Diagnosis
One important key to the early and effective management of gout is an accurate diagnosis. EULAR recommendations have been made regarding the sensitivity and specificity of certain clinical features and their use in establishing a diagnosis of gout.[14] The history of episodic self-limited joint pain, swelling and erythema is highly sensitive for clinical gout, but not specific for gout. More specific, but still not diagnostic, features for gout include a history of podagra and the presence of a suspected tophus. There is the reasonable specificity of about 80–90% for these clinical markers in making a provisional diagnosis.[15] If however, the course and response to appropriate treatment is not as anticipated, it is recommended that undiagnosed inflamed joints be examined by an experienced laboratory for monosodium urate (MSU) crystals as this permits a definite diagnosis.[15] Identification of MSU crystals in synovial fluid from asymptomatic joints may also allow definite diagnosis.[14,16]
Serum uric acid levels, although elevated at some time in all patients with gout and helpful in diagnosis, should not be relied upon solely in the diagnosis of gout as they may be normal during an acute flare, and hyperuricemia can be present in asymptomatic individuals.[17] Radiographs are not typically useful early in the diagnosis of acute gout although they may help to rule out other causes of joint pain and swelling.
Even with visualisation of crystals, other coexisting causes of joint pain and swelling should be considered, such as trauma and infection. Septic arthritis and gout have been described together, although the occurrence is rare.[18,19]
In patients diagnosed with gout, care should be taken to assess for underlying risk factors for the development of hyperuricemia and gout, such as features of the metabolic syndrome, chronic kidney disease and diuretic use. In patients with the onset of gout under the age of 25, with a family history of young-onset gout, or with a history of renal calculi, renal uric acid excretion should be determined to assess for urate overproduction.
Int J Clin Pract. 2010;64(3):371-377. © 2010
Cite this: Update on Gout and Hyperuricemia - Medscape - Feb 01, 2010.