Physician Assistant Formulating a Diagnosis 5 — Questions and Answers
Question 1: A PA is evaluating a 30-year-old woman with episodic hypertension, headaches, palpitations, and diaphoresis. Which secondary cause of hypertension should be included on the differential?
- Pheochromocytoma (Correct answer)
- Primary hyperaldosteronism
- Renal artery stenosis
- Cushing's syndrome
Correct answer: Pheochromocytoma
The triad of episodic hypertension, headache, and diaphoresis with palpitations is classic for pheochromocytoma, a catecholamine-secreting adrenal tumor.
Question 2: Which finding most strongly supports a diagnosis of acute appendicitis in a 25-year-old man with right lower quadrant pain?
- Migration of pain from periumbilical region to the RLQ with rebound tenderness and fever (Correct answer)
- Diffuse abdominal pain worsened by eating
- Pain that began in the RLQ without migration
- Intermittent crampy pain with diarrhea
Correct answer: Migration of pain from periumbilical region to the RLQ with rebound tenderness and fever
Pain migration from periumbilical to RLQ (McBurney's point), rebound tenderness, and fever represent the classic progression of acute appendicitis.
Question 3: In a patient with polyarthritis, which additional finding shifts the differential strongly toward systemic lupus erythematosus (SLE)?
- Malar rash, photosensitivity, and oral ulcers (Correct answer)
- Tophi on the ear helix
- Heberden's nodes
- Psoriatic skin plaques
Correct answer: Malar rash, photosensitivity, and oral ulcers
Malar rash, photosensitivity, and oral ulcers alongside polyarthritis fulfill multiple ACR/EULAR SLE classification criteria, making SLE the leading diagnosis.
Question 4: A PA evaluates two patients with identical presentations but very different pre-test probabilities for pulmonary embolism. How does pre-test probability affect diagnostic reasoning?
- A positive test result is more meaningful in a high-probability patient, raising post-test probability substantially (Correct answer)
- Pre-test probability does not affect interpretation of test results
- A negative test always rules out PE regardless of pre-test probability
- High pre-test probability means no further testing is needed
Correct answer: A positive test result is more meaningful in a high-probability patient, raising post-test probability substantially
Pre-test probability directly influences post-test probability through Bayes' theorem; the same positive test result carries more weight when disease is more likely before testing.
Question 5: A 58-year-old man with diabetes presents with a painless foot ulcer. His history of peripheral neuropathy is known. Which complication should be highest on the differential?
- Diabetic neuropathic ulcer with possible underlying osteomyelitis (Correct answer)
- Venous stasis ulcer
- Arterial insufficiency ulcer
- Pressure ulcer
Correct answer: Diabetic neuropathic ulcer with possible underlying osteomyelitis
Painless foot ulcers in diabetics with neuropathy are hallmarks of diabetic neuropathic ulcers, and osteomyelitis must be excluded given its high prevalence in this context.
Question 6: When formulating a diagnosis, which approach best reduces diagnostic error from the framing effect?
- Deliberately reframe the case from multiple perspectives to challenge the initial impression (Correct answer)
- Accept the referring clinician's working diagnosis without further analysis
- Focus only on the most recent test results
- Treat the patient based on the most likely diagnosis without further history
Correct answer: Deliberately reframe the case from multiple perspectives to challenge the initial impression
Reframing the case from different angles counteracts the framing effect by preventing the initial presentation of information from anchoring the diagnostic conclusion.
Question 7: A 22-year-old male athlete presents with sharp chest pain that worsens on inspiration and a friction rub on auscultation one week after a viral upper respiratory infection. Which diagnosis is most consistent?
- Acute pericarditis (Correct answer)
- Pleuritis
- Spontaneous pneumothorax
- Myocarditis
Correct answer: Acute pericarditis
Post-viral pleuritic chest pain with a pericardial friction rub is the classic presentation of acute pericarditis, often caused by viral inflammation of the pericardium.
Physician Assistant Formulating a Diagnosis 5
A PA is evaluating a 30-year-old woman with episodic hypertension, headaches, palpitations, and diaphoresis.
Which secondary cause of hypertension should be included on the differential?