[Role of the ultrasounds in the kidney biopsy: a case of postbiopsy hematoma linked to renal arteriovenous fistula].

In the planning of a kidney biopsy procedure, ultrasound examination has a crucial role before percutaneous renal biopsy (PRB) in detecting renal abnormalities that could contraindicate the biopsy; during PRB as a method to locate the kidney; and after PRB to diagnose and monitor postbiopsy complications. The case of a 40-year-old woman who underwent ultrasound-guided PRB for urinary abnormalities is described. Careful renal assessment by ultrasonography before the kidney biopsy was not performed. The post-PRB ultrasound examination revealed a perinephric hematoma along with an arteriovenous fistula (AVF) at the lower pole of the biopsied kidney. Surprisingly, a later renal angiography showed AVFs in both kidneys and therefore a diagnosis of non-iatrogenic, idiopathic AVFs was made. Based on our unusual case report, we discuss the diagnostic approach and therapeutic strategies for renal AVFs and we emphasize the usefulness of ultrasound for initial pre-PRB evaluation. In addition, with respect to the post-biopsy hematoma, the advantages offered by ultrasound during and after the implementation of PRB are debated. Finally, the role of post-biopsy hematoma as a possible indicator of post-PRB complications is reported.