|A.||Acute bacterial joint infection|
Acute bacterial joint infection
Hyaline cartilage degeneration
Uric acid overproduction
The image illustrates monosodium urate crystals, as seen in a fresh preparation of synovial fluid. This is gout.
Most patients with gout are overproducers of uric acid. Hyaline cartilage degeneration is typical of osteoarthritis, which usually has a bland synovial aspirate.
Antibodies to ANA are typical of lupus, rare in an elderly man, and not associated with crystalline fluid.
Bacterial joint infection would have a purulent synovial fluid.
Increased production of inorganic pyrophosphate is a cause of calcium pyrophosphate deposition disease (CPPD; pseudogout), another crystalline arthropathy. CPPD crystals are rod/rhomboid-shaped, weakly birefringent ( images below):