More image challenges to come, but I still have some friends who haven’t taken their USMLE Step 1 exam, and a question like this may be good practice.
Case: A slender 23 year old white male presents to your office reporting general malaise and fever. He has been feeling crummy for a while, but thought his symptoms would subside on their own (as they have in the past). He also reports several episodes of having trouble “catching his breath” in the past few months and is worried that he doesn’t feel like a man his age should.
Review of systems:
- General fatigue (compared to the previous few years)
- Weight loss of ~12lbs in the past 6-7 months, unintentional
- Several episodes of SOB
- No blood or mucous noticed in the stool
- Back stiffness over the past 3 months
Physical exam, labs, etc.:
- Cervical & thoracic spine display limited extension
- Tenderness to palpation, mostly over the lumbosacral area (lower back)
- Peripheral joint exams are unremarkable for pain or range of motion
- Mild abdominal tenderness to deep palpation, without rebound or guarding
- Laboratory studies show a mild anemia: Hemoglobin 11 g/dL (low), Hematocrit 33% (low), PLT 425,000 (high)
- Stool is positive for occult blood
You schedule a colonoscopy for this patient. In the interim, which of the following would be of highest value for diagnosis?
A) Blood culture
B) Stool culture
C) HLA-B27 antigen test
D) B12 absorption study
E) A trial of gluten avoidance
F) Anti-nuclear antibody (ANA) test
Leave your answer below and check back in 24-48 hours for the answer & explanation – good luck!