ABEM Neurological & Psychiatric Disorders 3 — Questions and Answers
Question 1: A 28-year-old presents with acute psychosis, severe agitation, hyperthermia, rigidity, and elevated CK after starting haloperidol 3 days ago. What is the most likely diagnosis?
- Malignant hyperthermia
- Neuroleptic malignant syndrome (Correct answer)
- Serotonin syndrome
- Anticholinergic toxicity
Correct answer: Neuroleptic malignant syndrome
Neuroleptic malignant syndrome (NMS) presents with hyperthermia, lead-pipe rigidity, altered mental status, and autonomic instability following antipsychotic use.
Question 2: Which feature best differentiates Todd's paralysis from an acute ischemic stroke in a patient with post-ictal focal weakness?
- Presence of headache
- Gradual resolution of weakness over minutes to hours (Correct answer)
- Elevated blood pressure
- Abnormal CT head
Correct answer: Gradual resolution of weakness over minutes to hours
Todd's paralysis (post-ictal paresis) typically resolves within minutes to hours after a seizure, whereas stroke deficits are persistent.
Question 3: A 35-year-old with HIV presents with headache, fever, and altered mental status. CSF shows lymphocytic pleocytosis and India ink staining is positive. What is the treatment?
- IV acyclovir
- Amphotericin B plus flucytosine (Correct answer)
- Trimethoprim-sulfamethoxazole
- Dexamethasone plus ceftriaxone
Correct answer: Amphotericin B plus flucytosine
Cryptococcal meningitis in HIV patients is treated with amphotericin B plus flucytosine for induction therapy.
Question 4: A 60-year-old woman presents with painless diplopia, ptosis, and a dilated pupil. She has a known posterior communicating artery aneurysm. What is the most urgent next step?
- Administer IV methylprednisolone
- Emergent neurosurgical or interventional neuroradiology consultation (Correct answer)
- MRI orbits with contrast
- Prescribe eye patch and outpatient follow-up
Correct answer: Emergent neurosurgical or interventional neuroradiology consultation
Third nerve palsy with pupil involvement from a PComm aneurysm represents a surgical emergency due to risk of rupture and subarachnoid hemorrhage.
Question 5: A patient presents with tetanus following a puncture wound. Which medication directly addresses the pathophysiology of muscle spasms in tetanus?
- Tetanus immune globulin (TIG)
- Metronidazole
- Benzodiazepines (Correct answer)
- Penicillin G
Correct answer: Benzodiazepines
Tetanus toxin blocks inhibitory neurotransmitter release (glycine and GABA), causing muscle spasms best managed with benzodiazepines that enhance GABA activity.
Question 6: A 40-year-old presents with sudden unilateral vision loss, described as a 'shade coming down' over the eye that resolved in 10 minutes. What is this phenomenon called and what does it indicate?
- Amaurosis fugax — indicates carotid artery disease (Correct answer)
- Ocular migraine — indicates cortical spreading depression
- Retinal detachment — requires immediate ophthalmology referral
- Central retinal artery occlusion — requires tPA
Correct answer: Amaurosis fugax — indicates carotid artery disease
Amaurosis fugax (transient monocular blindness) is caused by emboli from ipsilateral carotid stenosis temporarily occluding retinal blood flow.
Question 7: An 18-year-old male presents with his third episode of sudden bilateral leg weakness with preserved consciousness, triggered by emotional laughter. EEG is normal during an episode. What is the most likely diagnosis?
- Absence seizure disorder
- Cataplexy associated with narcolepsy (Correct answer)
- Conversion disorder
- Transient ischemic attack
Correct answer: Cataplexy associated with narcolepsy
Cataplexy is characterized by sudden bilateral muscle weakness triggered by strong emotions (especially laughter), associated with narcolepsy, with preserved consciousness and normal EEG.
ABEM Neurological & Psychiatric Disorders 3
A 28-year-old presents with acute psychosis, severe agitation, hyperthermia, rigidity, and elevated CK after starting haloperidol 3 days ago.
What is the most likely diagnosis?