Crystalline Arthritis

Gout, calcium pyrophosphate, basic calcium phosphate, and other crystal deposition diseases lead to local and/or systemic inflammation driven by aberrant innate immune responses to pathogenic crystal deposition. These crystals form within or around joints, causing arthritis and/or periarthritis. The pathways underlying these processes are still being elucidated, with the greatest amount of data available for gout, the most common crystal arthritis. Therapies for crystal arthropathies aim to reduce the duration and severity of acute flares and, in the case of gout, to prevent and dissolve pathogenic crystal deposits. Dietary approaches, focused on weight loss and cardiovascular health, are being studied for their benefits in reducing serum urate and improving elements of the metabolic syndrome. The role of genetics and the microbiome in gout holds promise for predicting progression from hyperuricemia to gout, as well as response to certain medications. Managing systemic inflammation is an area of focus in all crystal diseases. Our understanding of calcium pyrophosphate has evolved over the last decade, with increased understanding of crystal formation due to aberrant transport and extracellular production of inorganic pyrophosphate. As we look toward the future, exploring the pathogenic mechanisms underlying crystal deposition will yield medications aimed at dissolution.