Pseudogout

 

• Background

  • Aka chondrocalcinosis, pseudogout.
  • A crystal arthropathy, with deposition of calcium pyrophosphate released from damaged chondrocytes.
  • Can be primary, or secondary to osteoarthritis or a metabolic problem such as hyperparathyroidism, haemochromatosis, or hypomagnesaemia.

• Presentation

  • Acute monoarthritis: hot, red, swollen, painful joint.
  • Can also present with a chronic arthritis.
  • Usually affects knee, but can affect any limb joint. Can be oligoarticular.
  • May have systemic symptoms including fever.

• Investigations

  • Joint aspiration: +ve birefringent rhomboid-shaped urate crystals under light microscopy.
  • X-ray: linear, opaque deposits in joint.
  • May have ↑WBC.
  • Investigate underlying cause: PTH, Ca2+, Mg2+, iron.

• Management

  Acute:

  • NSAIDs or steroids (intra-articular, IM, or PO).
  • Colchicine 2nd line.
  • Splinting and joint aspiration may also help.

  Long-term:

  • NSAIDs
  • Colchicine 2nd line.
  • Joint replacement if medically refractory.