Cryptogenic tuberculosis as a preventable cause of end-stage renal failure.

A women with a history of urethral stenosis, not causing significant urinary tract obstruction but requiring dilation, presented at the age of 49 with renal failure (creatinine clearance of 16-20 ml/min). Investigations (including pyelography) directed to finding the cause of her renal failure were negative with the exception of renal biopsy which revealed granulomata, one of which showed caseation. Treatment with antituberculous drugs arrested the decline in glomerular filtration rate and was later associated with sustained improvement in renal function. Tuberculosis should always be considered as a possible cause of unexplained renal failure even if the classical pyelographic features of tuberculosis, i.e. calyceal distortion and calcification, are absent. Appropriate treatment may improve renal function and avert the need for renal replacement therapy.