Patients with an abnormal chest radiograph and latent tuberculosis.

Patients with latent tuberculosis characterized by a positive tuberculin (purified protein derivative) skin test and radiographic evidence of fibronodular changes or silicosis are at increased risk for the development of active tuberculosis. Before preventive therapy is initiated, the radiographic abnormalities must be differentiated from those representing active disease. According to recommendations from the American Thoracic Society and the Centers for Disease Control and Prevention, patients with latent tuberculosis who exhibit fibronodular changes or silicosis on chest radiographs should be given either isoniazid alone for one year or the combination of isoniazid and rifampin for four months, preferably with pyrazinamide for the first two months. Patients with similar radiographic findings and sputum or culture evidence of active tuberculosis require full multidrug therapy.