Neurology- Neurophatology Flashcards
Common brain lesions
- Frontal lobe
- Frontal eye fields
Disinhibition and deficits in concentration, orientation, judgment; primitive reflexes.
Eyes look toward (destructive) side of lesion. In seizures (irritative), eyes look away from side of the lesion.
Common brain lesions
- Paramedian pontine reticular formation
- Medial longitudinal fasciculus
Ipsilateral gaze palsy (inability to look toward side of lesion).
Internuclear ophthalmoplegia (impaired adduction of ipsilateral eye; nystagmus of contralateral eye with abduction).
Common brain lesions
- Dominant parietal cortex
- Nondominant parietal cortex
Agraphia, acalculia, finger agnosia, left-right disorientation (Gestmann Sx).
Agnosia of the contralateral side of the world. (Hemispatial neglect syndrome)
Common brain lesions
- Hippocampus (bilateral)
- Basal ganglia
- Subthalamic nucleus
Anterograde amnesia
May result in tremor at rest, chorea, athetosis.
Contralateral hemiballismus
Common brain lesions
- Mammillary bodies (bilateral)
Wernicke-Korsakoff syndrome—Confusion, Ataxia, Nystagmus, Ophthalmoplegia, memory loss, confabulation, personality changes.
Common brain lesions
- Amygdala (bilateral)
- Dorsal midbrain
Klüver-Bucy syndrome—disinhibited behavior (HSV-1 encephalitis)
Parinaud syndrome—vertical gaze palsy, pupillary light-near dissociation, lid retraction, convergence-retraction nystagmus. (Stroke, hydrocephalus, pinealoma)
Common brain lesions
- Reticular activating system (midbrain)
- Cerebellar hemisphere
- Cerebellar Vermis
Reduced levels of arousal and wakefulness (eg, coma).
Intention tremor, limb ataxia, loss of balance; ipsilateral deficits; fall toward side of lesion.
Truncal ataxia (wide-based, “drunken sailor” gait), dysarthria.
Common brain lesions
- Decorticate (flexor) posturing
- Decerebrate (extensor) posturing
lesion above red nucleus, presents with flexion of upper extremities and extension of lower extremities.
Lesion at or below red nucleus, presents with extension of upper and lower extremities.
Ischemic brain disease/stroke
- Most vulnerable areas
- Stroke imaging
hippocampus, neocortex, cerebellum (Purkinje cells), watershed areas.
Noncontrast CT to exclude hemorrhage (before tPA can be given). CT detects ischemic changes in 6–24 hr. Diffusion-weighted MRI can detect ischemia within 3–30 min.
Ischemic stroke
- Types
- Treatment
Thrombotic, embolic, hypoxic
tPA (if within 3–4.5 hr). Medical therapy (eg, aspirin, clopidogrel); optimum control of blood pressure, blood sugars, lipids; and treat conditions that risk (eg, atrial fibrillation, carotid artery stenosis).
Neonatal intraventricular hemorrhage
Bleeding into ventricles. Increased risk in premature and low-birth-weight infants. Originates in germinal matrix, a highly vascularized layer within the subventricular zone.
Due to reduced glial fiber support and impaired autoregulation of BP in premature infants. Can present with altered level of consciousness, bulging fontanelle, hypotension, seizures, coma.
Intracranial hemorrhage
- Epidural
Rupture of middle meningeal artery (pterion).
Scalp hematoma and rapid intracranial expansion under systemic arterial pressure transtentorial
herniation, CN III palsy.
CT shows biconvex (lentiform), hyperdense blood collection
Intracranial hemorrhage
- Subdural
Rupture of bridging veins. Seen in shaken babies. Predisposing: brain atrophy, Trauma.
Crescent-shaped hemorrhage that crosses suture lines. Can cause midline shift, findings of “acute on chronic” hemorrhage.
Intracranial hemorrhage
- Subarachnoid hemorrhage
Bleeding due to trauma, or rupture of an aneurysm, or arteriovenous malformation. Patients complain of “worst headache of my life.”
Xanthochromic spinal tap. Vasospasm can occur due to
blood breakdown or rebleed 3–10 days after hemorrhage ischemic infarct; nimodipine used to prevent/reduce vasospasm.
Intracranial hemorrhage
- Intraparenchymal hemorrhage
by systemic hypertension. Also seen with amyloid
angiopathy. vasculitis, neoplasm. May be 2º to reperfusion injury in ischemic stroke.
