Establishing the Diagnosis
Aspiration of synovial fluid or tophi from an actively inflamed joint and the identification of monosodium urate (MSU) crystals through a polarizing microscope remains the gold standard for making an accurate diagnosis of gout. However, physicians and other health care providers rarely make a diagnosis this way, given the need for specialized equipment and training. Most physicians must make a probable diagnosis based on how closely the patient’s history and examination aligns with the classic description of gout symptoms.
Presumed gout is a diagnosis based on a pattern of recurrent, rapid onset flares of monoarthritis in the historical setting of hyperuricemia. A clear and detailed history of an acute gout flare, followed by an asymptomatic period and then recurrence, is a valuable pattern for recognition and diagnosis. While diagnosing gout based on typical features of gout and documented hyperuricemia is common, it is flawed. And, while the risk for developing gout is higher in those who have an elevated serum uric acid level and joint pain, not everyone with these factors has gout.
Additional Methods for Detecting Gout
Use of diagnostic ultrasound is coming into common use, and may help to improve early diagnostic accuracy. MRIs and CT scans can also be very useful, but are rarely used at the point of care. Visible tophi and erosive changes can also be visible on x-rays, but these are typically late findings after gouty arthritis has already progressed.