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Tuberculosis in HIV infected patients

Active tuberculosis in HIV-positive patients represents both reactivation of latent infection and primary disease. HIV increases the chance of reactivating dormant tuberculosis infection from 5-10 percent over a person's lifetime to 7-10 percent per year.

TB is one of the earliest occurring HIV-associated infections. TB progresses at an accelerated pace in HIV-infected patients, and TB infection may act.

Clinical Evaluation

The diagnosis of TB should be considered in all HIV-infected persons. In patients with low CD4 cell counts, TB presents with atypical pulmonary manifestations and extrapulmonary disease.

Symptoms of Active Pulmonary Tuberculosis. Cough, hemoptysis, fever, night sweats, weight loss, shortness of breath, and chest pain.

Assessment of Tuberculosis Risk Factors

Previous tuberculosis infection or disease, or past treatment or history of exposure to tuberculosis should be sought.

A history of foreign country of origin, homelessness, prison, or congregate living should be assessed.

Patients suspected of having active disease should receive a chest X-ray and smears and cultures of sputum. The inability to demonstrate acid-fast bacilli does not completely exclude TB.

Culture techniques may detect mycobacteria in 10-14 days. The acid-fast bacilli smear of sputum can detect mycobacteria within hours. Rapid diagnostic tests can be used for patients with tuberculosis, HIV, AIDS positive AFB smear sputum.

Patients suspected of having extra-pulmonary disease (unexplained fevers and night sweats) require evaluation with more invasive tests such as a spinal tap or biopsy of lymph nodes, liver or bone marrow.

Blood cultures for AFB are positive in up to 25-50% of patients with HIV disease and TB.

Treatment tuberculosis, HIV, AIDS for Active Tuberculosis

Treatment should be initiated at the time the disease is considered a reasonable possibility (positive sputum AFB smear), while cultures are pending. Respiratory isolation should be initiated if the patient is coughing.

Patients should be started on a 4-drug regimen consisting of isoniazid, rifampin, pyrazinamide, and either ethambutol or streptomycin. In areas with multi-drug resistant strains, consideration should be given to using all five drugs and perhaps adding a quinolone. After susceptibility results are known, the treatment regimen can be modified.

Four-drug Regimen

Isoniazid, 300 mg PO qd

Rifampin, 600 mg PO qd

Pyrazinamide, 25 mg/kg PO qd

Ethambutol, 15 mg/kg PO qd, max 2.5 g/d or Streptomycin 15 mg/kg IM qd.

Patients with pan-susceptible organisms are treated for 6-9 months, with only isoniazid and rifampin continued after the first two months.

Treatment is continued for at least three months after the last negative sputum culture. Treatment should be continued for a total of 9-12 months if there is any evidence of non-compliance or a slow bacteriologic response. Directly observed therapy (DOT) lowers rates of drug resistance, and it should be administered for all patients.

If DOT is not available, combination tablets should be used. Rifamate is a combination tablet that contains rifampin 300 mg, isoniazid 150 mg; 2 cap qd. Rifater contains isoniazid 50 mg/rifampin 120 mg/pyrazinamide 300 mg; 6 tablets qd.

Clinical Follow-up. Response to therapy is signified by resolution of fever, cough, sputum production, and hemoptysis. Bacteriologic response is monitored by repeat sputum exams and cultures for AFB. Most patients are culture-negative by 3 months. If sputum smears remain persistently positive, non-compliance should be suspected and supervised daily therapy considered. If non-compliance is unlikely, then drug resistance should be considered.

Screening for Latent Tuberculosis