ABIM Neurology — Questions and Answers
Question 1: For an eligible patient with acute ischemic stroke, what is the standard time window from last known well for IV thrombolysis (alteplase or tenecteplase)?
- 1 hour
- 24 hours
- 4.5 hours (Correct answer)
- 12 hours
Correct answer: 4.5 hours
IV thrombolysis is indicated within 4.5 hours of last known well in eligible patients. Mechanical thrombectomy for large-vessel occlusion can extend to 24 hours in selected patients.
Question 2: A patient has acute right facial weakness that includes the forehead, with no other deficits, and presents within 48 hours. What is the most appropriate treatment?
- Emergent thrombolysis
- Oral prednisone (Correct answer)
- IV acyclovir alone
- Observation only; steroids are contraindicated
Correct answer: Oral prednisone
Weakness that involves the forehead indicates a peripheral (lower motor neuron) lesion consistent with Bell palsy. Corticosteroids started within 72 hours improve recovery. Antivirals alone are not effective, and a central lesion such as stroke typically spares the forehead.
Question 3: A 35-year-old woman has ptosis and diplopia that worsen through the day, along with fatigable proximal weakness. Which test is most specific for the likely diagnosis?
- Serum CK
- Anti-GQ1b antibody
- MRI brain
- Acetylcholine receptor antibodies (Correct answer)
Correct answer: Acetylcholine receptor antibodies
Fatigable ocular and limb weakness suggests myasthenia gravis. Acetylcholine receptor antibodies are positive in about 85% of generalized cases and are highly specific.
Question 4: A patient has ascending symmetric leg weakness and absent reflexes 2 weeks after a diarrheal illness. Which CSF finding supports the diagnosis?
- Elevated protein with a normal cell count (Correct answer)
- Elevated WBC with low glucose
- Oligoclonal bands with lymphocytosis
- Xanthochromia
Correct answer: Elevated protein with a normal cell count
Guillain-Barré syndrome classically shows albuminocytologic dissociation: high CSF protein with a normal white cell count. Serial vital capacity (FVC) monitoring is essential because of the risk of respiratory failure.
Question 5: A patient has a generalized convulsive seizure lasting 7 minutes and has IV access. What is the first-line treatment?
- IV phenytoin
- IV levetiracetam
- IV lorazepam (Correct answer)
- Propofol infusion
Correct answer: IV lorazepam
A benzodiazepine is first-line for status epilepticus, with IV lorazepam preferred when IV access exists. Levetiracetam, fosphenytoin, or valproate are second-line if seizures continue. Anesthetic infusions are for refractory status.
Question 6: Which clinical feature is required to diagnose Parkinson disease under MDS criteria?
- Resting tremor
- Bradykinesia (Correct answer)
- Postural instability
- Dementia
Correct answer: Bradykinesia
MDS criteria define parkinsonism as bradykinesia plus resting tremor and/or rigidity, so bradykinesia is mandatory. Resting tremor is common but not required. Early dementia argues for dementia with Lewy bodies instead.
