AANP Family Nurse Practitioner (FNP) Certification ExamAssessmentMedium
A 48-year-old male presents with acute onset of severe pain, swelling, and redness in his right great toe. He denies any trauma. He reports a history of occasional alcohol consumption and recently started a new medication for hypertension. On physical examination, the right great toe is exquisitely tender, warm, and erythematous. Which of the following diagnostic tests is most definitive for confirming the suspected diagnosis?
- AArthrocentesis with synovial fluid analysis
- BSerum uric acid level
- CPlain radiograph of the foot
- DErythrocyte sedimentation rate (ESR)
Show answer & explanationAnswer & explanation
Correct answer: A. Arthrocentesis with synovial fluid analysis
The patient's presentation (acute, monoarticular arthritis, particularly in the great toe, with severe pain, swelling, and redness) is highly suggestive of acute gout. While serum uric acid and X-rays can be supportive, arthrocentesis with synovial fluid analysis for negatively birefringent, needle-shaped urate crystals is the gold standard and most definitive diagnostic test for gout.
Why the other options are wrong
- B. Serum uric acid levels can be normal during an acute gout attack and are not definitive for diagnosis.
- C. Plain radiographs may show soft tissue swelling but are not diagnostic for acute gout and may only show changes in chronic gout.
- D. ESR is a general inflammatory marker and is not specific for gout.
Acute Gout Diagnosis
Acute gout is a painful inflammatory arthritis caused by the deposition of monosodium urate crystals in joints. It typically presents as a sudden, severe attack in a single joint, most commonly the great toe.
- Often triggered by alcohol, certain foods, or medications (e.g., diuretics).
- Arthrocentesis with synovial fluid analysis is the definitive diagnostic test.
- Characteristics of crystals: negatively birefringent and needle-shaped.
Memory trick: Gout's Got Crystals: Get a Fluid Sample!