Acute renal failure of unknown origin. Don't forget renal tuberculosis

reduced to a thin shell; a moderate dilatation of the Introduction collecting system was demonstrated in the left kidney. After contrast media injection, the right kidney was Renal tuberculosis is not mentioned in the current not visualized, while the left kidney revealed pyelocalliterature among the various causes of acute renal iectasis secondary to the presence of a stricture at the failure (ARF) [1,2]. We report for the first time that level of the pyeloureteral junction, which was associobstructive ARF may be caused by tuberculosis and ated with a moderately restricted left ureter (Figure 1). reversed by medical therapy. There were no genitourinary calcifications. The right kidney was removed with no change in the renal function. The histopathological examination led to the Case report diagnosis of tuberculous pyonephrosis. We started treatment with isoniazid (300 mg/day), rifampicin A 46-year-old woman was admitted with epigastric (600 mg/day), and ethambutol (400 mg/day). Six pain and dyspepsia. She reported symptoms of gastmonths of this therapy progressively reduced the values ritis, occasionally treated with anti-H2 drugs. Past of plasma creatinine and urea levels to 106 mmol/l and medical history included insulin-dependent diabetes 6.5 mmol/l respectively, associated with improvement mellitus for about 20 years associated with marked of creatinine clearance (71 ml/min) and urinary abnordiabetic retinopathy, slight reduction of renal function malities (5 red blood cells and 5 white blood cells per (plasma creatinine level of 106 mmol/l, creatinine clearhigh-power field). The renal echography demonstrated ance of 69 ml/min), proteinuria less than 1 g/day, complete remission of the obstruction. moderate erythrocyturia and leukocyturia. On admission, no other symptom was detected and gastroprotective drugs relieved the gastric pain. The biochemical Comment assessment showed increased plasma creatinine (177 mmol/l ) with a creatinine clearance of 28 ml/min, urea (11.5 mmol/l ), glycaemia (5.5 mmol/l ), and diurThis case depicts renal tuberculosis (TB) as a cause of esis (900 ml/day), with normal blood pressure obstructive ARF. In our patient the lack of a previous (130/80 mmHg). Urinalysis revealed erthrocyturia (10 diagnosis of renal TB was probably due both to the cells per high-power field ) and leukocyturia (10 cells absence of urinary and systemic symptoms of TB and per high-power field) with a pH of 6.0 and a specific to the urinary and renal function abnormalities that gravity of 1.015. An increase in erythrocyte sedimentacould be attributed to the long-term diabetic nephrotion rate (56 at the 1st hour) was associated with a pathy. Indeed, more insights were attained only after moderate degree of anaemia (Hct=35%). All other the incidental discovery of ARF. The unilateral ureteral examinations including white blood-cell count and stricture, which was probably secondary to the presence chest radiography were within normal limits. of mucosal tuberculous nodules at the level of the Prerenal and toxic causes of renal failure were ureteropelvic junction, and the combined absence of excluded by careful anamnesis and clinical and laboratcontralateral renal function, accounted for the developory assessment. To investigate postrenal causes of ment of ARF. The short-term antituberculous therapy impaired renal function, the patient underwent sequenled to the remission of ARF. Notably, no previous tial radiographic examinations (echography, urograreports of similar cases appear in the current literature. phy, and computerized tomography). These The clinical manifestations of renal TB are generally examinations revealed a right kidney of increased size unilateral and involve about 3% of all TB patients [3]. with gross cavities in which the renal parenchyma was Bilateral advanced renal TB, similar to the case presented, is considered as a unusual cause of chronic renal failure [4], and it is not even mentioned among Correspondence and o print requests to: Prof. Giuseppe Conte, the various causes of ARF [1,2]. It is important to Division of Nephrology, Second University of Naples, Via Luigi Caldieri 10, 80127 Naples, Italy. underline that TB is a re-emergent infection. Indeed