Temporal evolution of urate crystal deposition over articular cartilage after successful urate-lowering therapy in patients with gout: An ultrasonographic perspective

Abstract

Objective: To detect evolution of ultrasonographic signs of deposition of monosodium urate crystals (MSUC) in gouty joints by serial ultrasonography after initiation of urate-lowering therapy (ULT).

Methods: Adult gout patients were examined by serial ultrasonography after initiation of ULT with target serum uric acid (SUA) < 6 mg/dL.

Results: Thirty-eight male patients with gout with mean age of 50 ± 11 years, median disease duration of 48 months and baseline mean SUA level of 8.8 ± 1.5 mg/dL were recruited. Ultrasonographic evidence of MSUC deposition was detected in 89.74% of first metatarsophalangeal (MTP) joints and 27.63% of knee joints. Double contour sign (DCS), tophi, and hyperechoic spots (HES) were detected in 77.63%, 43.42%, and 19.74% of first MTPs, respectively. SUA level normalizes and plateaus after fourth month of follow-up. DCS thickness reduced significantly throughout the follow-up period. Overall, 86.25% DCS and 100% HES disappeared with median time of 6 months and 5.7 months, respectively. SUA normalization was the only significant predictor of DCS disappearance.

Conclusions: Serial ultrasonographic determination of DCS, tophi, or HES during hypouricemic therapy is a noninvasive, effective method to detect the lowering of burden of urate load in gouty joints.

Keywords:

• Double contour sign
• Gout
• Serial ultrasonography
• Ultrasonography
• Urate crystal

Acknowledgments

The authors wish to thank Dr. Debashish Danda, Professor and Head, Department of Clinical immunology and Rheumatology, Christian Medical College, Vellore, Tamil Nadu, India for his valuable advice at the inception of this study. The authors also wish to express their gratitude to Dr. Subhankar Haldar, Dr. Anupam Maity, and Dr. Arghya Chattopadhyay of Institute of Postgraduate Medical Education and Research, Kolkata (IPGME&R) for patient recruitment and Dr. Sumantro Mondal of IPGME&R for radiological assistance.

Conflict of interest

The authors report no conflicts of interest. The authors alone are responsible for the content and writing of this article.