Diagnosis and Management of Gout

Diagnostic Approach

The European League Against Rheumatism recommends joint aspiration with synovial fluid analysis for monosodium urate (MSU) crystals as the gold standard for diagnosing gout, with a sensitivity of 63-78% and specificity of 93-100% when performed by experienced operators 1, 2, 4
Synovial fluid aspiration and polarized light microscopy is the definitive diagnostic test and should be attempted in all cases of undiagnosed inflammatory arthritis, with the highest level of agreement among experts (8.8±0.3) 1, 3
MSU crystals appear needle-shaped with strong negative birefringence under polarized microscopy 4
Joint aspiration is particularly critical to rule out septic arthritis, which can coexist with gout and cannot be reliably excluded by clinical algorithms alone 3

A clinical diagnosis of gout is supported by monoarticular involvement of the foot (especially first metatarsophalangeal joint/podagra) or ankle joint, rapid onset of severe pain and swelling reaching maximum intensity within 6-24 hours, erythema overlying the affected joint, previous similar acute episodes of arthritis, male gender, and associated cardiovascular comorbidities and hyperuricemia 1, 2, 4, 5, 6
These clinical features have high sensitivity (98%) but very low specificity (23%), meaning they can suggest gout but cannot definitively confirm it without crystal identification 4

The European League Against Rheumatism recommends ultrasound as the preferred initial imaging modality, looking for the "double contour sign" at cartilage surfaces (pooled sensitivity 74%, specificity 88%) and tophi not evident on clinical examination 1, 3, 5
Dual-energy CT (DECT) has sensitivity of 85-100% and specificity of 83-92%, but is less sensitive for early gout 3, 5

Once gout is diagnosed, systematically assess for renal function (chronic kidney disease increases risk 4.95-fold), cardiovascular risk factors (hypertension, coronary heart disease, diabetes), obesity, medications (diuretics, low-dose aspirin), dyslipidemia, and metabolic syndrome 1, 4, 6

Document modifiable risk factors including alcohol consumption (particularly beer and spirits), diet (meat consumption, seafood, sugar-sweetened beverages), and diuretic use 1, 4, 6

For acute gout flare treatment, consider low-dose colchicine, NSAIDs, or glucocorticoids (intra-articular, oral, or intramuscular) depending on comorbidities, with the choice depending on renal function, cardiovascular disease, and gastrointestinal risk factors 6