Background: Co-infection with Mycobacterium tuberculosis and M. leprae is infrequent and conflicting views on their interaction exist.
Methods: We describe an immunocompetent male with simultaneously diagnosed primary multi-drug resistant extra-pulmonary tuberculosis and borderline lepromatous leprosy; we also review all cases of dual infection reported in English literature
Results: Our search yielded 156 cases of dual infections. Most dual infections were reported in middle-aged males. The sentinel infection was leprosy in 90.4%. Most affected patients had lepromatous leprosy (52.5%) but tuberculosis occurred throughout the disease spectrum of leprosy. The time to development of the second infection varied from 1 month-25 years (median 1.5 years). Tuberculosis was reported to occur in 2.5-13.5% of cases in six series of patients with lepromatous leprosy. Most patients were diagnosed by sputum smears and radiography. Comorbid conditions predisposed to development of tuberculosis in most patients. The most common pre-disposing factor was malnutrition (92.5%). Dual infections were associated with high mortality (37.2%) and morbidity (5.3%)
Conclusions: Dual mycobacterial infections occur despite partial cross-immunity between both species. Directly observed treatment for tuberculosis with intensive medical monitoring is required to prevent poor outcomes during management of these complex patients