Physician Assistant Formulating a Diagnosis 2 — Questions and Answers
Question 1: A 55-year-old man presents with exertional chest pain radiating to the left arm, diaphoresis, and nausea. Which diagnosis should be highest on the differential?
- Acute myocardial infarction (Correct answer)
- Gastroesophageal reflux disease
- Costochondritis
- Panic disorder
Correct answer: Acute myocardial infarction
Classic symptoms of exertional chest pain with radiation to the left arm, diaphoresis, and nausea point strongly to acute myocardial infarction as the primary diagnosis.
Question 2: A PA uses Bayesian reasoning when formulating a diagnosis. Which factor most directly influences the post-test probability of a disease?
- Pre-test probability combined with test sensitivity and specificity (Correct answer)
- The patient's age alone
- The number of symptoms reported
- Insurance coverage of the diagnostic test
Correct answer: Pre-test probability combined with test sensitivity and specificity
Bayesian reasoning integrates pre-test probability with the likelihood ratios derived from test sensitivity and specificity to determine post-test probability.
Question 3: Which cognitive error occurs when a PA stops searching for additional diagnoses after identifying one that explains most of the patient's symptoms?
- Premature closure (Correct answer)
- Anchoring bias
- Framing effect
- Availability heuristic
Correct answer: Premature closure
Premature closure is the tendency to stop considering alternative diagnoses once an apparently satisfactory explanation is found, risking missed comorbidities.
Question 4: A 28-year-old woman presents with pleuritic chest pain, hemoptysis, and recent long-haul flight. Which diagnosis should be immediately considered?
- Pulmonary embolism (Correct answer)
- Community-acquired pneumonia
- Spontaneous pneumothorax
- Pericarditis
Correct answer: Pulmonary embolism
Pleuritic chest pain, hemoptysis, and recent immobilization from a long-haul flight constitute classic risk factors and symptoms for pulmonary embolism.
Question 5: When building a problem representation, which element best distinguishes it from a simple symptom list?
- A concise synthesis that highlights key epidemiological, temporal, and clinical features (Correct answer)
- A chronological list of every symptom the patient reports
- A verbatim transcript of the patient's chief complaint
- A list of all abnormal lab values
Correct answer: A concise synthesis that highlights key epidemiological, temporal, and clinical features
A problem representation distills the case into a one-line synthesis emphasizing the most discriminating features to guide differential diagnosis.
Question 6: A 67-year-old woman with rheumatoid arthritis presents with acute monoarthritis of the right knee. Which diagnosis must be excluded emergently?
- Septic arthritis (Correct answer)
- Gout flare
- Osteoarthritis exacerbation
- Reactive arthritis
Correct answer: Septic arthritis
Septic arthritis is a joint-destroying emergency that must be excluded by synovial fluid analysis whenever acute monoarthritis is present, especially in immunocompromised patients.
Question 7: Which feature on history is most helpful in distinguishing inflammatory from mechanical back pain?
- Morning stiffness lasting more than 1 hour that improves with activity (Correct answer)
- Pain that worsens with prolonged standing
- Pain relieved by rest
- Onset after a specific lifting injury
Correct answer: Morning stiffness lasting more than 1 hour that improves with activity
Morning stiffness lasting over 60 minutes that improves with activity is a hallmark of inflammatory back pain, as seen in ankylosing spondylitis.
Physician Assistant Formulating a Diagnosis 2
A 55-year-old man presents with exertional chest pain radiating to the left arm, diaphoresis, and nausea.
Which diagnosis should be highest on the differential?