Comparison of the ultrasonic difference between gouty arthritis with chronic kidney disease and simple gouty arthritis

Objective To compare the ultrasound differences between gouty arthritis with chronic kidney disease(GCKD) and simple gouty arthritis(GA), and evaluate the correlation between the number of tophi and the degree of renal impairment. Methods Twenty-two patients with GCKD and 22 patients only with GA were examined by high frequency and color Doppler ultrasound. The differences between the tophus, intra-tendinous aggregate, double contour sign, hyperechoic spots in synovium, synovium hyperplasia, effusion and erosion of the knee, ankle and first metatarsophalangeal joint(MTP1) were examined. The correlation between the degree of renal impairment and the number of tophi was analyzed. Results The prevalence of tophi in GCKD group were significant serious compared with simple GA group (Z=-3.915, P<0.001). The articulations involved tophi in GCKD group were more than those in simple GA group(χ2=20.283, P<0.001). And the tophi in GCKD group were more likely to involve multiple articulations while simple GA group frequently manifested none or single articulation involved(χ2=13.165, P=0.001). The tophus in GCKD group was more frequently involved tendon than that in simple GA group (χ2=6.783, P=0.009), but the number of aggregates in tendon showed no significant difference between the two groups (Z=-1.499, P=0.134). The double contour sign was more frequent in GCKD group than that in simple GA group(χ2=7.511, P=0.006), there was no difference of hyperechoic spots in synovium, synovium hyperplasia, effusion and erosion between the two groups. The number of tophi was correlated with estimated glomerular filtration rate (eGFR), serum creatinine(SCr) and blood urea nitrogen(BUN) (rs=-0.595, 0.511, 0.583; all P<0.001), respectively. Conclusions GCKD is more likely to manifest multiple tophi, multiple tophus-involved articulations, intra-tendinous tophi and double contour sign. The number of tophi is correlated with the degree of renal impairment. Key words: Ultrasonography; Gout; Arthritis; Chronic kidney disease