppy; affected limbs may be hyperextensible or even flail-like; muscles are weak Cause: Guillain-Bare syndrome, initial phase of spinal cord injury (spinal shock) or stroke

Disorders of Muscle Tone: Spasticity

Location of lesion: Upper motor neuron or corticospinal tract systems Description: Increased muscle tone (hypertonia) that is rate dependent; tone is greater when passive movement is rapid and at the extremes of the movement arc, and less when passive movement is slow; during rapid passive movement, initial hypertonia may give way suddenly (spastic "catch") as the limb relaxes (known as "clasp-knife" resistance) Cause: Late or chronic stage of stroke

Aphonia

Loss of voice that accompanies disease affecting the larynx or its nerve supply

Focal Seizures without Impairment of Consciousness or Awareness: With autonomic symptoms

Manifestations: "Funny feeling" in epigastrium, nausea, pallor, flushing, lightheadedness Postictal: Normal consciousness

Generalized Seizures: Tonic-Clonic (grand mal)

Manifestations: Loses consciousness suddenly, and the body stiffens into tonic extensor rigidity; breathing stops, and the person becomes cyanotic; clonic phase of rhythmic muscular contraction follows; breathing resumes and is noisy with excessive salivation; injury, tongue biting, and urinary incontinence may occur Postictal state: Confusion, drowsiness, fatigues, HA, muscular aching, temporary persistence of neurologic deficits such as hyperactive reflexes and Babinski reflex; amnesia for the seizure

Pseudoseizures

Manifestations: May mimic seizures but are due to conversion reaction; movements may have personally symbolic significance and often do not follow neuroanatomic pattern, injury is uncommon Postictal state: Variable

Focal Seizures with Impairment of Consciousness

Manifestations: May or may not start with autonomic or psychic symptoms; consciousness is impaired, and the person appears confused; automatisms include automatic motor behaviors such as chewing, smacking lips, walking about, and unbuttoning clothes Postictal: Patient may remember initial autonomic or psychic symptoms (aura) but is amnesic for the rest of the seizure; confusion and headache may occur

Focal Seizures without Impairment of Consciousness or Awareness: Subjective sensory or psychic phenomena

Manifestations: Numbness, tingling, simple visual, auditory, or olfactory hallucinations such as flashing lights, buzzing or odors; anxiety or fear feelings of familiarity or unreality, dreamy states, fear or rage, flashbacks, hallucinations Postictal: Normal consciousness

Focal Seizures that Become Generalized

Manifestations: Partial seizures that become generalized resemble tonic-clonic seizures; patient may not recall focal onset Postictal: Two attributes indicate a partial seizure that has become generalized (1) recollection of aura, and (2) unilateral neurologic deficit during the postictal period

Generalized Seizures: Absence

Manifestations: Sudden brief lapse in consciousness, with blinking, staring, or movements of the lips and hands but no falling; typical absence (less than 10 seconds and stop abruptly) and atypical absence (more than 10 second) Postictal state: No aura; typical return to normal, atypical some confusion

Generalized Seizures: Myoclonic Atonic (drop attack)

Manifestations: Sudden loss of consciousness with falling but no movements, injury may occur Postictal state: Prompt return or brief confusion

Generalized Seizures: Myoclonic

Manifestations: Sudden, brief, rapid jerks involving the trunk or limbs Postictal state: Variable

Focal Seizures without Impairment of Consciousness or Awareness: Jacksonian

Manifestations: Tonic then clonic movements that start unilaterally in hand, foot, or face, and spread to other parts on same side Postictal: Normal consciousness

Focal Seizures without Impairment of Consciousness or Awareness: Other motor symptoms

Manifestations: Turning of the head and eyes to one side, or tonic and clonic movements of an arm or leg without Jacksonian spread Postictal: Normal consciousness

Vasopressor or Vasovagal Syncope

Mechanism: Common faint; sudden peripheral vasodilation without compensatory rise in cardiac output; heart rate then BP fall; slow onset and offset Precipitating factors: Strong emotion - fear or pain Predisposing factors: Fatigue, hunger, hot humid environment Prodromal: Restless, weakness, pallor, nausea, salivation, sweating, yawning Postural associations: Usually standing, possibly sitting Recovery: Prompt return of consciousness when lying down, but other symptoms may persist for a time

Disorders Resembling Syncope: Hypocapnia due to Hyperventilation

Mechanism: Constriction of cerebral blood vessels secondary to hypocapnia induced by hyperventilation Precipitating factors: Anxiety, panic disorder Predisposing factors: Anxiety Prodromal: Dyspnea, palpitations, chest discomfort, numbness and tingling; maintain consciousness Postural associations: Any position Recovery: Slow improvement as hyperventilation ceases

Syncope due to Arrhythmias

Mechanism: Decreased cardiac output from cardiac ischemia, ventricular arrythmias, prolonged QT, persistent bradycardia, infrafascicular block Precipitating factors: Sudden change in rhythm Predisposing factors: Heard disease, aging Prodromal: None Postural associations: Any position Recovery: Prompt return to normal, prolonged cerebral hypoperfusion, cardiac arrest

