CalciumpyrophosphatDihydratKristallen

Calcium pyrophosphate refers to calcium salts of pyrophosphate, most commonly discussed in the form of calcium pyrophosphate dihydrate (CPPD) crystals. These crystals can deposit in joint cartilage and synovial fluid, giving rise to a condition known as calcium pyrophosphate deposition disease (CPPD), or pseudogout, when inflammatory arthritis develops.

CPPD crystals are typically rhomboid in shape and exhibit weak positive birefringence under polarized light, contrasting with the needle-shaped, negatively birefringent crystals seen in gout. Imaging often reveals chondrocalcinosis, which is calcification of the articular cartilage, visible on plain radiographs.

The disease is more prevalent in older adults and is associated with several metabolic or systemic conditions, including hyperparathyroidism, hemochromatosis, hypomagnesemia, and hypothyroidism, though many cases occur without an identifiable underlying disorder.

Clinical presentation usually involves acute or subacute arthritis, most commonly affecting the knee, wrist, or ankle. Patients may experience joint swelling, warmth, and pain, sometimes with recurrent flare-ups. Diagnosis relies on synovial fluid analysis showing CPPD crystals, alongside radiographic evidence of chondrocalcinosis and the exclusion of infection or gout.

Treatment focuses on symptom relief and management of underlying conditions. For acute attacks, nonsteroidal anti-inflammatory drugs (NSAIDs) are commonly used; colchicine can be employed for acute treatment or prophylaxis; intra-articular corticosteroids are effective for localized disease. Chronic management targets prevention of future flares and treatment of contributing metabolic abnormalities.

Prognosis varies with the pattern of involvement and response to therapy; some individuals experience infrequent symptoms, while others have recurrent or progressive joint disease.