PROGNOSIS

In the developed world, tuberculosis is rarely a cause of chronic kidney disease. Preservation of renal function, however, depends on early detection to limit renal parenchymal destruction. In developing countries, where diagnosis and treatment are more likely to be delayed, permanent loss of renal function is more common.

MILIARY TUBERCULOSIS

In addition to being the site of locally reactivating granulomas, as described previously, the kidneys may rarely be involved in the disseminated disease known as miliary tuberculosis.

Miliary tuberculosis results from widespread hematogenous dissemination of tuberculous bacilli after invasion of the pulmonary circulation. It may occur during the time of primary infection or at reactivation, and it is often associated with the extremes of age and other conditions that compromise the immune system.

Patients have more pronounced constitutional systems and extensive pulmonary disease. Overwhelming systemic illness may overshadow the effects of renal involvement. The workup of miliary tuberculosis includes acid-fast bacillus smears, culture, PCR, and histopathologic examination of affected tissues (e.g., bone marrow, lymph nodes, liver). If the kidney is affected, numerous granulomatous lesions may be present throughout the cortex and, less commonly, the medulla. On microscopic examination these granulomas reveal central caseous necrosis.

Rapid diagnosis of military tuberculosis is essential, and treatment with the combination regimen described above should be promptly initiated.