Orthostatic (Postural) Hypotension

Mechanism: Inadequate vasconstrictor reflexes or hypovolemia Precipitating factors: Standing up; possibly after hemorrhage or dehydration Predisposing factors: Central and peripheral neuropathies, diabetes, amyloidosis, antihypertensive vasodilator drugs, bed rest; bleeding, diuretics, vomiting, diarrhea, polyuria Prodromal: None; light-headedness and palpitations on standing Postural associations: Occurs soon after person stands Recovery: Return to normal when lying down; volume repletion

Disorders Resembling Syncope: Hypoglycemia

Mechanism: Insufficient glucose to maintain cerebral metabolism; secretion of epinephrine contributes to symptoms Precipitating factors: Variable, fasting Predisposing factors: Insulin therapy, metabolic disorders Prodromal: Sweating, tremor, palpitations, hunger, headache, confusion, abnormal behavior, coma Postural associations: Any position Recovery: Variable

Cough Syncope

Mechanism: Neurally mediated, possible vagal stimulation Precipitating factors: Severe paroxysm of coughing Predisposing factors: Chronic bronchitis in muscular man Prodromal: Cough Postural associations: Any position Recovery: Prompt return to normal

Syncope due to Myocardial Infarction

Mechanism: Sudden arrhythmia or decreased cardiac output Precipitating factors: Variable Predisposing factors: Coronary artery disease Prodromal: Ischemic chest pain Postural associations: Any position Recovery: Variable

Syncope due to Massive Pulmonary Embolism

Mechanism: Sudden hypoxia or decreased cardiac output Precipitating factors: Variable, including prolonged bed rest and clotting disorders Predisposing factors: DVT, bedrest, hypercoagulable states, protein S or C deficiency, antithrombin III deficiency, estrogen therapy Prodromal: Dyspnea, pleuritic chest pain Postural associations: Any position Recovery: Related to time to diagnose and treat

Disorders Resembling Syncope: Hysterical Fainting from Conversion Reaction

Mechanism: Symbolic expression of unacceptable idea through body language; skin color and vital signs may be normal; sometimes with bizarre and purposive movements; in the presence of other people Precipitating factors: Stressful situation Predisposing factors: Hysterical personality traits Prodromal: Variable Postural associations: Slump to the floor, often from standing without injury Recovery: Variable, fluctuating responsiveness

Syncope due to Aortic Stenosis and Hypertrophic Cardiomyopathy

Mechanism: Vascular resistance falls with exercise, but cardiac output cannot rise due to outflow obstruction Precipitating factors: Exercise Predisposing factors: Cardiac disorders Prodromal: None, sudden onset Postural associations: With or after exercise Recovery: Prompt return to normal

Micturition Syncope

Mechanism: Vasovagal stimulation Precipitating factors: Emptying of bladder after getting out of bed to void Predisposing factors: Nocturia, usually in elderly or adult men Prodromal: None Postural associations: Standing to void Recovery: Prompt return to normal

Resting (Static) Tremors

Most prominent at rest and may decrease or disappear with voluntary movement Example: Slow, fine, pill-rolling tremor of parkinsonism, about 5 per second

Level of Consciousness: Obtundation

Opens the eyes and looks at you but responds slowly and is somewhat confused; alertness and interest in the environment are decreased Technique: Shake patient gently

Facial Paralysis: CN VII (Right Sided) Peripheral Lesion

Paralyzes the entire right side of the face, including the forehead Closing eyes: Right eye does not close, eyeball rolls up Flat nasolabial fold Raising eyebrows: Right side of forehead not wrinkled, eyebrow not raise Paralysis of lower face

Toxic-Metabolic Coma

Patho: Arousal centers poisoned or critical substrates depleted Features: Respiratory pattern may be normal, hyperventilation, or Cheyne-Stokes; Pupils are equal and reactive to light, may be pinpoint from opiates or cholinergics, may be fixed and dilated from anticholinergics or hypothermia; LOC changes after pupils change Causes: Uremia, hyperglycemia, alcohol, drugs, liver failure, hypothyroidism, hypoglycemia, anoxia, ischemia, meningitis, encephalitis, hyperthermia, hypothermia

Structural Coma

Patho: Lesion destroys or compresses brainstem arousal areas, either directly or secondary to more distant expanding mass lesions Features: Respirations are irregular with Cheyne-Stokes or ataxic breathing, may have "apneustic" respiration (peak inspiratory arrest) or central hyperventilation; Pupils are unequal and unreactive to light (midposition and fixed suggests midbrain compression, dilated and fixed suggests compression of CN III from herniation); LOC changes before pupils change Causes: Hemorrhage, infarct or embolus, tumor, abscess

Wernicke's Aphasia

Quality of speech: Fluent; often rapid, voluble, and effortless; inflection and articulation are good, but sentences lack meaning and words are malformed (paraphasias) or invented (neologisms); speech may be totally incomprehensible Word comprehension: Impaired Repetition: Impaired Naming: Impaired Reading comprehension: Impaired Writing: Impaired Location of lesion: Posterior superior temporal lobe

