The chest radiograph is utilized to screen for disease in individuals with positive PPD skin test and for those with signs and symptoms of active infection. In the past, the classic findings of tuberculosis were those associated with reactivation disease. Cavitary or noncavitary lesions in the upper lobe or superior segment of the lower lobe of the lungs are classic findings. Cavitation can be associated with increased infectivity. 4 Calcification of the lesions may be a later finding.
With the resurgence of tuberculosis, radiographic findings of primary disease are becoming more common. In primary infection, parenchymal infiltrates in any area of the lung may be found.4 Isolated ipsilateral hilar or mediastinal adenopathy is sometimes the only finding. Miliary tuberculosis as either primary or reactivation disease frequently shows small (1 to 3 mm) nodules throughout the lung fields. Pleural effusions, which are usually unilateral, can occur alone or in association with parenchymal disease. Atelectasis, fibrotic scarring, tracheal deviation, and signs of prior thoracic surgery are other findings. Because tuberculosis has a wide variety of appearances on chest radiographs, comparison to previous films is extremely helpful in determining the significance of an abnormal or unusual finding.
Immunocompromised patients, such as those with advanced HIV, are more likely to have radiographs typical of primary infection or with atypical findings. Normal radiographs in the presence of active disease are seen more frequently in HIV-infected patients. 47
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