Pseudogout

Question 1

Define pseudgout

Answer 1

PSEUDOGOUT:

Arthritis associated with deposition of calcium pyrophosphate dihydrate (CPPD) crystals in the joint cartilage

Question 2

Explain the aetiology/risk factors of pseudogout

Answer 2

• Usually spontaneous and self-limiting but can be provoked by illness, surgery or trauma
• CPPD crystal formation is initiated in cartilage located near the surface of chondrocytes
• Shedding of crystals into the joint cavity triggers an inflammatory response and leads to acute arthritis

Common in older women

RISK FACTORS:

• Haemochromatosis
• Hyperparathyroidism
• FHx of CPPD
• Osteoarthritis
• Hypomagnesaemia
• Hypophosphatasia
• Trauma/previous joint surgery
• Old age

Question 3

Recognise the presenting symptoms of crystal arthropathy (gout, pseudogout)

Answer 3

• Painful, red & swollen joints
• Worsening of osteoarthritis
• Shoulder, knee, MCP, elbow (polyarticular)
• Low-grade fever

Question 4

Recognise the signs of crystal arthropathy (gout, pseudogout) on physical examination

Answer 4

• Painful, red & swollen joints
• Shoulder, knee, MCP, elbow involvement (polyarticular)
• Low-grade fever

Question 5

Identify appropriate investigations for crystal arthropathy (gout, pseudogout) and interpret the results

Answer 5

• Synovial fluid assessment
  
  • Presence of crystals that are (weakly) positive birefringent on polarised light microscopy
  • Rhomboid/rod crystals are seen
• X-ray of afected joint:
  
  • Chondrocalcinosis
• Calcium, PO4 & PTH to exclude HPT
• Iron studies: exclude hamochromatosis

Question 6

Management

Answer 6

Colchicine long term