The Role of Ultrasound in Evaluating the Effect of Urate-lowering Drugs in Gout Patients.

Abstract

Gout is one of the most common inflammatory arthritis, where identification of MSU crystals in synovial fluid is a widely used diagnostic measure. Ultrasonography has a great sensitivity in detecting signs of MSU deposits, such as tophi and double contour (DC), as mentioned in the latest gout criteria, allowing early clinical diagnosis and therapy. The objective of this study was to evaluate the changes in ultrasound of gout patients' knee and 1st metatarsophalangeal joint (MTP1) after initiation of urate-lowering therapy (ULT) drugs in the six-month period. Forty-three patients, fulfilling the ACR/EULAR 2015 criteria of gout with a score of >8, were enrolled; they were in between attacks and not on ULT for the last 6 months, or SUA concentration (SUA) of >6.0 mg/dL. Full examination, evaluation of joints pain by visual analog scale (VAS), ultrasonography (US) for tophus and DC at the knee, and MTP1 were performed at baseline and at 3 and 6 months (M3, M6) after starting ULT. After 6 months of treatment, patients reached the target SUA level showed higher disappearance of DC sign (p<0.05) and a decrease in tophus size (p<0.05). The percentage of tophus size at 6th month was 26.4% and 3% for DC sign disappearance, which was more at MTP1. Ultrasound examination in screening for gout tophi or DC sign before starting ULT and during follow-up is important and complements clinical examination.