Calcium pyrophosphate deposition disease (CPPD) is a condition characterized by the deposition of calcium pyrophosphate dihydrate (CPP) crystals in the joints and soft tissues. It is often referred to as pseudogout when it causes acute inflammatory arthritis, but it also encompasses other clinical manifestations, such as chronic arthritis and asymptomatic crystal deposition.

Pathophysiology CPP crystals form due to an imbalance in pyrophosphate metabolism. These crystals are deposited in cartilage (chondrocalcinosis) and other joint structures, leading to inflammation and tissue damage. Epidemiology CPPD primarily affects older adults, with incidence increasing after the age of 60. Risk factors include: Aging (most significant factor). Joint trauma or surgery. Metabolic disorders, such as: Hyperparathyroidism. Hemochromatosis. Hypomagnesemia. Hypophosphatasia. Diabetes mellitus. Genetic predisposition in familial cases. Clinical Manifestations Asymptomatic CPPD

Incidentally discovered chondrocalcinosis on imaging without symptoms. Acute CPP crystal arthritis (Pseudogout)

Sudden onset of monoarthritis or oligoarthritis. Commonly involves large joints (e.g., knee, wrist). Symptoms: Pain, swelling, warmth, and erythema, resembling gout. Chronic CPP crystal inflammatory arthritis

Mimics osteoarthritis or rheumatoid arthritis. Joint stiffness, pain, and mild swelling. Often polyarticular. Osteoarthritis with CPPD

CPPD can coexist with or exacerbate osteoarthritis. Rare manifestations

Spinal involvement (crowned dens syndrome causing neck pain and fever). Tendinitis or bursitis. Diagnosis Clinical Evaluation

Acute joint pain, often with a history of joint trauma or surgery. Chronic arthritis with signs of cartilage degeneration. Synovial Fluid Analysis

Detection of positively birefringent, rhomboid-shaped crystals under polarized light microscopy is diagnostic. Imaging

X-rays: Chondrocalcinosis (calcification of cartilage). Joint degeneration and subchondral cysts. Ultrasound: Crystal deposits in cartilage or tendons. CT or MRI: Rarely needed, used for complicated cases. Laboratory Tests

Exclude secondary causes by testing for serum calcium, magnesium, phosphate, ferritin, and alkaline phosphatase levels. Rule out infection and rheumatoid arthritis if suspected. Management Acute CPP Crystal Arthritis Nonsteroidal anti-inflammatory drugs (NSAIDs): First-line for pain and inflammation. Colchicine: Effective for prophylaxis or mild attacks. Glucocorticoids: Intra-articular injections for localized arthritis. Systemic steroids for severe polyarthritis. Aspiration of synovial fluid: Relieves joint pressure and confirms diagnosis. Chronic CPPD Symptom management: NSAIDs or colchicine for flare prevention. Analgesics (e.g., acetaminophen) for chronic joint pain. Physical therapy: Maintain joint function and mobility. Address underlying metabolic conditions: Correct hypomagnesemia or hyperparathyroidism if present. Prognosis CPPD is a chronic condition with variable progression. Acute flares can be managed effectively, but chronic disease may lead to joint damage and reduced quality of life. Future Directions Research on crystal dissolution and targeted therapies for inflammation holds promise for better management of CPPD in the future.