Sell

reactivation of dormant primary lesions many decades after initial infection, particularly when host resistance is weakened; or reinfection

apex of one or both upper lobes is the most common site due to high oxygen tension in the apices

cavitation occurs readily in the secondary form, resulting in dissemination along the airways

persons with AIDS and advanced immunosuppression (CD4+ counts less than 200 cells/mm3)

clinical picture that resembles progressive primary tuberculosis

sputum-smear negativity due to absence of tissue (bronchial wall) destruction due to suppressed type IV hypersensitivity

negative PPD because of tuberculin anergy

lack of characteristic granulomas in tissues

Erosion into a bronchus evacuates the caseous center, creating a ragged, irregular cavity

Erosion of blood vessels results in hemoptysis

Miliary pulmonary disease occurs when organisms drain through lymphatics into the lymphatic ducts, which empty into the venous return to the right side of the heart and thence into the pulmonary arteries

pleural effusions, tuberculous empyema, or obliterative fibrous pleuritis

Endobronchial, endotracheal, and laryngeal tuberculosis

tuberculous meningitis

renal tuberculosis

Addison disease( adrenal TB)

Salpingitis( chronic PID)

Pott disease and Paraspinal "cold" abscesses

Lymphadenitis ( scrofula, cervical LN common)

intestinal tuberculosis: organisms are trapped in mucosal lymphoid aggregates of the small and large bowel, which then undergo inflammatory enlargement with ulceration of the overlying mucosa, particularly in the ileum.

When soft, necrotic center drain out leave behind a cavity.

Cavitation is typical for large granulomas.

Cavitation is more common in the reactivation tuberculosis seen in upper lobes.

Extensive infection

Hematogenous spread

Low immunity

Pulmonary or Systemic types.

Secondary TB.