Diagnosis is the proper classification of an individual patient. Efforts to develop clinical criteria for the classification of gout, which are often used to diagnose individual patients, continue, as the article by Prowse, et al shows in this issue of The Journal1. A proper approach to gout diagnosis implies that, if possible, (1) all patients presenting with the disease have to be properly diagnosed, and (2) in all cases the diagnosis must be correct, so gout does not go undetected and is not misclassified.
Gout results from monosodium urate (MSU) crystal deposition, which is responsible for all clinical consequences of the disease. MSU crystals are large enough to be easily detected and identified by an ordinary microscope fitted with polarized filters, which clearly shows the highly birefringent MSU crystals shining on the dark microscope field. The addition of a first-order red compensator helps in definitive distinction from calcium pyrophosphate (CPP) and other crystals2. Crystals form as a result of elevated serum uric acid (SUA) levels; they slowly dissolve and finally disappear when SUA levels are brought back to normal; thus, the disease is now considered curable3. Because it is associated with an elevated cardiovascular risk4 and, when advanced, can be very disabling, gout cannot be taken as a minor disease. MSU crystals are regularly present in synovial fluid …
Address correspondence to Prof. E. Pascual, Rheumatology Section, Hospital General Universitario, Maestro Alonso 109, Alicante, 03010, Spain. E-mail: pascual_eli{at}gva.es