These OIs result in more rapid decline in CD4 T-cell count than the decline resulting from HIV disease itself. Thus effective therapy is required to treat and prevent these infection. The incidence and type of OIs in HIV patients is directly related to the CD4 count in that individual. Common OIs are Tuberculosis both pulmonary and extra-pulmonary , Oropharyngeal candidiasis, Herpes zoster, Herpes simplex, Toxoplasmosis, Cryptococcal Meningitis, Pneumocystitis carini pneumonia, Cytomegalovirus retinitis, Cryptosporidial diarrhea. It ranks one of the most common opportunistic infections.
Clinical presentation is usually similar to that in non-HIV patients.
Typical symptoms include productive cough of several week's duration, fever, weight loss, night sweats and haemoptysis. In patients with advanced HIV disease extra-pulmonary disease is more common. Disseminated disease with involvement of bone marrow, bone, urinary and gastrointestinal tract, liver, regional lymph nodes, and central nervous system is common. Tuberculosis in HIV patients may show atypical findings in the chest x-ray, negative tuberculin reaction, and extra pulmonary lesions. Management of HIV related tuberculosis is complicated as there is significant interaction between antiretroviral therapy and standard anti-TB medication.