A 52-year-old male presents with acute severe pain, swelling, and erythema of the right first metatarsophalangeal joint. Arthrocentesis demonstrates needle-shaped, negatively birefringent crystals under polarized light. What is the diagnosis?
Answer and explanation
Correct answer: C. Acute gouty arthritis
- Step 1: Acute podagra with needle-shaped monosodium urate crystals displaying strong negative birefringence (yellow when parallel to slow axis of compensator) is diagnostic of acute gouty arthritis.
- Step 2: Initial treatment includes NSAIDs, colchicine, or corticosteroids.
Answer
Acute gouty arthritis.
Why not the others: 'Pseudogout' exhibits rhomboid-shaped, weakly positively birefringent crystals (blue when parallel); 'Septic arthritis' yields turbid fluid with purulent leukocyte counts and positive Gram stain/culture; 'Rheumatoid flare' does not feature birefringent crystals.
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