Pseudogout: Uncommon and Under-Recognized

Pseudogout or calcium pyrophosphate deposition (CPPD) disease is an uncommon and often under-recognized resentation in primary care. Patients may initially develop asymptomatic crystal deposition, but these changes can evolve to synovitis, arthritis, and cartilage calcification. An initial differential diagnosis includes traditional gout, osteoarthritis, rheumatoid arthritis, septic arthritis, and Lyme disease. Acute attacks of CPPD may be indistinguishable from these conditions clinically, and a definitive diagnosis requires synovial fluid analysis. Fluid should be microscopically analyzed for cell count, crystal analysis under compensated polarizing microscopy, Gram stain, and culture. CPPD crystals are weakly birefringent under polarized light and have a rhomboid or rod-shaped appearance. No therapy is proven optimal, so CPPD treatment is instead tailored to symptoms, with goals of controlling acute pain, preventing additional attacks, and impeding the degenerative joint disease associated with CPPD disease arthropathy. Current treatment methods include intra-articular corticosteroid injections, NSAIDs, DMARDs, OMT, and in severe, refractory cases, surgery.