Tuberculosis and HIV co-infection

Abstract 

HIV infection is the strongest risk factor for development of tuberculosis (TB) and conversely TB is the commonest HIV-associated opportunistic disease worldwide. HIV modifies the clinical presentation of TB, with an increased frequency of radiographically atypical pulmonary TB as well as extrapulmonary and disseminated disease. A high index of suspicion of TB should always be maintained during investigation of febrile HIV-infected patients and mycobacterial culture of multiple specimens is important. While it has been thought that the bacteriological response to antituberculosis treatment is not significantly affected by HIV status, some data indicate that relapse rates following standard rifampicin-containing TB treatment are higher in HIV-positive patients and may be reduced by extending therapy and by use of antiretroviral therapy (ART). Nosocomial outbreaks of multi-drug resistant TB are a risk in HIV treatment and care settings. ART reduces the incidence of TB by 80–90%, but rates nevertheless remain significantly higher than background. Concurrent administration of ART and antituberculosis drugs is complicated by pharmacokinetic interactions of rifamycins with non-nucleoside reverse transcriptase inhibitors and protease inhibitors, but good responses to ART are nevertheless achievable. The early stages of ART may be complicated by the immune reconstitution inflammatory syndrome. Here, rapid restoration host inflammatory responses to mycobacteria may lead to clinical deterioration of existing TB or ‘unmasking’ of previously subclinical TB.

Keywords: AIDS, antiretroviral treatment, HIV, immunodeficiency, immunopathology, immune reconstitution, opportunistic infection, tuberculosis