Synovial xanthomatosis: are there clues to mechanisms for this rare disease?

We report a 64-year-old man with arthritis and nodules to describe that this picture can be caused by normo-lipidemic xanthomas. Light and electron microscopy (EM) plus polymerase chain reaction (PCR) studies were performed for diagnosis and investigation. These showed features typical of xanthomas plus PCR and EM evidence of possible infection with Chlamydia pneumoniae as a pathogenetic mechanism deserving consideration. With such rare diseases, any clues to possible mechanisms seem important to record and thus to encourage future investigations. This uncommon cause of arthritis and nodules had been confused with rheumatoid arthritis by others in this case.

Clinical diagnostic criteria for gout: comparison with the gold standard of synovial fluid crystal analysis.

BACKGROUND: Several classification or diagnostic criteria sets for gout have been proposed but none validated. OBJECTIVE: This small pilot study considered urate crystal identification as the gold standard for diagnosis and compared the clinical aspects of 3 proposed criteria sets with that standard. METHODS: Eighty-two subjects who had synovial fluid analyses in a VA medical center were studied. ARA (ACR), Rome, and New York clinical criteria sets and individual criteria were recorded in the 30 patients who had urate crystals versus the remainder with no urate crystals. RESULTS: Presence of 2 of 3 Rome clinical criteria had the highest positive predictive value at 76.9%. None of the 3 studied criteria sets were more than 70% sensitive or 88.5% specific. The clinical features of the ARA (ACR) preliminary classification criteria had 70% sensitivity and 78.8% specificity. CONCLUSIONS: The various proposed clinical criteria can provide support for a diagnosis or exclusion of gout, but unless improved criteria can be developed crystal identification should remain the gold standard.