OSCE Clinical Reasoning 3 — Questions and Answers
Question 1: A 45-year-old woman presents with sudden onset headache she describes as 'the worst headache of my life.' She is neurologically intact. What diagnosis must be ruled out first?
- Migraine
- Subarachnoid hemorrhage (Correct answer)
- Hypertensive urgency
- Cluster headache
Correct answer: Subarachnoid hemorrhage
A thunderclap headache described as the worst of one's life is subarachnoid hemorrhage until proven otherwise, requiring urgent CT head and LP if CT is negative.
Question 2: Which approach best illustrates illness script-based reasoning in clinical medicine?
- Listing all possible diagnoses alphabetically
- Matching a patient's presentation to a stored pattern of disease features, risk factors, and outcomes (Correct answer)
- Ordering a comprehensive metabolic panel for every patient
- Using a checklist to exclude diagnoses sequentially
Correct answer: Matching a patient's presentation to a stored pattern of disease features, risk factors, and outcomes
Illness scripts are mental frameworks linking epidemiology, pathophysiology, and clinical features to a specific diagnosis for rapid pattern recognition.
Question 3: A 30-year-old male presents after a seizure with no prior history. He is post-ictal but vitals are stable. What is the most important initial investigation?
- EEG
- MRI brain
- Blood glucose (Correct answer)
- Lumbar puncture
Correct answer: Blood glucose
Hypoglycemia is a rapidly reversible and immediately life-threatening cause of seizure that must be excluded first with a bedside glucose check.
Question 4: A diabetic patient presents with a painless foot ulcer. The ulcer has a punched-out appearance with surrounding callus. Foot pulses are intact. What type of ulcer is this?
- Venous ulcer
- Arterial ulcer
- Neuropathic ulcer (Correct answer)
- Pressure ulcer
Correct answer: Neuropathic ulcer
Painless, punched-out ulcers with surrounding callus at pressure points with intact pulses are characteristic of diabetic neuropathic ulcers.
Question 5: When using the hypothetico-deductive reasoning model, what does the clinician do after generating initial hypotheses?
- Orders all available tests
- Gathers targeted data to confirm or refute each hypothesis (Correct answer)
- Selects the most common diagnosis as the working diagnosis
- Documents the differential and waits for specialist review
Correct answer: Gathers targeted data to confirm or refute each hypothesis
The hypothetico-deductive model involves iteratively gathering targeted history, exam, and test data to confirm or eliminate each hypothesis.
Question 6: A febrile 3-year-old is brought in with a bulging fontanelle, neck stiffness, and a petechial rash. What is the immediate priority action?
- Lumbar puncture
- Blood cultures and immediate IV antibiotics (Correct answer)
- CT head
- Corticosteroids
Correct answer: Blood cultures and immediate IV antibiotics
Suspected bacterial meningitis with hemodynamic compromise requires immediate IV antibiotics; do not delay treatment for imaging or LP.
Question 7: A patient with a history of atrial fibrillation on warfarin presents with sudden left-sided weakness and facial droop lasting 2 hours that fully resolved. What is the most likely diagnosis?
- Completed ischemic stroke
- Transient ischemic attack (TIA) (Correct answer)
- Todd's palsy
- Hemiplegic migraine
Correct answer: Transient ischemic attack (TIA)
Focal neurological deficits that completely resolve within 24 hours (classically <1 hour) in a patient with cardioembolic risk factors represent a TIA.
OSCE Clinical Reasoning 3
A 45-year-old woman presents with sudden onset headache she describes as 'the worst headache of my life.' She is neurologically intact.
What diagnosis must be ruled out first?