A 5-year-old child is exposed to Mycobacterium tuberculosis. A month later the child's tuberculin skin test is positive. The child then develops fever, inspiratory stridor, and nonproductive cough. Which of the following findings is most likely to be present on the chest radiograph of this child?

The child has a primary tuberculosis. Most healthy persons have a sub-clinical disease, and a minority develop clinical manifestations; of those, most have limited pulmonary involvement without dissemination. Primary tuberculosis is marked by the Ghon complex, which is a small subpleural granuloma at mid-lung along with prominent enlarged hilar lymph nodes. These nodes may impinge upon central airways. When the cell-mediated immune response is poor, then there can be numerous small granulomas scattered throughout the lungs, or disseminated to other organs, as a miliary pattern (granulomas that are the size of millet seeds). Progressive primary tuberculosis can lead to more extensive lung involvement with pneumonic infiltrates. Upper lobe cavitary disease is characteristic of secondary tuberculosis (reactivation or reinfection) in persons who have previously mounted an immune response. One pattern of disseminated tuberculosis is Pott disease of the spine, sometimes as an isolated finding.