Tuberculous is the leading cause of death for people with HIV, accounting for about 360,000 deaths in 2013.
Untreated HIV infection markedly increases the risk of TB, which remains the most common cause of hospitalization and death globally among patients with HIV infection in the era of anti-retroviral therapy.
Fatalities are significantly higher in individuals with tuberculosis plus HIV co-infection because of increased disseminated extra-pulmonary tuberculosis, and more severe forms of disease associated with progressive immunosuppression.
Tuberculosis is the cause of death in nearly 40% of HIV-positive patients most having disseminated disease (85%) and nearly half remaining undiagnosed at the time of death.
The relative risk of TB among HIV infection increases exponentially as CD4+ T-lymphocyte counts decline.
The risk of incurring TB in HIV is increased by a factor of more than 25 when the CD4 positive T-lymphocyte count is less than 200 per microliter as compared with the count of 1000 per microliter.
Tuberculosis and HIV co-infection patients are often unable to expectorate, or have extra-pulmonary disease, needing sputum induction or alternative invasive sampling to acquire material for diagnosing tuberculosis.
Patients with tuberculosis and HIV co-infection with advanced immunosuppression often have low bacillary loads and other body fluids thus reducing the sensitivity of traditional diagnostic tests and nucleic acid amplification based diagnostics.
The use of anti-retro viral therapy has reduced the incidence of tuberculosis among people with HIV infection by 67 to 84%.
WHO estimated that tuberculosis developed in 10.6 million people in 2021, and 6.7% of those patients were HIV positive.
In 2021 11.8% of tuberculosis deaths globally was accounted for by an association with HIV.
Tuberculosis related mortality is higher among patients with HIV due to the more rapid immunosuppression progression and tuberculosis is more difficult to diagnose in patients with HIV.
CD4 positive T-lymphocytes produce interferon gamma, which activates macrophages infected with tuberculosis and facilitates intracellular killing: the progressive CD4 positive T lymphocyte depletion occurs with untreated HIV infection.
Macrophage activation has a key role in granuloma formation, which is critical for limiting the growth and spread of M. Tuberculosis.
T-lymphocyte depletion has multiple alterations in immune functions, which result in increased mycobacteria activity, by impairing macrophage phagocytosis, apoptosis , dendritic cell processing and antigen presentation, and neutrophil microbial killing capacity.
TB skin test and interferon gamma release essays reflect the presence of an adaptive memory response to mycobacterial antigens and these tests are used in the diagnosis of tuberculosis infection.
These tests may be negative and people would advance HIV infection.
The Alere Determine tuberculous lipoarabinomannan Ag lateral flow strip test is a commercially available bedside tuberculosis diagnostic test providing a result within 25 minutes, using 60 mL of urine to detect lipoarabinomannan, a glycolipid antigen of the M tuberculosis cell wall.
Drug-drug interactions and immune reconstitution complicate cotreatment of TB and HIV infection.