Can you have gout without hyperuricemia (elevated uric acid levels)?

Can You Have Gout Without Having High Uric Acid?

Yes, you can have gout without having elevated uric acid levels, as serum uric acid levels may be normal during acute gout attacks in approximately 10% of patients with gout. 1

Relationship Between Serum Uric Acid and Gout

Serum uric acid (SUA) levels have a complex relationship with gout:

• While hyperuricemia is the most important risk factor for gout, SUA levels alone cannot confirm or exclude a diagnosis of gout 1
• During acute gout attacks, SUA may be normal in some patients 1
• Studies show that roughly 10% of people with gout have SUA levels below 6 mg/dL during gout flares 1

Why SUA May Be Normal During Gout Attacks

Several mechanisms explain why SUA may be normal during an acute gout attack:

• Negative acute phase response: SUA behaves as a negative acute phase reactant, being temporarily lowered during episodes of acute inflammation and stress 1
• Increased renal excretion: There is increased renal excretion of uric acid during acute gout episodes 1
• Recent lifestyle changes: Prior risk factors for hyperuricemia may have been modified or removed at the time of presentation (e.g., cessation of diuretic use, reduction of obesity, decreased beer intake) 1

Diagnostic Implications

The possibility of normal SUA during gout attacks has important diagnostic implications:

• Gold standard diagnosis: Identification of monosodium urate (MSU) crystals in synovial fluid or tophus aspirates remains the definitive diagnostic method 1
• Limited diagnostic value: SUA has limited diagnostic value, especially during an acute attack of gout 1
• Sensitivity and specificity: Using a cut-off level of 6 mg/dL (360 μmol/L) for SUA has only moderate sensitivity (0.67) and specificity (0.78) for diagnosing gout 1

Clinical Approach When Suspecting Gout with Normal SUA

When a patient presents with symptoms suggestive of gout but has normal SUA levels:

1. Joint aspiration: Attempt to obtain synovial fluid for MSU crystal identification whenever possible 1
2. Imaging: Consider advanced imaging techniques like ultrasound or dual-energy CT to search for MSU crystal deposition 1
3. Repeat SUA testing: Check SUA levels during intercritical periods (between attacks) when they are more likely to be elevated 1
4. Clinical features: Evaluate for typical clinical manifestations of gout (podagra, rapid onset of severe pain, erythema) 1

Important Caveats

• Normal SUA during an acute attack does not exclude a diagnosis of gout 1
• Conversely, hyperuricemia alone is insufficient for diagnosing gout, as many people with high SUA never develop gout 1
• Treating based on SUA levels alone without crystal identification may lead to misdiagnosis and inappropriate management 1

In conclusion, while hyperuricemia is strongly associated with gout, the relationship is not absolute. The diagnosis of gout should be based on crystal identification whenever possible, and clinicians should be aware that normal SUA levels during an acute attack do not rule out gout.