Pseudogout Summary - Calcium Pyrophosphate Deposition Disease (CPPD)
Pathophysiology:
Pyrophosphate produced by chondrocytes likely precipitates with calcium to form CPP crystals, which then deposit and can activate inflammatory pathways, resulting in an acute arthritic flare
Think About CPPD When:
• Self-limited synovitis after surgery/trauma (> 65 years old)
• Unilateral swelling in weird joints (shoulders, wrists, elbows)
• Underlying disease states
1. Asymptomatic CPPD
Cartilage calcification appears as a linear opacity below the surface of articular cartilage
2. Acute CPP Crystal Arthritis
Monoarticular inflammatory arthritis, characterized by sudden onset of swelling, pain, loss of function, tenderness, and warmth
3. Chronic CPP Crystal Inflammatory Arthritis
• Resembles RA
• Chronic calcium pyrophosphate crystal inflammatory arthritis often involves the wrists and metacarpophalangeal joints ("pseudo-rheumatoid arthritis")
4. Osteoarthritis With CPPD
OA in atypical locations: Wrist, MCP or shoulder joints
Think of the "H's" especially if < 50 years age:
• Hemochromatosis
• Hyperparathyroidism
• Hypothyroidism
• Hypomagnesemia
Synovial Fluid:
• WBCs >2000-100,000/μL; neutrophil predominance
• CPP crystals
• Rhomboid shaped
• Weakly positively birefringent or not birefringent
• Gram stain, culture used to diagnose concomitant infection
Imaging may show chondrocalcinosis
Acute Pseudogout: Treatment
• Acute monoarticular CPPD disease
• Intra-articular glucocorticoids
• Acute polyarticular CPPD
• Systemic glucocorticoids
• NSAIDs
• Colchicine
• CPPD disease prophylaxis for ≥2 attacks
• Long-term colchicine
Crowned Dens Syndrome:
• A rare presentation of CPP crystal arthritis involving the C2 vertebra
• Radiographically it may present as calcification of the cartilage over the dens. Patients present with acute neck pain, fever, and headache, mimicking meningitis.
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