USMLE and Neuroanatomy 3/16/14 Flashcards
What are characteristics of normal aging?
Occasional forgetfulness, difficulty word finding, difficulty falling asleep, low energy
Type of aphasia: word-finding difficulty
Expressive / non-fluent aphasia
In age-related expressive/non-fluent aphasia, what is the etiology?
Impairment of dominant frontal lobe function, age-related
Diagnosis of dementia requires:
impairment in daily functioning
Anterior circulation of the brain includes what vessels?
ICA and its branches (ACA, MCA)
Posterior circulation of the brain includes what vessels?
Paired vertebral arteries —> basilar artery —> paired PCAs
ACA stroke: characteristic features
Contralateral motor/sensory deficits leg>arm, urinary incontinence, gait apraxia, primitive reflexes, abulia, paratonic rigidity
Pronator Drift
sensitive test for UMN disease that pt may not otherwise notice; weakness in supination results in dominant pronation (pt with eyes closed)
Wernicke’s Encephalopathy: diagnostic triad
encephalopathy, oculomotor dysfunction, gait ataxia
Subarachnoid hemorrhage: clinical features
Worst headache of life; due to ruptured berry aneurysm; meningeal irritation (neck stiffness), uncommon focal deficits
Subarachnoid hemorrhage: complications
Rebleed (first 24h), vasospasm (after 3d), increased ICP; seizures; hyponatremia (from SIADH)
Subarachnoid hemorrhage: diagnosis
Noncontrast CT; LP; xanthochromia in CSF (usually 6h after onset), CTA-A to identify source
Subarachnoid hemorrhage: treatment
Coiling and/or stenting; nimodipine & hyperdynamic tx to reduce vasospasm
Myasthenia Crisis: definition
Life-threatening condition characterized by weakness of respiratory and pharyngeal muscles
Myasthenia Crisis: treatment
Endotracheal intubation, w/d of AChEis for a few days; treat concomitant infection; monitor PFTs
Treatment of acute exacerbations of MS
Corticosteroids (IV)
GBM: CT/MRI characteristic findings
butterfly appearance w/central necrosis
High-grade astrocytoma: CT/MRI characteristic findings
Heterogenous, serpiginous contrast enhancement
GBS: predisposing conditions
campylobacter infection, vaccination
Craniopharyngioma
benign tumors arising from Rathke’s pouch; bimodal age distribution (kids and 55-65yo); cysts filled w/oily material; located above sella turcica
Craniopharyngioma: clinical feature
bitemporal hemianopia (compression of optic chiasm)
Cauda Equina Syndrome: features
bilateral severe radicular pain; saddle anesthesia; asymmetric motor weakness; hyporeflexia/areflexia; late-onset bowel & bladder dysfunction
Conus Medullaris Syndrome: features
sudden onset severe back pain; perianal hypo/anesthesia; symmetric motor weakness; early-onset bowel and bladder dysfunction
CES v. CMS: LMN or UMN signs?
CES: LMN
CMS: UMN + LMN
Conus Medullaris nerve roots
S1-S5
Treatment for CES?
Emergent MRI, neurosurgical intervention, IV glucocorticoids
Cavernous Sinus: contents
ICA, CN III, IV, V, VI
Cavernous Sinus Thrombosis: pathophys
facial/ophthalmic venous system is valveless
Cavernous Sinus Thrombosis: clinical features
headahce, binocular palsies, periorbital edema, hypoesthesia/hyperesthesia
Cavernous Sinus Thrombosis: treatment
antibiotics, prevent herniation
Cavernous Sinus Thrombosis: red flags
headache, bilateral periorbital edema, CN III, IV, V, VI deficits
CNs that exit in the midbrain:
III, IV
CNs that exit in the pons:
V, VI, VII, VIII
CNs that exit in the medulla:
IX, X, XII
CNs that exit medially:
MOTOR- III, IV, VI, XII
CNs that exit laterally:
MIXED- V, VII, IX, X
Most cranial nerves exit ventrally or dorsally?
Ventral/ventralateral
Which CN exits dorsally?
IV, just posterior or below the inferior colliculi
Superior Cerebellar Peduncle
Efferent route from cerebellum; projections from deep cerebellar nuclei —> red nucleus and thalamus (VL)
Middle Cerebellar Peduncle
Largest CP, contains fibers from contralateral pontine nuclei —> mossy fibers in cerebellar cortex
Inferior Cerebellar Peduncle
Input route to cerebellum, contains:
- Crossed olivocerebellar fibers
- Uncrossed posterior spinocerebellar and cuneocerebellar fibers, vestibulocerebellar fibers, and other cerebellar afferents
Spinocerebellar tract
Clarke’s Nucleus (T1-L2) —> info about biomechanics state of muscle spindles and GTOs in Lower Extremity
Cuneocerebellar tract
External cuneate nucleus (medulla) —> info about biomechanics state of muscle spindles and GTOs in upper extremity
Corticospinal tract
precentral gyrus (motor cortex) —> post limb of internal capsule —> cross in pyramidal decussation (medulla) —> lateral corticospinal tract —> synapse in anterior horn of spinal cord
Anterolateral (Spinothalamic) System
Pain, temp, crude touch; afferents cross 1-2 levels ABOVE their dorsal roots
Anterolateral (Spinothalamic) System: path
Dorsal root ganglion —> cross 1-2 spinal levels above —> anterolateral pathway —> synapse in thalamus (VPL nucleus) —> primary somatosensory cortex
Dorsolateral / Medial Lemniscus System
vibration, proprioception, light touch
Dorsolateral / Medial Lemniscus System: path
Dorsal root ganglion —> dorsal columns —> gracilis/cuneate nucleus in medulla —> sensory decussation —> medial lemniscus —> synapse in thalamus (VPL) —> primary somatosensory cortex
