and peritoneal cavity (1%) (CDC 2005c). Disseminated extrapulmonary TB, known as miliary TB, consists of 1-3 mm nodules throughout the lungs and other tissues.
Primary TB is sometimes manifested as an infection of the pleural space, and TB pleurisy may develop later as a progression of LTBI to pleural TB with or without pulmonary TB. The typical presentation is acute onset of fever, cough, and pleuritic chest pains, although there may be a chronic course characterized by fever, general malaise, and loss of up to 10% of body weight. The pleural effusions usually are small to moderate. Concurrent parenchymal disease occurs in one-third to one-half of cases. Diagnosing TB pleurisy usually requires a pleural biopsy, which has a diagnostic yield of 85-95%. The initial TST is negative one-third of the time. Although pleural fluid is exudative, it usually tests negative with an AFB smear and, in 75% of cases, in cultures.
The committee concludes that there is sufficient evidence of a causal relationship between infection with Mycobacterium tuberculosis and occurrence of active tuberculosis months to decades after infection.
HIV alters the clinical manifestations of TB. For example, pulmonary TB may occur in a lower lobe in a noncavitary fashion. There may be hilar or mediastinal adenopathy, pleural disease, or a normal chest x-ray picture. Extrapulmonary TB is more common among patients coinfected with HIV than among other patients, and it may occur with pulmonary disease or alone. The interactions between chemotherapeutic drugs for TB with antiretroviral drugs for HIV challenge the clinician to treat TB-HIV coinfections effectively.
Treatment for drug-sensitive active TB consists of isoniazid, rifampin, pyrazinamide, and ethambutol for 2 months followed by isoniazid and rifampin for 4 months. That regimen is 95% effective, although about 5% of patients will experience relapses of active TB, most of them in the first 1-2 years after treatment completion (CDC 2003a).
Multiple-drug-resistant TB is more difficult to cure. Regimens should be tailored to known drug susceptibility of the isolates. If an isolate is resistant to isoniazid and rifampin but susceptible to other drugs, treatment regimens would consist of ethambutol, pyrazinamide, and levofloxacin for 12-18 months and an injectible aminoglycoside for the first 2-3 months.
Even after highly effective treatment for acute TB, affected tissues and organs may be functionally impaired or destroyed. Functional impairment may range from imperceptible to severe. The paucity of data on long-term health outcomes of acute TB and the ability of M. tuberculosis to infect and damage virtually any organ of the body challenged the committee to address the late manifestations of this disease comprehensively. This discussion addresses the notable late manifestations of acute TB and the committee’s conclusions about the strength of the association between acute and long-term adverse health outcomes.