Which crystal type is associated with gout?

Which crystal type is associated with gout?

• A. Calcium pyrophosphate dihydrate crystals; rhomboid-shaped and positively birefringent
• B. Cholesterol crystals; plate-like and non-birefringent
• C. Uric acid crystals; rhomboid-shaped and positively birefringent
• D. Monosodium urate crystals; needle-shaped and negatively birefringent

Answer: (D)

Gout is defined by deposition of monosodium urate crystals in joints due to high uric acid levels. Under polarized light, these crystals are needle-shaped and negatively birefringent, meaning they appear blue when aligned with the slow optic axis and yellow when perpendicular. This combination of slender, needle-like appearance and negative birefringence is characteristic of monosodium urate crystals. Other crystal types produce different appearances: calcium pyrophosphate dihydrate crystals are rhomboid and positively birefringent (pseudogout), and cholesterol crystals are plate-like and non-birefringent. So the finding that matches gout best is monosodium urate crystals with needle shape and negative birefringence.

Gout is defined by deposition of monosodium urate crystals in joints due to high uric acid levels. Under polarized light, these crystals are needle-shaped and negatively birefringent, meaning they appear blue when aligned with the slow optic axis and yellow when perpendicular. This combination of slender, needle-like appearance and negative birefringence is characteristic of monosodium urate crystals. Other crystal types produce different appearances: calcium pyrophosphate dihydrate crystals are rhomboid and positively birefringent (pseudogout), and cholesterol crystals are plate-like and non-birefringent. So the finding that matches gout best is monosodium urate crystals with needle shape and negative birefringence.