Urate crystal deposition in asymptomatic hyperuricaemia and symptomatic gout: a dual energy CT study

TLDR

The study compares dual‑energy CT urate deposit frequency and volume between asymptomatic hyperuricaemic and symptomatic gout patients. DECT foot scans were analyzed in 25 asymptomatic hyperuricaemic and 33 gout patients without tophi. DECT detected urate deposits in 24 % of asymptomatic hyperuricaemic, 79 % of early gout, and 84 % of late gout patients, with lower frequency and volume in the asymptomatic group and similar volumes between early and late gout, implying a volume threshold for symptom onset.

Abstract

<h3>Background</h3> The aim of this study was to compare the frequency and volume of dual energy CT (DECT) urate deposits in people with asymptomatic hyperuricaemia and symptomatic gout. <h3>Methods</h3> We analysed DECT scans of the feet from asymptomatic individuals with serum urate ≥540 µmol/L (n=25) and those with crystal proven gout without clinically apparent tophi (n=33). <h3>Results</h3> DECT urate deposits were observed in 6/25 (24%) participants with asymptomatic hyperuricaemia, 11/14 (79%) with early gout (predefined as disease duration ≤3 years) and 16/19 (84%) with late gout (p&lt;0.001). DECT urate deposition was observed in both joints and tendons in the asymptomatic hyperuricaemia group, but significantly less frequently than in those with gout (p≤0.001 for both joint and tendon sites). The volume of urate deposition was also significantly lower in those with asymptomatic hyperuricaemia, compared with the early and the late gout groups (p&lt;0.01 for both comparisons). Similar urate volumes were observed in the early and late gout groups. <h3>Conclusions</h3> Although subclinical urate deposition can occur in people with asymptomatic hyperuricaemia, these deposits occur more frequently and at higher volumes in those with symptomatic gout. These data suggest that a threshold of urate crystal volume may be required before symptomatic disease occurs.