Broca's Aphasia

Quality of speech: Nonfluent; slow, with few words and laborious effort; inflection and articulation are impaired but words are meaningful, with nouns, transitive verbs, and important adjectives; small grammatical words are often dropped Word comprehension: Fair to good Repetition: Impaired Naming: Impaired, though patient recognizes objects Reading comprehension: Fair to good Writing: Impaired Location of lesion: Posterior inferior frontal lobe

Generalized Seizures

Rapidly engaging, bilaterally distributed Location and lateralization are not consistent from one seizure to another Begin with body movements, impaired consciousness or both When tonic-clonic seizures begin after 30, suspect partial seizure that has become generalized or a general seizure caused by a toxic or metabolic disorder (withdrawal from alcohol or sedative drugs, uremia, hypoglycemia, hyperglycemia, hyponatremia, and bacterial meningitis)

Level of Consciousness: Comatose

Remains unarousable with eyes closed; no evident response to inner need or external stimuli Technique: Apply repeated painful stimuli

Febrile Convulsions

Resemble brief tonic-clonic seizures May occur in infants and young children Benign but may be first manifestation of seizure disorder

Nystagmus

Rhythmic oscillation of the eyes, analogous to a tremor in other parts of the body Cause: Impairment of vision in early life, disorders of the labrynth and the cerebellar system, and drug toxicity Occurs normally when a person watches a rapidly moving object

Tremors

Rhythmic oscillatory movements, which may be roughly subdivided into three groups: Resting (Static) Postural Intentional

Involuntary Movements: Oral-Facial Dyskinesias

Rhythmic, repetitive, bizarre movements that chiefly involve the face, mouth, jaw, and tongue: Grimacing, pursing of the lips, protrusions of the tongue, opening and closing of the mouth, and deviations of the jaw Limbs and trunk are less involved Cause: Late complication of psychotropic drugs in tardive dyskinesia; also in psychoses, elderly, and edentulous persons

Gait and Posture: Spastic Hemiparesis

Seen in corticospinal tract lesions in stroke Poor control of flexor muscles during swing phase Affected arm is flexed, immobile, and held close to side, with elbow, wrists, and interphalangeal joints flexed; affected leg extensors spastic; ankle plantar-flexed and inverted May drag toe, circle leg stiffly outward and forward, or lean trunk to contralateral side to clear affected leg

Gait and Posture: Cerebellar Ataxia

Seen in disease of cerebellum or associated tracts Gait is staggering, unsteady, and wide-based, with exaggerated difficulty on turns Patients cannot stand steadily with feet together, eyes open or close Other signs: Dysmetria, nystagmus, intention tremor

Gait and Posture: Steppage Gait

Seen in foot drop, usually secondary to peripheral motor unit disease Drag the feet or lift them high, with knees flexed, and bring them down with a slap on the floor (appear to be walking up stairs); tibialis anterior and toe extensors are weak Cannot walk on heels May involve one or both legs

Gait and Posture: Sensory Ataxia

Seen in loss of position sense in the legs (with polyneuropathy or posterior column damage) Gait is unsteady with wide base Patients throw their feet forward and outward and bring them down, first on heels and then on toes, with a double tapping sound; watch the ground for guidance Cannot stand steadily with feet together when eyes closed (positive Romberg sign), and staggering gait worsens

Gait and Posture: Scissors Gait

Seen in spinal cord disease, causing bilateral lower extremity spasticity, including adductor spasm, and abnormal propioception Gait is stiff; patients advance each leg slowly, and the thighs tend to cross forward on each other at each step; steps are short Patient appears to be walking through water Scissoring is seen in all spasticity disorders, most commonly cerebral palsy

Gait and Posture: Parkinsonian Gait

Seen in the basal-gangia defects of Parkinson's Posture is stooped, with flexion of head, arms, hips, and knees Patients are slow getting started; steps are short and shuffling, with involuntary hastening (festination) Arm swings are decreased, and patients turn around stiffly Postural control is poor (retropulsion)

Involuntary Movements: Dystonia

Similar to athetoid movements, but often involve larger portions of the body, including the trunk Grotesque, twisted postures may result Cause: Drugs, primary torsion dystonia, and spasmodic torticollis

Involuntary Movements: Athetosis

Slower and more twisting and writhing than choreiform movements, and have a larger amplitude Commonly involve face and extremities; associated with spasticity Cause: Cerebral palsy

Hemiplegia

Sudden unilateral brain damage involving the corticospinal tract Flaccid early in its course, spasticity will develop later Paralyzed arm and leg are slack (leg may externally rotate); one side of lower face may be paralyzed, cheek puffs out on expiration; eyes may be turned away from paralyzed side Spontaneous movement or responses to stimuli are limited to the opposite sitde

One Large Fixed and Dilated Pupil

Warns of herniation of the temporal lobe, causing compression of the oculomotor nerve and midbrain Commonly seen in diabetic patients with infarct of CN III