Prevalence of carpal tunnel syndrome in patients with rheumatoid arthritis by ultrasonographic and electrodiagnostic studies

Introduction Rheumatoid arthritis (RA) is an autoimmune disease characterized by articular and extra-articular structures. Carpal tunnel syndrome (CTS) is one of the most frequent extra-articular manifestations of RA. Aim To detect the prevalence of CTS in patients with RA and the accuracy of ultrasonography (US) in comparison with nerve conduction study (NCS). Patients and methods This was a case–control study carried out at Al-Zahraa University Hospital. It was conducted on 50 patients with RA and 30 controls. They were evaluated by history taking, clinical evaluation, assessment of RA disease activity by disease activity score 28, disability by Health Assessment Questionnaire, functional status by the Boston Questionnaire, bilateral median (MN) NCS, and US, which was used for cross-sectional area and flat ratio of the median nerve at different levels of carpal tunnel and examination of other carpal tunnel contents. Results CTS was diagnosed in 27% of the patients with RA by US and 20% by NCS. There was a highly significant difference between the patients with RA and control groups regarding cross-sectional area and flat ratio of the transverse scan of the MN at three different levels (P<0.07 and 0.001). There was a positive relation between the outcome of US and the NCS in the diagnosis of CTS in patients with RA (P<0.001). Conclusion US has the advantage of early detection of CTS and can assess the morphology of MN and its surroundings.