Musculoskeletal ultrasound as a tool for detecting rheumatologic manifestations in chronic hypothyroidism

Abstract

Background. Thyroid hormone regulates energy metabolism in the musculoskeletal system. Patients with hypothyroidism (HT) commonly complain of muscle and joint pain. The interaction between thyroid dysfunction and autoimmune diseases can be attributed to common autoimmune mechanisms and systemic inflammation. This observational cross-sectional study aimed to detect articular and extra-articular changes by musculoskeletal ultrasonography (MSUS), then score them using the combined OMERACT score for joints and the Madrid Sonographic Enthesitis Index (MASEI) in patients with chronic hypothyroidism to help early detection of associated autoimmune diseases. Results. MSUS revealed hypoechogenicity (MASEI-inflammatory score) as the most frequent finding, mainly in the plantar fascia, Achilles, quadriceps tendons and the common extensor tendons (CXT). Calcifications (enthesophytes) indicated by the MASEI-damage score were common in the Achilles, quadriceps, and CXT. Grade I synovitis predominated in the wrist, MCP, and knee joints, while Grade II synovitis with power Doppler (PD) positivity was seen in 21% of wrists and in 41% of knee joints (7% with PD). Paratenonitis was found in 27% of patients. OMERACT and MASEI scores correlated positively with TSH and CRP (p < 0.001) and negatively with fibromyalgia (p < 0.001), which was present in 52% of cases. Homocysteine correlated significantly with MASEI (p < 0.001). Conclusions. Musculoskeletal ultrasonography may be a helpful tool to reveal inflammatory pattern changes and coexisting rheumatologic conditions in hypothyroidism. We suggest further controlled studies for follow-up of the serial changes and MSUS findings in patients with chronic hypothyroidism.