Gout and pseudogout

Question 1

What are some risk factors for gout?

Answer 1

• Non-modifiable: male, age >50yrs, Fx of gout
• Modifiable: obesity, hypertension, diuretic use, alcohol, foods high in purines (seafood, red meats)

Question 2

What is the pathology of gout?

Answer 2

• prolonged hyperuricemia leads to the formation of monosodium urate crystals
• these deposit in the synovium, connective tissues, and kidneys
• (uric acid crystal deposition in the kidneys can cause interstitial nephritis, renal stones, and acute tubular damage)

Question 3

What are the clinical features of acute gout?

Answer 3

• sudden, severe pain in affected joint, joint swelling/erythema/warmth
• first MTP joint most commonly affected
• (acute gout attacks often subside after days or weeks)

Question 4

Extensive bone erosive destruction of the digits with soft tissue calcified tophi on plain radiograph…

Answer 4

• tophi = crystal deposition in soft tissues

Question 5

What investigations should be done for suspected gout?

Answer 5

• Joint aspiration and synovial fluid analysis under polarised light: negatively birefringent needle-shaped monosodium urate crystals
• Bloods: serum uric acid, ESR, CRP, WBC
• X-ray: normal joint space, soft tissue swelling, periarticular erosions

Question 6

Monosodium urate (MSU) crystals VS calcium pyrophosphate dihydrate (CPPD) crystals under polarised light…

Answer 6

Question 7

What condition (presents similar to gout) should be ruled out if suspected?

Answer 7

• septic arthritis
• urgent gram stain and culture
• (look for other features of sepsis: high temp., tachycardia, high resp. rate, low BP)
• (if in doubt, treat patients with antibiotics)

Question 8

What is the management for an acute gout attack?

Answer 8

• NSAIDs, or colchicine (if patient cannot take NSAIDs)
• intra-articular corticosteroid injections
• lifestyle: modifiable risk factors (lower alcohol, diet etc.)

Question 9

What prophylactic therapy should be given to manage chronic gout?

Answer 9

• Allopurinol (reduces uric acid production by inhibiting the enzyme xanthine oxidase)
• note: Febuxostat (another xanthine oxidase inhibitor)

Question 10

What is pseudogout (CPPD disease)?

Answer 10

• Calcium pyrophosphate dihydrate (CPPD) disease
• CPPD disease is an arthropathy associated with the deposition of CPPD crystals

Question 11

What are the clinical features of CPPD disease?

Answer 11

• more common in elderly
• Acute synovitis (pseudogout): pain, swelling, stiffness, erythema (most commonly affects wrists and knees)

Question 12

What investigations should be done for suspected CPPD disease?

Answer 12

• Joint aspiration and synovial fluid analysis under polarised light: weakly positively birefringent rhomboid (or rod) shaped CPPD crystals
• Radiology: similar to OA, with associated chondrocalcinosis

Question 13

What is the management for CPPD disease?

Answer 13

• NSAIDs or colchicine (if NSAIDs cannot be used)
• oral corticosteroids or intra-articular steroid injections (if NSAIDs and colchicine are contra-indicated)