Tuberculosis of the wrist causing carpal tunnel syndrome in a patient with rheumatoid arthritis: A case report.

Among extrapulmonary tuberculosis, osteoarticular tuberculosis is a rare manifestation, and cases related to osteoarticular tuberculosis of large joints have been reported previously. However, tuberculous tenosynovitis causing carpal tunnel syndrome is a rare manifestation, especially in the background of rheumatoid arthritis. A 67-year-old Sri Lankan male with a background of rheumatoid arthritis presented with progressively enlarging left wrist swelling associated with pain and numbness for 2 months. He was on Methotrexate and Hydroxychloroquine as disease-modifying agents, and his symptoms related to arthritis were well controlled. On examination, lobulated subcutaneous swelling was noted in distal forearm extending to the palmar region with evidence of carpal tunnel syndrome which was confirmed by nerve conduction studies. There was no pre-operative evidence to suggest tuberculosis both clinically and biochemically. Synovial thickening due to rheumatoid arthritis was considered as the probable diagnosis and surgical decompression of the carpal tunnel was performed. Intraoperatively, synovial thickening was noted around the flexor tendons with evidence of median nerve compression in the carpal tunnel. Thickened synovial mass was completely excised. Histology and culture were positive for tuberculosis. Following excision and 9 months of anti-tuberculosis treatment, he was asymptomatic with good range of motion of fingers. In conclusion, a combination of surgical excision and anti-tuberculosis treatment was successful to achieve good functional outcomes. In a country like Sri Lanka, where tuberculosis is still prevalent, uncommon musculoskeletal manifestations may not be infrequent. Therefore, clinicians should have a high degree of suspicion when treating such patients.