Physician Assistant Formulating a Diagnosis 4 — Questions and Answers
Question 1: A PA is evaluating a 72-year-old with confusion, fever, and costovertebral angle tenderness. Which diagnosis best explains this triad?
- Urosepsis (Correct answer)
- Bacterial meningitis
- Viral encephalitis
- Hypertensive encephalopathy
Correct answer: Urosepsis
Confusion with fever and CVA tenderness in an elderly patient points to urosepsis—a urinary source of infection causing systemic inflammatory response.
Question 2: Which pattern of joint involvement is most consistent with a diagnosis of rheumatoid arthritis?
- Symmetric small joint polyarthritis affecting MCPs and PIPs with morning stiffness (Correct answer)
- Asymmetric large joint arthritis affecting weight-bearing joints
- Monoarthritis of the first MTP joint
- Migratory arthritis following a gastrointestinal infection
Correct answer: Symmetric small joint polyarthritis affecting MCPs and PIPs with morning stiffness
Rheumatoid arthritis classically presents with symmetric polyarthritis of the MCPs and PIPs accompanied by prolonged morning stiffness.
Question 3: A PA applies the principle of parsimony (Occam's Razor) in formulating a diagnosis. What does this principle suggest?
- One unifying diagnosis should explain all of the patient's findings when possible (Correct answer)
- Multiple diagnoses must always be considered simultaneously
- The rarest diagnosis should be prioritized
- The most expensive test should be ordered first
Correct answer: One unifying diagnosis should explain all of the patient's findings when possible
Occam's Razor in clinical reasoning favors a single unifying diagnosis over multiple separate diagnoses when the clinical evidence supports it.
Question 4: A 45-year-old woman with a history of migraines presents with a new-onset headache that is different from her usual migraines. What is the most important next step in diagnostic reasoning?
- Treat this headache as a new diagnostic problem and evaluate for secondary causes (Correct answer)
- Prescribe her usual migraine treatment since she has a known history
- Order an MRI immediately without further history
- Reassure her that migraines can vary in presentation
Correct answer: Treat this headache as a new diagnostic problem and evaluate for secondary causes
A change in headache pattern in a known migraineur requires treating the presentation as a new diagnostic problem to exclude secondary causes such as intracranial pathology.
Question 5: Which feature distinguishes cardiac syncope from vasovagal syncope during diagnostic formulation?
- Syncope occurring without prodrome during exertion or at rest (Correct answer)
- Syncope preceded by nausea and diaphoresis in a warm environment
- Syncope triggered by prolonged standing
- Syncope with slow recovery over several minutes
Correct answer: Syncope occurring without prodrome during exertion or at rest
Syncope without prodrome during exertion or at rest suggests an arrhythmic or structural cardiac cause and requires urgent cardiac evaluation.
Question 6: A PA's differential diagnosis is overly influenced by a recently diagnosed patient with the same condition. Which cognitive bias is most likely operating?
- Availability heuristic (Correct answer)
- Anchoring bias
- Framing effect
- Overconfidence bias
Correct answer: Availability heuristic
The availability heuristic causes clinicians to overestimate the likelihood of diagnoses that come easily to mind, often due to recent or vivid experiences.
Question 7: A 60-year-old smoker presents with progressive dyspnea, digital clubbing, and bibasilar dry crackles on auscultation. Which diagnosis should be prioritized?
- Idiopathic pulmonary fibrosis (Correct answer)
- Chronic obstructive pulmonary disease
- Congestive heart failure
- Asthma
Correct answer: Idiopathic pulmonary fibrosis
Bibasilar Velcro crackles, clubbing, and progressive dyspnea in an older smoker form the classic triad pointing to idiopathic pulmonary fibrosis.
Physician Assistant Formulating a Diagnosis 4
A PA is evaluating a 72-year-old with confusion, fever, and costovertebral angle tenderness.
Which diagnosis best explains this triad?