ABSTRACT
BACKGROUND: Acute pyelonephritis (APN) is an unusual cause of acute renal failure (ARF) in patients without urinary obstruction and other predisposing conditions. Therefore, in the differential diagnosis of ARF, APN is rarely considered. METHODS: We retrospectively analyzed the data from the patients with ARF secondary to APN (ARF group, n=8) with normal renal anatomy and no known predisposing conditions which lead to ARF during the course of acute bacterial pyelonephritis, and investigated the differences of clinical parameters to the patients with uncomplicated APN (control group, n=20). RESULTS: Female were predominant in both groups. The mean age was 49.2+/-14.4 years in control group and 56.3+/-16.4 years in ARF group. On admission, the body temperature was 37.5+/-1.14degrees C in control group and 36.62+/-0.32degrees C in ARF group (p= 0.003). The days of pyuria, duration days of costovertebral angel (CVA) tenderness and hospitalization days were significantly prolonged in ARF group. CVA tenderness was unilateral in 65% of control group and bilateral in 65% of ARF group. Amounts of daily urine protein excretion were 0.15+/-0.48 gm/ day in control group and 2.99+/-2.89 gm/day in ARF group (p=0.001). Creatinine clearance and FeNa were 24.04+/-15.98 mL/min and 2.80+/-2.68 in patients group, respectively. Development of ARF had positive correlation with the duration of pyuria (r=0.579, p< 0.01), amounts of daily urine protein excretion (r=0.854, p< 0.01), duration of CVA tenderness (r=0.461, p< 0.05) and had a negative correlation with body temperature (r=-0.402, p< 0.05). CONCLUSION: APN is a rare but important cause of acute renal failure. Patients with ARF secondary to APN seems to have more prolonged period of pyuria and CVA tenderness, apyrexia and excrete more protein in urine than patients with uncomplicated APN. Adequate treatment of the bacterial infection by prompt antibiotic treatment may lead to full recovery of renal function.