Ultrasonographic Features of Lower-Limb Joints in Gout

Which Joints and Clinical Characteristics Would Provide More Information for Diagnosis?

Weijing Zhang, MD; Zhibin Jin, MD; Wenjing Xiang, MD; Min Wu, MD; Shiying Wang, PhD; Huayong Zhang, PhD; Pingyang Zhang, PhD

Disclosures

J Clin Rheumatol. 2020;26(1):14-18. 

In This Article

Abstract and Introduction

Abstract

Objective: This observational cross-sectional study evaluated the distribution of ultrasound (US) features of lower-limb joints and the risk factors of tophus in gout patients.

Methods: We examined 588 joints including the bilateral knee, ankle, and first metatarsophalangeal (MTP) joints in 98 gout patients by US between March to August in 2017. The distribution of double-contour (DC), tophus, aggregates, synovitis, effusion and erosion in different joint, course, and age groups were investigated by Cochran Q and χ2 test. The risk factors of tophus were analyzed using logistic regression method.

Results: Double-contour was most commonly observed in the knee (p = 0.005). Tophus, aggregates, synovitis, and erosion were mostly detected in the first MTP (p < 0.001, p = 0.01, p = 0.001, p < 0.001, respectively). The prevalence rates of DC, tophus, and erosion in patients with a longer course were significantly higher (p = 0.029, p = 0.002, p < 0.001, respectively). Older patients had more detectable tophus and erosion than younger patients (p = 0.028, p = 0.021). Patients of older age (odds ratio [OR], 3.83; 95% confidence interval [CI], 1.27–11.48), with frequent attacks (OR, 3.80; 95% CI, 1.10–13.15), and with longer course (OR, 6.52; 95% CI, 1.37–30.96) had higher risks of tophus.

Conclusions: Most signs were detected by US in the first MTP, except that DC was most commonly observed in the knees. Patients of older age with frequent attacks and longer course may experience higher risks for tophus. Comprehensive assessment of the lower limbs, particularly the knee and first MTP, can significantly help diagnosis.

Introduction

Gout, the most common inflammatory arthritis in men, is mainly induced by the deposition of monosodium urate crystals on joints and surrounding tissues. In recent years, with rapid economic development, the prevalence of gout has risen significantly in China, which has become a social problem.[1–3] Early diagnosis of gout and lifelong urate-lowering therapy (ULT) are highly recommended for patients with gouty arthritis.[4]

High-resolution ultrasound (US) is a noninvasive, simple, and cost-effective method, which is suitable for large-scale routine screening and long-term follow-up in nations with a huge population base such as China. Previous studies confirmed the diagnostic value of US.[5–8] However, most of these studies observed only clinically affected joints that did not comprehensively depict the joint condition. In fact, the uninvolved joints, at the time of the assessment, may also have had some positive signs that were helpful for diagnosis, and a consensus regarding which joint should be examined has not been reached.[9] In addition, different stages of the disease as well as individual diversity led to complex and various manifestations of the ultrasonographic images, which increased the difficulty in diagnosing gout.[10] Knowing about the relationship between biological or demographic characteristics and US findings can further improve awareness concerning gouty arthritis, which can help physicians to make early clinical diagnosis and perform intervention as soon as possible.

The aim of this study was to identify specific and nonspecific US features of different parts of the lower limbs and to evaluate predictive clinical factors for the formation of tophi.

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