Background Carpal Tunnel Syndrome (CTS) is a relatively frequent condition in rheumatoid arthritis (RA), but we should be aware of the connection between carpal tunnel syndrome (CTS) and hypothyroidism.The carpal tunnel is the fibroosseous space between the carpal bones and the flexor retinaculum. It contains 8 flexor tendons, the flexor pollicis longus tendon and occasionally a persistent median artery. CTS is the result of compression of the median nerve within this contained space.
Objectives The objectives of the study were to assess the outcome of ultrasound guided cortisone injection in patients with rheumatoid arthritis and hypothyroidism.
Methods The study included 35 patients – 25 with known rheumatoid arthritis and 10 with hypothyroidism who received a local corticosteroid injection for carpal tunnel syndrome. All patients underwent a bilateral carpal tunnel US examination. The CSA (cross-sectional area) of the median nerve was measured at the carpal tunnel and at the level of the pronator quadratus muscle, and the difference between them (ΔCSA) was calculated for each wrist. All carpal tunnel syndromes were diagnosed usingof a ΔCSA threshold of 2 mm2 rule.
Results After 1 month, most patients improved, but after 12 months 23 patients (65.71%) – 20 with rheumatoid arthritis and 3 with hypothyroidism, had surgery. Patients with a successful outcome (no need for additional treatment) had a lower median nerve ultrasonographic cross-sectional area (CSA) at the flexor retinacullum, a lower swelling ratio, and a lower symptom severity score (VAS). Most of the patients with hypothyroidism improved after injection and hormone replacement therapy.
Conclusions Lower swelling ratio measured by ultrasonography may indicate a less severe carpal tunnel syndrome, which is more likely to respond to treatment with a corticosteroid injection. More than this, patients with hypothyroidism are more likely to have a better outcome without surgery.
Disclosure of Interest None Declared