gout

Question 1

definition of gout

Answer 1

Gout is a syndrome characterised by: hyperuricaemia and deposition of urate crystals causing attacks of acute inflammatory arthritis; tophi around the joints and possible joint destruction; renal glomerular, tubular and interstitial disease; and uric acid urolithiasis. The disease most commonly affects the first toe (podagra), foot, ankle, knee, fingers, wrist, and elbow; however, it can affect any joint.

Complications include joint destruction, kidney disease, and urolithiasis.

Question 2

risk factors

Answer 2

• older age
• male sex
• menopausal status
• consumption of meat, seafood, alcohol
• use of diuretics
• use of cyclosporine or tacrolimus (Lead to increased tubular re-absorption of urate as well as decreased glomerular filtration and interstitial nephropathy.)
• use of pyrazinamide (TB medication) (Increases urate re-absorption.)
• use of aspirin (Doses of ≤325 mg elevate urate levels, while higher doses have uricosuric effects and lead to lower urate levels.)
• genetic susceptibility
• high cell turnover rate (Conditions that lead to high endogenous purine metabolism include haematological malignancies, myeloproliferative disorders, psoriasis, and chemotherapy-induced cell death.)

Question 3

symptoms and signs

Answer 3

• rapid onset severe pain (during gout attack)
• joint stiffness (morning stiffness -> inflammatory sign)
• foot joint distribution
• mono or oligo arthropathy (can develop into polyarthropathy in elderly)
• swelling and joint effusion
• tenderness
• tophi
• erythema and warmth

Question 4

investigations

Answer 4

1st investigation: arthrocentesis with synovial fluid analysis
(Confirms the diagnosis, and will exclude septic arthritis and differentiate gout from pseudogout (calcium pyrophosphate deposition disease) => WCC count >2.0 x 10^9/L (2000/mm^3 or 2000/microlitre; mean, 20,000/mm^3 or 20,000/microlitre); strongly negative birefringent needle-shaped crystals under polarised light

others:

• uric acid level (at least 2 weeks after the attack resolves, as it may be falsely low or normal during the attack.) => >416 micromol/L (7 mg/dL) in men; >360 micromol/L (6 mg/dL) in women
• x ray of affected joint => periarticular erosions
• ultrasound => erosions, tophi, double contour line