Calcium pyrophosphate deposition disease

Name the clinical phenotype before treating. Acute CPP crystal arthritis begins over hours with swelling, heat and severe pain, most often in a knee or wrist but also ankle, elbow, shoulder or hip. Chronic CPP inflammatory arthritis produces persistent or fluctuating wrist, MCP and large-joint synovitis. Osteoarthritis with CPPD involves unusual sites or compartments, including radiocarpal, second and third MCP, glenohumeral and lateral knee disease. Incidental chondrocalcinosis without symptoms needs explanation, not anti-inflammatory treatment.

Examine for a true effusion and restriction of both passive and active movement. Map every inflamed joint because oligoarticular attacks occur. Look for bony enlargement, wrist collapse, second- and third-MCP involvement and haemochromatosis signs. In acute neck pain, assess meningism, temporal arteries, neurological deficits and infection. Crowned dens syndrome classically causes severe upper-neck pain and restricted rotation in an older adult, sometimes with fever and high CRP.

Synovial fluid is the diagnostic reference when uncertainty matters. CPP crystals are typically rhomboid or rod-shaped and weakly positively birefringent, appearing blue when parallel and yellow when perpendicular to the compensator axis. They are less conspicuous than urate crystals and may be missed. Request Gram stain, culture and cell count with microscopy because infection and crystals coexist. No white-cell threshold safely excludes bacterial disease.

Use metabolic testing selectively. In onset under sixty, extensive deposition, recurrent attacks or suggestive family or systemic history, measure corrected calcium, magnesium, phosphate, alkaline phosphatase, PTH, ferritin and transferrin saturation. Low alkaline phosphatase can suggest hypophosphatasia; high calcium with non-suppressed PTH suggests hyperparathyroidism; a high transferrin saturation directs HFE assessment. Treating these conditions improves systemic risk but may not reverse established cartilage deposits.

For a single accessible joint, aspirate to relieve pressure and establish culture and crystal data, then inject intra-articular corticosteroid once infection is reasonably excluded. This limits systemic exposure in an older patient with multiple comorbidities. Local cool packs and short rest help initially; begin gentle range and load progression as pain permits so immobilisation does not create weakness and stiffness.

When local injection is not feasible, use the lowest-risk short systemic option. Colchicine 500 micrograms twice daily for a short course is commonly used off-label; avoid the historic high-dose strategy and check renal, hepatic and interaction risk. A short NSAID course with gastroprotection or prednisolone 20–30 mg daily for three to five days are alternatives under local practice. Revisit sepsis if inflammation fails to settle rather than simply extending treatment.

Recurrent attacks may justify colchicine 500 micrograms once or twice daily prophylaxis under rheumatology review. Persistent inflammatory CPPD has a weak evidence base; EULAR permits NSAID with gastroprotection, low-dose colchicine, low-dose corticosteroid and selected hydroxychloroquine or methotrexate approaches. Define whether the goal is fewer acute attacks or control of true ongoing synovitis, and stop an ineffective toxic trial.

There is no licensed crystal-depleting therapy. Do not prescribe allopurinol for CPP crystals unless the patient separately has gout. Treat coexisting osteoarthritis with tailored strengthening, aerobic activity, weight support when relevant, walking aids, topical NSAID and surgical referral based on symptoms and function. Review metabolic disease, falls and medicine burden, because repeated acute-care prescribing can be more harmful than the deposits themselves.