Renal tuberculosis

Abstract

Tuberculosis (TB) is a disease caused in most cases by Mycobacterium tuberculosis, and is currently a public health problem. Extrapulmonary TB cases have become more common since the appearance of the human immunodeficiency virus (HIV) and the increase in organ transplants and the consequent drug immunosuppression. The main extrapulmonary TB sites are pleural, lymphatic, and urogenital TB. Urogenital TB occurs through hematogenous dissemination and, like other forms of TB, is more frequent in immunosuppressed patients. Renal manifestations of TB include proteinuria, hematuria, hypoalbuminemia, and renal dysfunction. The histopathological findings include interstitial inflammatory infiltrate, mesangial proliferation, and interstitial granulomas, among others. The association between M. tuberculosis infection and interstitial nephritis demonstrates the usually observed chronic course of the infection. Renal impairment in TB may be part of a disseminated infection or be localized in the genitourinary tract. In both cases, the lesions depend basically on the patient’s immune status, pathogenicity of the bacillus, and site of infection. Pulmonary infection is the primary site in most cases. After exposure to the bacillus, the latter remains stored in the macrophages where they slowly multiply. In most cases, the primary infection is self-limiting. The kidneys are commonly affected in cases of miliary TB, where miliary lesions measuring up to 3 mm in diameter are found in renal tissue (mainly cortical) from the hematogenous dissemination. The treatment of TB contributes to the reduction in alterations found in the urinary sediment, as well as to renal function improvement.