Which finding in synovial fluid supports a diagnosis of gout?

Which finding in synovial fluid supports a diagnosis of gout?

• A. Uric acid crystals in synovial fluid
• B. Calcium pyrophosphate crystals
• C. Bacteria in the fluid
• D. No crystals present

Answer: (A)

Gout is diagnosed by directly identifying monosodium urate crystals deposited in the joint. When synovial fluid is examined, these crystals are typically needle-shaped and show negative birefringence under polarized light, which is characteristic of gout. This finding directly ties the joint pain to crystal deposition from high uric acid levels, distinguishing gout from other conditions. Calcium pyrophosphate crystals would point to pseudogout, which is a different crystal arthropathy. Bacteria in the fluid suggests septic arthritis, not gout. If no crystals are seen, gout is less certain, though possible in some cases. So, finding uric acid (monosodium urate) crystals in synovial fluid best supports a gout diagnosis.

Gout is diagnosed by directly identifying monosodium urate crystals deposited in the joint. When synovial fluid is examined, these crystals are typically needle-shaped and show negative birefringence under polarized light, which is characteristic of gout. This finding directly ties the joint pain to crystal deposition from high uric acid levels, distinguishing gout from other conditions.

Calcium pyrophosphate crystals would point to pseudogout, which is a different crystal arthropathy. Bacteria in the fluid suggests septic arthritis, not gout. If no crystals are seen, gout is less certain, though possible in some cases. So, finding uric acid (monosodium urate) crystals in synovial fluid best supports a gout diagnosis.