Hypertensive hemorrhages (Charcot- Bouchard microaneurysm) most often occur in putamen of basal ganglia (lenticulostriate vessels), followed by thalamus, pons, and cerebellum.
Effects of strokes
Pag. 498, 499
Diffuse axonal injury
Caused by traumatic shearing forces during rapid acceleration and/or deceleration of the brain.
devastating neurologic injury, often causing coma or
persistent vegetative state
Lateral medullary (Wallenberg) syndrome
Nucleus ambiguus effects are specific to PICA lesions.
“Don’t pick a (PICA) horse (hoarseness) that can’t eat
(dysphagia).”
Also supplies inferior cerebellar peduncle (part of cerebellum).
Lateral pontine syndrome
Facial nucleus effects are specific to AICA lesions.
“Facial droop means AICA’s pooped.”
Also supplies middle and inferior cerebellar peduncles (part of cerebellum).
aphasias
higher-order language deficit (inability to understand/produce/use language appropriately)
Pag. 500
Saccular aneurysm (berry)
Occurs at bifurcations in the circle of Willis. Most common site is junction of ACom and ACA. Associated with ADPKD, Ehlers-Danlos syndrome.
Usually clinically silent until rupture subarachnoid hemorrhage focal neurologic deficits
Saccular aneurysm (berry)
- ACom
- MCA
- PCom
Bitemporal hemianopia; ischemia in ACA distribution contralateral lower extremity hemiparesis, sensory deficits.
Ischemia in MCA distribution contralateral upper extremity and lower facial hemiparesis, sensory deficits.
Ipsilateral CN III palsy mydriasis (“blown pupil”); may also see ptosis, “down and out” eye
Partial (focal) seizures
- Types
Simple partial (consciousness intact)—motor, sensory, autonomic, psychic
Complex partial (impaired consciousness,
automatisms)
Generalized seizures
- Types
Absence (petit mal)—3 Hz spike-and-wave discharges, no postictal confusion, blank stare
Myoclonic—quick, repetitive jerks
Tonic-clonic (grand mal)—alternating stiffening and movement
Tonic—stiffening
Atonic—“drop” seizures (falls to floor); commonly mistaken for fainting
Epilepsy
Status epilepticus
disorder of recurrent seizures (febrile seizures are not epilepsy).
Continuous (≥ 5 min) or recurring seizures that may result in brain injury.
Cluster Headaches
- Localization and Duration
- Description
- Treatment
Unilateral. 15 min–3 hr; repetitive
Excruciating periorbital pain (“suicide headache”) with
lacrimation and rhinorrhea. May present with Horner
syndrome. More common in males.
Acute: sumatriptan, 100% O2
Prophylaxis: verapamil
Tension Headaches
- Localization and Duration
- Description
- Treatment
Bilateral. > 30 min (typically 4–6 hr); constant
Steady, “band-like” pain. No photophobia or phonophobia. No aura.
Analgesics, NSAIDs, acetaminophen; amitriptyline for chronic pain
Migraine Headaches
- Localization and Duration
- Description
- Treatment
Unilateral. 4–72 hr
POUND–Pulsatile, One-day duration, Unilateral, Nausea,Disabling
Acute: NSAIDs, triptans, dihydroergotamine
Prophylaxis: lifestyle changes, β-blockers, amitriptyline,
topiramate, valproate.
Movement disorders
Pag. 503
Parkinson
- Clinical manifestations
Parkinson TRAPS your body: Tremor (pill-rolling tremor at rest) Rigidity (cogwheel) Akinesia (or bradykinesia) Postural instability Shuffling gait
Parkinson
- Etiology
MPTP, a contaminant in illegal drugs, is metabolized to MPP+, which is toxic to substantia nigra.
Loss of dopaminergic neurons of substantia nigra pars
compacta.
Lewy bodies: composed of α-synuclein.
Huntington disease
- Etiology
- Clinical presentation
Caudate loses ACh and GABA. (CAG) repeat expansion in the huntingtin (HTT) gene on chromosome 4 (4 letters). AD
Between ages 20 and 50: chorea, athetosis, aggression, depression, dementia
Alzheimer disease
- Proteins associated
APP is located on chromosome 21. Most common cause of dementia.
Associated with the following altered proteins:
ApoE-2: risk of sporadic form
ApoE-4: risk of sporadic form
APP, presenilin-1, presenilin-2: familial forms (10%) with earlier onset
Alzheimer disease
- Histology and gross findings
Senile plaques in gray matter: extracellular β-amyloid core; may cause amyloid angiopathy intracranial hemorrhage; Aβ (amyloid-β) synthesized by cleaving amyloid precursor protein (APP).
