DMSA RENAL SCANS IN ADULTS WITH ACUTE PYELONEPHRITIS

The Tc-99m-DMSA scan is accepted as the most sensitive imaging modalit y for detecting areas of renal parenchymal scarring. More recently the DMSA scan has also been shown to be of value in imaging areas of rena l parenchymal involvement in both children and adults with acute pyelo nephritis. We assessed the acute DMSA scan findings in a consecutive s eries of 81 patients hospitalized with acute pyelonephritis. Acute pye lonephritis was diagnosed if the patient had a fever of >37.8 degrees C, loin pain or tenderness and infected urine (99% Escherichia coli). Patients had a blood culture taken (8 positive), as well as a hematolo gical (leukocytosis 75%) and biochemical screen, C-reactive protein (C RP) (increased in 57 of 66 [86%]) and urinary tract ultrasonography. I f the initial DMSA scan was abnormal it was repeated after three month s and in some instances again at six months. If persisting defects wer e noted an intravenous urogram was then undertaken. Of the 81 patients , 37 (46%) had an abnormality on the DMSA scan. Nineteen had a single defect, 12 multifocal defects, five features suggestive of pre-existin g renal parenchymal scarring (all later shown to have reflux nephropat hy) and one a shrunken kidney. Those patients with an abnormal scan ha d a higher CRP concentration than those with a normal scan. Of the 31 patients who had either a focal or multifocal defect on their initial DMSA scan there was adequate follow-up on 24 patients. In 18 of these the defects had resolved by six months (usually within three months), while of the remainder, three were shown to have reflux nephropathy, o ne had a large single renal cyst and another an area of parenchymal ca lcification. Fifty-three of 76 patients (70%) had normal ultrasonograp hy. In adults with acute pyelonephritis, the DMSA scan may prove to be the most useful renal imaging procedure.