Renal arteriovenous fistula simulating hydronephrosis: A case report.

INTRODUCTION: Acquired renal arteriovenous fistulas (AVFs) include those that occur as a complication of renal biopsy. CASE REPORT: The authors report the case of a woman with recent-onset grade I hypertension, who was referred to our staff for sonographic studies of the kidneys and urinary tract. Laboratory data revealed microhematuria and proteinuria <0.5 g/24 h, and renal function was borderline (MDRD GFR 58 mL/min). Renal sonography of the left kidney revealed an anechoic, arboriform area at the level of the pelvis, which was suggestive of hydronephrosis. The color Doppler examination showed turbulent flow within the anechoic area, with high-velocity arterial flow and arterialization of the venous waveform at spectral analysis. Selective renal angiography later confirmed the presence of a middle renal AVF with pseudoaneurysm, which had been provoked by a renal biopsy performed over 10 years earlier in another center. Since the patient was currently in good health, the prescribed management consisted solely of close clinical and US follow-up. DISCUSSION: AV fistulas are among the most commonly diagnosed renovascular malformations. The case reported here underlines the importance of using color Doppler ultrasound when obstructive uropathy is suspected, especially in patients who have undergone renal biopsy.