Neurofibrillary tangles: intracellular, hyperphosphorylated tau protein; number of tangles
correlates with degree of dementia
Frontotemporal dementia (Pick disease)
- Clinical presentation
- Etiology
Early changes in personality and behavior (behavioral variant), or aphasia (primary progressive aphasia). May have associated movement disorders
Inclusions of hyperphosphorylated tau (round Pick bodies) or ubiquitinated TDP-43.
Lewy body dementia
- Clinical presentation
Visual hallucinations, dementia with fluctuating cognition/ alertness, REM sleep behavior disorder, and
parkinsonism.
Called Lewy body dementia if cognitive and motor symptom onset < 1 year apart, otherwise considered dementia 2° to Parkinson disease.
Vascular dementia
- Epidemiology
- Etiology
2nd most common cause of dementia
Result of multiple arterial infarcts and/or chronic ischemia.
Creutzfeldt-Jakob disease
- Clinical presentation
- EEG and CSF marker
- Etiology
Rapidly progressive dementia with myoclonus and ataxia.
Commonly see periodic sharp waves on EEG and 14-3-3 protein in CSF.
Spongiform cortex. Prions (PrPc PrPsc sheet [β-pleated sheet resistant to proteases])
Idiopathic intracranial hypertension (pseudotumor cerebri)
- Risk factors
- Clinical findings
- Treatment
Risk factors include female gender, Tetracyclines, Obesity, vitamin A excess, Danazol (female TOAD).
Findings: headache, tinnitus, diplopia, no change in mental status. Papilledema. Lumbar puncture reveals increase opening pressure
Treatment: weight loss, acetazolamide, invasive procedures for refractory cases.
Normal pressure hydrocephalus
Affects the elderly; idiopathic
Expansion of ventricles distorts the fibers of the corona radiata Triad of urinary incontinence, gait apraxia (magnetic gait), and cognitive dysfunction.
Ex vacuo ventriculomegaly
Appearance of increase CSF on imaging, but is actually due to decrease brain tissue and neuronal atrophy. ICP is normal; NPH triad is not seen.
Multiple sclerosis
- Presentation
Acute optic neuritis (Marcus Gunn pupil)
Brain stem/cerebellar syndromes
Pyramidal tract weakness
Spinal cord syndromes (Lhermitte phenomenon, neurogenic bladder, paraparesis, sensory)
Multiple sclerosis
- Findings
Increase IgG level and myelin basic protein in CSF.
Oligoclonal bands are diagnostic.
MRI is gold standard. Periventricular plaques. Multiple
white matter lesions disseminated in space and time.
Osmotic demyelination syndrome (central pontine myelinolisis)
- Etiology
- Clinical presentation
Massive axonal demyelination in pontine white matter 2° to rapid osmotic changeS.
Acute paralysis, dysarthria, dysphagia, diplopia, loss of
consciousness. Can cause “locked-in syndrome.”
Acute inflammatory demyelinating polyradiculopathy
- Phatophysiology
- Clinical presentation
Guillain-Barré syndrome. Autoimmune condition associated with infections that destroys Schwann cells.
Symmetric ascending muscle weakness/paralysis and depressed/absent DTRs. Facial paralysis and respiratory failure. May see autonomic dysregulation or sensory abnormalities.
*Increase CSF protein with normal cell count
Acute disseminated (postinfectious) encephalomyelitis
- Phatophysiology
- Clinical presentation
Multifocal inflammation and demyelination after infection or vaccination.
Presents with rapidly progressive multifocal neurologic symptoms, altered mental status.
Charcot-Marie-Tooth disease (hereditary motor and sensory neuropathy)
- Phatophysiology
- Clinical presentation
Defective production of proteins involved in the structure and function of peripheral nerves. Most common type, CMT1A, is caused by PMP22 gene duplication. AD
Associated with foot deformities, lower extremity weakness and sensory deficits.
Progressive multifocal leukoencephalopathy
- Phatophysiology
- Clinical presentation
Demyelination of CNS due to destruction of oligodendrocytes (2° to reactivation of latent
JC virus infection).
Seen in 2–4% of patients with AIDS. Risk
associated with natalizumab, rituximab.
Other demyelinating and dysmyelinating disorders
Krabbe disease, metachromatic leukodystrophy, adrenoleukodystrophy
