An exploratory ultrasound study of early gout

We aimed to determine by ultrasonography (US) the prevalence of articular monosodium urate deposits in patients with gout who do not require urate lowering therapy (ULT) according to international recommendations.

In this prospective study, we enrolled patients with proven gout demonstrated by crystals in synovial fluid but who did not require ULT. Two trained ultrasonographers assessed 10 joints per patient (metatarsophalangeal [MTP] joints 1-2, knees, metacarpophalangeal [MCP] joints 2-3) to determine the prevalence of the double-contour (DC) sign and tophi in each site.

We studied 150 joints from 15 patients (median age 56.9 years [interquartile range 31.7] years; 14 males). The median number of acute attacks per patient was 2.0 [0.7]. Interobserver agreement was good to excellent for all articular sites. The prevalence of the DC sign in the knees and MTP joints was 46.7% and 40% respectively, whereas that of tophi was 26.7% for both sites. No urate deposits were found in MCP joints. The DC sign and tophi were found in at least one articular site in 60% and 46.7% of patients, respectively. All patients with urate levels > 600 μM (10 mg/dl) had a DC sign in at least 1 assessed joint. Urate levels were positively correlated with presence of the DC sign in knees (p=0.005) and MTP joints (p=0.03) but not presence of tophi.

In this study, ultrasonography allowed for detecting articular urate deposits in 60% of gouty patients not requiring ULT by international recommendations.