Pseudokihti

Pseudokihti, known in English as pseudogout, or calcium pyrophosphate deposition disease (CPPD), is a crystal-induced inflammatory arthritis caused by deposition of calcium pyrophosphate dihydrate crystals in joint spaces. It is a non-gout form of inflammatory arthritis and can present as acute monoarthritis or evolve into a chronic inflammatory condition.

Most commonly, pseudokihti presents with an acute attack of joint swelling, warmth, redness, and severe pain, often affecting the knee but potentially involving any joint, including the wrist, ankle, and hip. Attacks can occur suddenly and may last from days to weeks. Recurrent flares are common, and some patients develop chronic joint symptoms over time.

Risk factors and causes include aging as a major factor, with higher prevalence in older adults. Associated metabolic and systemic conditions include hyperparathyroidism, hemochromatosis, hypomagnesemia, hypothyroidism, diabetes mellitus, and prior joint trauma. Genetic predisposition has also been observed in some families.

Pathophysiology and diagnosis rely on crystal analysis and imaging. CPPD crystals are typically rhomboid-shaped and exhibit weak positive birefringence under compensated polarized light. Synovial fluid analysis helps distinguish pseudokihti from septic arthritis and gout. Imaging, especially X-ray, may reveal chondrocalcinosis, calcification of articular cartilage or menisci, which supports the diagnosis.

Treatment focuses on managing acute flares and preventing recurrences. Acute management includes NSAIDs, colchicine, or corticosteroids (systemic or intra-articular). Rest, ice, and physical therapy support recovery. Long-term management may address underlying metabolic disorders and, in recurrent cases, low-dose colchicine for prophylaxis.

Prognosis varies; attacks typically resolve, but recurrences are common, and some patients develop chronic joint symptoms. Pseudokihti is a well-recognized cause of crystal arthritis, particularly in older adults.