ABEM Neurological & Psychiatric Disorders 5 — Questions and Answers
Question 1: A 45-year-old presents with sudden facial drooping involving the forehead, inability to close the eye, and loss of taste on the anterior two-thirds of the tongue. What is the most likely diagnosis?
- Central (cortical) stroke affecting CN VII
- Bell's palsy (idiopathic peripheral CN VII palsy) (Correct answer)
- Ramsay Hunt syndrome
- Acoustic neuroma
Correct answer: Bell's palsy (idiopathic peripheral CN VII palsy)
Peripheral CN VII palsy (Bell's palsy) involves upper and lower face including forehead, distinguishing it from central lesions which spare the forehead due to bilateral cortical representation.
Question 2: A 19-year-old presents with sudden-onset psychosis, orofacial dyskinesias, autonomic instability, and decreased consciousness following a viral illness. Which antibody is most likely responsible?
- Anti-Hu antibody
- Anti-NMDA receptor antibody (Correct answer)
- Anti-voltage-gated calcium channel antibody
- Anti-MOG antibody
Correct answer: Anti-NMDA receptor antibody
Anti-NMDA receptor encephalitis presents with psychiatric symptoms, movement disorders, autonomic dysfunction, and decreased consciousness, often following herpes encephalitis or in young women with ovarian teratoma.
Question 3: A patient presents with locked-in syndrome after a pontine stroke. Which finding would you expect on examination?
- Absence of all brainstem reflexes
- Preserved vertical gaze and blinking with quadriplegia (Correct answer)
- Decerebrate posturing with intact consciousness
- Bilateral miosis and pinpoint pupils only
Correct answer: Preserved vertical gaze and blinking with quadriplegia
Locked-in syndrome from ventral pontine lesions spares the midbrain, preserving vertical eye movements and blinking (controlled by CN III/IV and superior colliculus) while causing quadriplegia.
Question 4: Which feature most reliably distinguishes hypertensive encephalopathy from hypertensive urgency without end-organ damage?
- Blood pressure level above 220/120 mmHg
- Presence of papilledema, encephalopathy, or focal neurological deficits (Correct answer)
- Presence of severe headache
- Elevated serum creatinine
Correct answer: Presence of papilledema, encephalopathy, or focal neurological deficits
Hypertensive emergency is defined by end-organ damage (encephalopathy, papilledema, focal deficits, AKI, heart failure) rather than a specific blood pressure threshold.
Question 5: A 70-year-old presents with sudden loss of pain and temperature sensation over his right arm and leg, with left-sided face numbness, and left-sided Horner syndrome. Which vessel is most likely occluded?
- Right middle cerebral artery
- Right anterior cerebral artery
- Left posterior inferior cerebellar artery (Correct answer)
- Left anterior inferior cerebellar artery
Correct answer: Left posterior inferior cerebellar artery
Left PICA occlusion causes lateral medullary (Wallenberg) syndrome with left-sided Horner and facial sensory loss, and crossed (right-sided) body pain/temperature loss via spinothalamic tract.
Question 6: A patient presents after a tonic-clonic seizure. Which finding on history or exam would most urgently warrant a CT head before lumbar puncture?
- Known seizure disorder with breakthrough seizure
- New focal neurological deficit with GCS 12 (Correct answer)
- Post-ictal drowsiness resolving over 20 minutes
- Single provoked seizure after alcohol binge
Correct answer: New focal neurological deficit with GCS 12
New focal neurological deficits after seizure may indicate an intracranial mass or hemorrhage; CT must precede LP to rule out herniation risk.
Question 7: A 38-year-old female presents with episodic severe unilateral headache with nausea, photophobia, and a preceding visual aura of a scintillating scotoma. Which medication is most appropriate for acute treatment of a moderate-to-severe attack?
- Acetaminophen 1000 mg PO
- Sumatriptan 6 mg SC (Correct answer)
- Metoprolol 50 mg PO
- Verapamil 80 mg PO
Correct answer: Sumatriptan 6 mg SC
Triptans (serotonin 5-HT1B/1D agonists) are first-line for moderate-to-severe migraine attacks; sumatriptan SC has the fastest onset.
ABEM Neurological & Psychiatric Disorders 5
A 45-year-old presents with sudden facial drooping involving the forehead, inability to close the eye, and loss of taste on the anterior two-thirds of the tongue.
What is the most likely diagnosis?