Endobronchial Tuberculosis

Definition: Active pneumonic or cavitary disease may shed infected secretions into local bronchi. Organisms may also be aspirated into other bronchi to give rise to more distant endobronchial disease. Several sequelae may occur: bronchiolitis obliterans, bronchocentric granulomatosis, bronchiectasis, or bronchostenosis.

Upper lobe cavitary disease with endobronchial spread: Here, an upper lobe tuberculous cavity with a shaggy wall has discharged its organisms into airways. Disease has spread into bronchi in the upper, as well as the lower, lobe. Infected bronchi appear as small, pale nodules with a hyperemic border (arrow marks one in the lower lobe).

CT changes: The anterior portion of the RUL shows consolidation, as well as adjacent centrilobular nodules and tree-in-bud pattern that indicate endobronchial spread of disease in small bronchi and bronchioles. These obstructive airway lesions result in a mosaic pattern of low attenuation in the surrounding parenchyma. This mosaic pattern can also be seen in the posterior-medial region of the right lung. The mosaic pattern is accentuated on end expiratory CTs and may persist after therapy.

 

CT changes: Mediastinal window of the CT image above shows central low attenuation in the RUL focal consolidations, indicating central necrosis. Also note the right paratracheal lymph node, which shows central low attenuation, a common finding with active tuberculosis.

Bronchocentric granulomatosis/bronchiectasis: Histologically, this medium-sized bronchus shows destruction of the wall structures by a diffuse, granulomatous inflammation. The dilated lumen is obstructed by a mucoid exudate. This type of active disease may develop by spread of organisms via the airway or by lymphatic spread in the bronchial wall. By CT the bronchial wall would appear thickened and the lumen dilated, a sign of bronchial disease.

Clinical summary Endobronchial disease & adenopathyDiscussion

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