TB-HIV co-infection: a catastrophic comradeship

The symbiotic association of tuberculosis (TB) and HIV poses a challenge to human survival. HIV complicates every aspect of TB including presentation, diagnosis and treatment. HIV-TB patients encounter unique problems like drug-drug interactions, cumulative toxicity, immune reconstitution inflammatory syndrome (IRIS), lower plasma drug levels and emergence of drug resistance during treatment despite adherence. TB may also be overdiagnosed in HIV due to a number of diseases that closely resemble TB. Notable among them are non-tuberculous mycobacteria, Pneumocystis Jirovecii and Nocardia. Even though diagnostic procedures have improved over the years, patients in developing countries usually seek health care at later stage of the disease. Research data ascertains the duration of therapy for TB to be 6 months with rifampicin and isoniazid, reinforced with ethambutol and pyrazinamide in the first 2 months. The schedule of therapy is still debatable with daily regimens being preferred in the context of HIV. Many reasons exist for persistence of Mycobacterium Tuberculosis (M.TB) in sputum, or delayed-clearance of TB from sputum smears in HIV, apart from emergence of drug resistance and non-compliance. Acquired rifampicin resistance (ARR) is a unique phenomenon complicating HIV-associated TB when an intermittent regimen of antituberculosis therapy (ATT) is used without timely initiation of highly active antiretroviral therapy (HAART), especially in patients harbouring isoniazid-resistant strains Immune restoration is often incomplete ('swiss cheese' pattern) even with effective HAART if not started early. Immune reconstitution inflammatory syndrome (IRIS) is the paradoxical worsening of the patient's condition often with radiological deterioration, due to an enhanced immune response with HAART. IRIS occurs despite an effective virological suppression and a favourable response to ATT. The incidence of IRIS in HIV has reached up to 54%, requiring utilization of experts and tertiary care which forms an obstacle to the decentralization of patients in the ART programme. Research in HIV-TB immunology and management needs further exploration in order to understand the diseases and offer appropriate treatment. The following paragraphs provide scientific evidences generated through research that could potentially guide management.