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Pseudogout is a crystal-induced arthropathy caused by deposition of calcium pyrophosphate dihydrate (CPPD) crystals within joints, fibrocartilage, and hyaline cartilage.

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The term “pseudogout” refers to the acute arthritis clinically resembling gout, while the broader entity is called CPPD deposition disease (CPPD arthropathy).

https://www.youtube.com/watch?v=SDhMFzjCVYI

https://www.youtube.com/watch?v=Doc_IQdDU6s

https://www.youtube.com/watch?v=h2DnRPrRWl0

Etiopathogenesis

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Crystal formation: Due to imbalance in inorganic pyrophosphate metabolism → deposition of CPPD crystals in cartilage.

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Risk factors / associations:

• Increasing age (prevalence rises >60 years).
• Joint trauma/osteoarthritis.
• Metabolic/endocrine disorders:
  • Hyperparathyroidism
  • Hemochromatosis
  • Hypophosphatasia
  • Hypomagnesemia
  • Wilson’s disease
• Genetic predisposition in some families (early-onset CPPD).

Clinical Features

| Acute pseudogout attack | • Monoarticular arthritis, most commonly affecting the knee; also wrist, shoulder, ankle. • Sudden onset of pain, swelling, warmth, and decreased mobility. • Attacks may be precipitated by surgery, trauma, or intercurrent illness. | | --- | --- | | Chronic CPPD arthropathy | • Mimics osteoarthritis or rheumatoid arthritis with progressive joint degeneration. • Involves atypical joints such as radiocarpal, MCP, or shoulder. | | Asymptomatic chondrocalcinosis | Radiological finding without clinical arthritis. |

Radiology