Carpal tunnel syndrome caused by nontuberculosis mycobacteria infection

Objective To investigate the clinical features, differential diagnosis and treatment of carpal tunnel syndrome caused by nontuberculosis mycobacteria (NTM) infection. Methods Seven patients with carpal tunnel syndrome caused by NTM infection were retrospectively analyzed from June 2014 to June 2017. Carpal tunnel incision and median nerve release were performed. Synovial dysplasia was found during the operation. Samples were sent for culture and pathological examination of common bacteria, fungi and mycobacterium. The inducing factors, clinical features, differential diagnosis, culture results, treatment process and follow-up prognosis were analyzed. Results There were 3 cases with definite inducement (history of stabbing wounds such as fish and shrimp), and the other 4 cases had no definite inducement. All the patients had hand anesthesia and pain in different degrees, which manifested as acute pain in 4 cases. There were 4 cases with obvious signs of infection and 3 cases without signs of redness and swelling. Bacterial culture results: mycobacterium marinum infection in 5 cases, mycobacterium fortuitum in 1 case, mycobacterium lentiflavum in 1 case. EMG showed that median nerve carpal tunnel was compressed moderately in 5 cases and severely in 2 cases. 4 patients had a history of taking anti-mycobacterium drugs before operation. 4 cases underwent thorough debridement of the carpal tunnel, forearm and affected fingers, and 3 cases underwent median nerve release and local debridement through carpal tunnel incision. The symptoms of nerve compression, especially pain, were relieved in all the patients after the operation. 6 patients recovered after 2 to 3 months of anti-mycobacterium treatment, and 1 patient who underwent limited incision relapsed 2 months after the operation, and recovered after reoperation. Postoperative hand function recovered well in 6 cases and slightly limited in 1 case. Conclusion Carpal tunnel syndrome caused by NTM infection may be similar to idiopathic carpal tunnel syndrome, which needs to be differentiated carefully. If there is no obvious manifestation of infection, acute pain that cannot be alleviated may indicate infection. Surgery is suitable for patients with obvious symptoms of nerve entrapment that cannot be alleviated by conservative treatment. Antimycobacterium drugs are needed for 2 to 3 months after the operation. Key words: Carpal tunnel syndrome; Retrospective studies; Nontuberculosis mycobacterium; Clinical feature