AANP Family Nurse Practitioner (FNP) Certification ExamDiagnosisMedium
A 40-year-old male presents with a 2-day history of excruciating pain, swelling, and redness in his left great toe. He denies any recent trauma. On examination, the affected joint is exquisitely tender to touch, and the skin is taut and shiny. His medical history includes hypertension and hyperlipidemia, for which he takes hydrochlorothiazide and atorvastatin. Which of the following lab findings would most strongly support the suspected diagnosis?
- AElevated C-reactive protein (CRP)
- BErythrocyte sedimentation rate (ESR) of 45 mm/hr
- CPositive antinuclear antibody (ANA) test
- DSerum uric acid level of 9.2 mg/dL
Show answer & explanationAnswer & explanation
Correct answer: D. Serum uric acid level of 9.2 mg/dL
The patient's presentation is classic for an acute gouty attack (severe pain, redness, swelling of the great toe, history of hypertension/hyperlipidemia, and hydrochlorothiazide use which can elevate uric acid). An elevated serum uric acid level strongly supports this diagnosis, especially values > 6.8 mg/dL.
Why the other options are wrong
- A. Elevated CRP is a general marker of inflammation and would be present in gout but is not specific to the diagnosis.
- B. Elevated ESR is a general marker of inflammation, similar to CRP, and is not specific for gout.
- C. A positive ANA test is associated with autoimmune connective tissue diseases (e.g., lupus) and is not relevant to the diagnosis of gout.
Gout Diagnosis
Gout is an inflammatory arthritis caused by deposition of uric acid crystals in joints. Diagnosis is strongly supported by hyperuricemia and characteristic clinical presentation.
- Acute onset of severe monoarticular pain (often great toe).
- Associated with hyperuricemia (>6.8 mg/dL).
- Risk factors include diuretics, obesity, alcohol, high-purine diet.
Memory trick: Gout: Uric Acid is the 'U'ltimate clue.