What are the diagnostic criteria and treatment options for gout?

Gout Diagnosis and Treatment

The definitive diagnosis of gout requires demonstration of monosodium urate (MSU) crystals in synovial fluid or tophus aspirates using polarizing microscopy, which should be performed whenever diagnostic testing is necessary in patients with suspected acute gout. 1, 2

Diagnostic Criteria

Gold Standard Diagnostic Test

• Synovial fluid analysis with identification of MSU crystals is the reference standard for gout diagnosis, with sensitivity ranging from 63-78% and specificity from 93-100% 1, 2
• MSU crystals appear as needle-shaped, negatively birefringent crystals under polarizing microscopy 2

Clinical Diagnosis

• In acute attacks, rapid development of severe pain, swelling, and tenderness reaching maximum within 6-12 hours, especially with overlying erythema, is highly suggestive of crystal inflammation 1
• For typical presentations (such as recurrent podagra with hyperuricemia), clinical diagnosis alone is reasonably accurate but not definitive without crystal confirmation 1
• Clinical features with high diagnostic value include:
  • Podagra (first metatarsophalangeal joint inflammation) 1
  • Presence of tophi (strongest predictive value with odds ratio 7.29) 1
  • Resolution of pain within 2 weeks 1
  • Rapid onset of severe pain reaching maximum within hours 1

Alternative Diagnostic Methods

• Several clinical algorithms have demonstrated good sensitivity and specificity (>80%) compared to synovial fluid MSU crystal analysis 1
• Dual-Energy Computed Tomography (DECT) shows sensitivity of 85-100% and specificity of 83-92%, but is less sensitive in patients with recent-onset acute gout 1
• Ultrasonography shows variable sensitivity (37-100%) and specificity (68-97%), with pooled sensitivity of 74% and specificity of 88% 1

Risk Factors and Associated Conditions

• Male sex (relative risk 7.64) 1
• Obesity (relative risk 3.81) 1
• Hypertension (relative risk 3.93) 1
• Chronic renal failure (relative risk 4.95) 1
• Alcohol consumption, especially beer 3
• Diet rich in meat and seafood 1
• Diuretic use 1
• High-fructose corn syrup consumption 3

Treatment Options

Acute Gout Flare Management

• First-line options include:
  • Nonsteroidal anti-inflammatory drugs (NSAIDs) - preferable to colchicine due to more favorable side effect profile 3, 4
  • Colchicine - effective when used in low-dose regimen (1.2 mg, then 0.6 mg one hour later for total 1.8 mg) 5
  • Corticosteroids (systemic or intra-articular) - particularly useful when NSAIDs or colchicine are contraindicated 3, 4

Long-term Management

• Indications for urate-lowering therapy include:

  • Two or more gout flares per year 3, 6
  • Presence of tophi 3, 6
  • Chronic kidney disease 3, 6
  • Urolithiasis 3, 6
  • Joint damage 3, 6

• First-line urate-lowering medications:

  • Allopurinol - most commonly used first-line agent 3, 7
  • Febuxostat - effective alternative but associated with increased cardiovascular mortality 6
  • Probenecid - reserved for patients who cannot tolerate first-line agents 3

• Prophylaxis during initiation of urate-lowering therapy:

  • Low-dose colchicine, NSAIDs, or corticosteroids should be used concurrently to prevent flares 3
  • Continue prophylaxis for at least 3-6 months after achieving target uric acid levels 3

Clinical Considerations and Pitfalls

• Joint aspiration may be technically challenging in smaller joints but is essential when septic arthritis is suspected 2
• Hyperuricemia alone is not sufficient for gout diagnosis as many people with elevated serum uric acid never develop gout 1
• Clinical algorithms have higher sensitivity in patients with longer disease duration (>2 years) than in those with recent-onset symptoms 1
• Colchicine dosing must be adjusted in patients with renal or hepatic impairment and when used with certain medications (especially CYP3A4 inhibitors) 5
• Treatment should focus not only on acute flare management but also on addressing modifiable risk factors and comorbidities 8, 7