The lifetime risk of developing active TB in subjects with latent tuberculosis infection without the human immunodeficiency infection (HIV) co-infection is 5-10%; for people living with HIV (PLWHIV), the annual risk is 3-16% per year.
The interaction of these two pathogens is complex: HIV-1 co-infection is the most significant risk factor for developing active tuberculosis, while M. tuberculosis coinfection leads to increased viral replication and disease progression.
Clinical presentation will vary depending on the degree of immunodeficiency. Patients with higher CD4 cell counts can present with the classic symptoms, while the clinical presentation of TB in patients with advanced immunodeficiency (less than 200 cells/mm3) is usually atypical. Extrapulmonary tuberculosis is more frequent among co-infected individuals regardless of the CD4 cell counts, occurring in up to 70% of patients with CD4 counts of ≤100 and about 30% of subjects with counts of >300 cells/mm3.
The diagnostic approach in subjects with TB-HIV-1 co-infection is the same as that of patients without HIV infection, with the goal being the microbiologic confirmation of the diagnosis.
Antiretroviral (ART) should be started in all TB patients living with HIV regardless of their CD4 cell count. Antituberculosis treatment should be initiated first, followed by ART as soon as possible within the first 8 weeks of treatment. Unfortunately, the restoration of the immune response sometimes has an undesirable effect known as immune reconstitution inflammatory syndrome (IRIS).