Nontuberculous Mycobacterial Infections of the Upper Extremity: 15-Year Experience at a Tertiary Care Medical Center.

PURPOSE: To present our experience with culture-positive, nontuberculous mycobacterial infections (NTMI) of the upper extremity and to compare the clinical features and outcomes of treatment among immunocompetent and immunocompromised patients.

METHODS: All patients at our medical center diagnosed with NTMI of the upper extremity from December 1, 2000, through December 31, 2015, were included. We performed a retrospective analysis of patient demographic characteristics, delay to diagnosis, risk factors, clinical presentation, specific location, diagnostic testing, treatment regimens, and outcomes. These variables were compared between immunocompetent and immunocompromised patients.

RESULTS: Forty-four patients were identified with culture-positive NTMI of the upper extremity. Of the patients, 27 (61%) were men (median age, 59 years [range, 23-83 years]). Twenty (45%) patients were immunocompromised. Immunocompromised patients had fewer known inoculation injuries compared with immunocompetent patients (45% vs 92%). A significant difference existed in the treatment regimens selected for immunocompetent versus immunocompromised patients: immunocompetent patients were more often treated with both antibiotics and surgery (88% vs 50%), whereas immunocompromised patients were more often treated with antibiotics alone (45% vs 4%). Overall, 24% experienced treatment failure and 9% died. Outcomes were relatively similar between immunocompetent and immunocompromised patients. A shorter delay to diagnosis was associated with a lower failure rate.

CONCLUSIONS: Diagnosis of upper-extremity NTMI is often delayed because of indolent presentation and lack of clinical suspicion. The clinical presentation, diagnostic delay, and diagnostic testing results are similar between immunocompetent and immunocompromised patients. Although treatment varied significantly between patient groups, outcomes were similar. Timely diagnosis has the greatest impact on patient outcome.

TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic IV.