Pseudogicht

Pseudogicht, also known as pseudogout, is an inflammatory arthritis caused by deposition of calcium pyrophosphate dihydrate crystals in joint cartilage and synovial fluid. The condition presents with acute joint swelling and pain that can resemble gout but is driven by different crystal morphology and biochemical processes.

Crystal deposition occurs mainly in hyaline and fibrocartilage, forming rhomboid-shaped crystals that are weakly positively birefringent under polarized light. Pseudogicht is commonly associated with aging and several metabolic or systemic disorders, such as hyperparathyroidism, hemochromatosis, hypomagnesemia, and hypophosphatasia. Joint injury or recent surgery can also predispose to flares.

Clinically, pseudogicht most often affects the knee, but can involve other joints such as the wrists or hips. Patients experience abrupt onset of joint warmth, swelling, tenderness, and limited movement. Attacks may be isolated or recur over time, and some individuals develop a chronic, fluctuating arthropathy.

Diagnosis relies on synovial fluid analysis showing CPPD crystals: rhomboid-shaped and positively birefringent. Imaging can support the diagnosis by revealing chondrocalcinosis, or calcification of articular cartilage and menisci, on plain radiographs. Ultrasound or MRI may detect crystal deposition or related joint changes; it helps distinguish pseudogicht from gout or septic arthritis.

Treatment focuses on symptom control and prevention of flares. Acute attacks are typically managed with NSAIDs or colchicine; intra-articular corticosteroids or systemic steroids are used when appropriate. For recurrent disease, low-dose colchicine prophylaxis and treatment of underlying metabolic conditions are considered. Rehabilitation and activity modification support joint function.

Prognosis varies with age and comorbidity; many individuals experience intermittent flares, while some develop chronic CPPD-associated arthritis.