[The use of renal ultrasound for adult acute pyelonephritis]

To evaluate the need to perform renal ultrasound (US) in adult patients with acute pyelonephritis (APN).

A Review of the bibliography in the data bases PubMed and Cochrane Collaboration about the use of the ultrasonography in the evaluation and diagnosis of APN.

Thirty-seven papers were found, but only 5 fulfilled the requirements for analysis. Four hundred and sixty three patients diagnosed of APN were revised, 449 (977) of whom got US. Between 171 ultrasonographic findings, only in 52 (11.5%) cases US findings changed initial diagnosis to complicated APN that could lead to surgery.

The low incidence of ultrasonographic findings does not justify the practice of renal US to every patient with APN. In patients with persistent fever longer than 72 hours, antecedents of anomalies of the urinary tract, antecedents of renal lithiasis, pregnancy, atypical clinic or diabetes mellitus, there is a higher incidence of pathological US findings that justify a change in the therapeutic approach. Further prospective clinical studies are needed to confirm these conclusions.