PLAB Clinical Medicine & Diagnosis — Questions and Answers
Question 1: A 55-year-old male presents with crushing central chest pain radiating to the left arm and jaw. What is the most likely diagnosis?
- Acute myocardial infarction (Correct answer)
- Gastroesophageal reflux disease
- Pulmonary embolism
- Musculoskeletal chest pain
Correct answer: Acute myocardial infarction
Crushing central chest pain radiating to the left arm and jaw in a middle-aged male is a classic presentation of acute myocardial infarction requiring immediate assessment and treatment.
Question 2: Which investigation is the gold standard for diagnosing pulmonary embolism?
- CT pulmonary angiography (CTPA) (Correct answer)
- Chest X-ray
- D-dimer blood test
- Electrocardiogram
Correct answer: CT pulmonary angiography (CTPA)
CT pulmonary angiography is the gold standard investigation for diagnosing pulmonary embolism, providing direct visualization of clots in the pulmonary arterial system.
Question 3: A patient presents with polyuria, polydipsia, and unexplained weight loss. Which condition should be investigated first?
- Diabetes mellitus (Correct answer)
- Urinary tract infection
- Chronic kidney disease
- Hyperthyroidism
Correct answer: Diabetes mellitus
The classic triad of polyuria (frequent urination), polydipsia (excessive thirst), and unexplained weight loss strongly suggests diabetes mellitus, requiring blood glucose testing.
Question 4: What is the first-line treatment for community-acquired pneumonia in an otherwise healthy adult in the United States?
- Amoxicillin or azithromycin (Correct answer)
- Intravenous vancomycin
- Oral metronidazole
- Topical gentamicin
Correct answer: Amoxicillin or azithromycin
For community-acquired pneumonia in healthy adults without comorbidities, amoxicillin or azithromycin (for penicillin-allergic patients) is recommended as first-line outpatient therapy.
Question 5: A patient presents with sudden onset severe headache described as 'the worst headache of my life.' What is the most important diagnosis to exclude?
- Subarachnoid hemorrhage (Correct answer)
- Tension headache
- Migraine with aura
- Cluster headache
Correct answer: Subarachnoid hemorrhage
A sudden-onset severe 'thunderclap' headache described as the worst ever experienced requires urgent exclusion of subarachnoid hemorrhage, a potentially life-threatening condition.
Question 6: What is the most appropriate initial investigation for suspected deep vein thrombosis?
- D-dimer test combined with Wells score assessment (Correct answer)
- Full blood count only
- Chest X-ray
- Liver function tests
Correct answer: D-dimer test combined with Wells score assessment
Initial investigation of suspected DVT involves calculating the Wells score to determine pre-test probability, combined with a D-dimer test. A positive D-dimer in a moderate/high probability patient warrants ultrasound.
PLAB Clinical Medicine & Diagnosis
A 55-year-old male presents with crushing central chest pain radiating to the left arm and jaw.
What is the most likely diagnosis?