Extrapulmonary tuberculosis in a high incidence area requiring enhanced infection prevention procedures

Background: According to the CDC, persons with extrapulmonary tuberculosis (EPTB) are not infectious unless they have concomitant pulmonary, oral or layngeal disease, or open draining lesion with high concentration of organisms, or if aerosolization of drainage fluid occurs. Patients with possible EPTB requiring a diagnostic surgical procedure require special infection prevention considerations, as well as early recognition of infectious status. Although several studies have reported on nosocomial transmission of Mycobacterium tuberculosis (Mtb) associated with EPTB, current infection prevention recommendations emphasize the risk of transmission of Mtb of pulmonary disease. Healthcare personnel awareness about the risk of Mtb transmission by patients with EPTB appears to be generally low.

Objective: To describe the epidemiological and clinical characteristics of patients with EPTB, and the implementation of infection prevention procedures during their care in a medical center serving an area with high tuberculosis (TB) incidence.

Methods: A retrospective study of patients diagnosed with EPTB in Regional Medical Center of San Jose, a 247-bed trauma medical center serving Santa Clara County, CA, from January, 2005, until July, 2010, was performed. Patients were identified by microbiology results from surgical biopsy and sputum cultures. Epidemiologic and isolation precaution procedures were analyzed.

Results: A total of 117 cases of culture-positive TB were identified. Compared to national data, our medical center had a relatively high percentage of EPTB cases, 31% (36 cases). Lymphatic (67%) and pleural (14%) disease were the most common manifestations of EPTB. Less common sites of EPTB included colon, bone, urine, spinal fluid and pancreas. Although all cases of pulmonary TB were placed under appropriate isolation precautions, a minority of EPTB cases had concurrent pulmonary TB and were placed in airborne isolation. Most cases of EPTB had negative acid fast bacilli (AFB) stains of biopsy tissue, and were associated with delayed diagnosis until respective cultures became positive for Mtb. There were no documented TB skin conversions among healthcare personnel during the study period. As a result of this study, an educational program, aimed at raising awareness of the potential infectiousness of EPTB, and enhanced infection prevention procedures were implemented.

Conclusions: A relatively high number of patients with EPTB who underwent hospital-based surgical procedures were identified leading to an educational campaign, aimed at increasing awareness among healthcare personnel of the potential infectiousness of EPTB, and implementation of appropriated infection prevention procedures. Our study underscores the importance of early identification and triage of patients with infectious EPTB who undergo hospital-based surgical procedures.