Presentation, diagnosis, and treatment outcome of tuberculous-mediated tubulointerstitial nephritis.

Insidious Mycobacterium tuberculosis infection causing tubulointerstitial nephritis is a rare disorder. Here we report on a single-center case series of patients with tubulointerstitial nephritis due to tuberculosis, addressing clinicopathologic features and treatment outcome. Twenty-five adult patients with clinical evidence of tuberculosis and significant renal disease were assessed, 17 of whom had a kidney biopsy and were subsequently diagnosed with chronic granulomatous tubulointerstitial nephritis as the primary lesion. All patients were given standard antitubercular treatment, with some receiving corticosteroids, and showed a good response in clinical symptoms and inflammatory markers. Nine of the 25 patients, however, started renal replacement therapy within 6 months of presentation. Of the remaining 16, renal function improved for up to a year after presentation but subsequently declined through a median follow-up of 36 months. This case series supports that chronic tubulointerstitial nephritis is the most frequent kidney biopsy finding in patients with renal involvement from tuberculosis. Thus, a kidney biopsy should be considered in the clinical evaluation of kidney dysfunction with tuberculosis since tubulointerstitial nephritis presents late with advanced disease. A low threshold of suspicion in high-risk populations might lead to earlier diagnosis and treatment, preserving renal function and delaying initiation of renal replacement therapy.