[Thin needle aspiration biopsy of the kidneys in diagnosis of acute pyelonephritis]

The aim of the study was to investigate the role of thin needle aspiration biopsy (TNAB) of the kidneys in differential diagnosis of serous and purulent pyelonephritis. TNAB of the kidneys under ultrasound control was made in 126 patients with acute pyelonephritis (AP). Renal aspirate and peripheral blood smears were stained according to May-Grunvald-Gimze. The number of immature and mature neutrophils, lymphocytes, eosinophils per 100 blood cells was counted as well as the increment of these cells in peripheral blood. Cytological tests of aspiration biopsy of the kidneys and peripheral blood have demonstrated that purulent-destructive forms of AP are characterized by a significant rise in the count of immature and mature neutrophils (by 15.7 +/- 1.2%, p < 0.001 and 16.8 +/- 3.2%, p < 0.001, respectively), deficiency of lymphocytes and monocytes, impairment of tubular cells in the renal biopsy. Cytological signs of purulent pyelonephritis were detected in 86 (68.2%) of 126 patients. This diagnosis was confirmed intraoperatively and histologically. No increment in the count of the above cells in puncture samples was found in 40 (31.8%) patients, so the diagnosis of purulent pyelonephritis in them was rejected. False positive results were obtained in 2 patients. Minor invasiveness, high informative value make TNAB of the kidney a useful tool in urgent diagnosis of acute pyelonephritis forms. In unclear situations this method should be used after 24 hours since the start of ineffective treatment.