Pseudogout in Primary Care Practice: An Approach to Diagnosis and Treatment.

Pseudogout refers to an autoinflammatory arthritis associated with the appearance of calcium pyrophosphate dihydrate crystals in the joint fluid. In acute pseudogout attacks patients typically endorse rapid onset of pain and swelling, at times following mechanical trauma to the joint. Physical exam reveals warmth, swelling with effusion, tenderness, and limited range of motion of the involved joint(s) which can mimic gout flares and an overlying soft tissue infection so maintaining a broad differential is important in the workup of pseudogout attacks. Risk factors for pseudogout include advancing age, osteoarthritis, mechanical joint trauma or history of meniscectomy, and primary hyperparathyroidism. Diagnosis requires synovial fluid analysis with direct visualization of rhomboid shaped calcium pyrophosphate crystals. Acute attacks are managed with low-dose colchicine, non-steroidal anti-inflammatory drugs, or corticosteroids (either intra-articular injection or systemic therapy). The ideal approach combines pharmacologic and supportive measures such as application of ice or cooling packs and temporary joint rest with weight restriction along with analgesic medications. Currently there are no long-term therapies that prevent calcium pyrophosphate crystal formation; however, research is underway for agents such as probenecid, phosphocitrate, methotrexate, and interleukin-1 antagonists.