99mTechnetium-dimercaptosuccinic acid scan in the diagnosis of acute pyelonephritis in children: relation to clinical and radiological findings

Abstract

Seventy-two children, 59 girls and 13 boys, 0.1-15.9 (median 1.1) years of age, with acute pyelonephritis (APN) were investigated with the aid of a dimercaptosuccinic acid (DMSA) scan, renal ultrasonography (US) and a desmopressin test within 5 days of admission. Sixty-two children were reinvestigated approximately 2 months later when intravenous urography (IVU) and micturition cysto-urethrography were also performed. During infection, 92% of the children showed changes in the DMSA scan with 69% by US, and the two investigations agreed in 58% of the kidneys. At follow-up, 68% showed changes in the DMSA scan, 47% by US and 48% by IVU. The DMSA scan and IVU agreed in 60% of the kidneys. Twenty-nine percent of the children had vesico-ureteric reflux (VUR). The presence of grade greater than or equal to 3 VUR was associated with greater defects on the DMSA scan during infection, and at follow-up with a higher frequency of persistent changes compared with no VUR (P less than 0.02 and 0.01, respectively). During infection the size of the defect on the DMSA scan correlated with renal volume and C-reactive protein and inversely with the glomerular filtration rate, and at follow-up it correlated inversely with the renal concentration capacity. The DMSA scan is a sensitive method for diagnosing and localizing APN in children, and findings on DMSA scan show a weak but significant correlation with routine clinical and radiological parameters. It is suggested that persistent renal damage after APN in children without VUR may be more common than previously assumed.

Risk factors of renal scars in children with acute pyelonephritis

“…Only 16 (20%) children had neurogenic bladder. The median duration of fever was 3 days (range [1][2][3][4][5][6][7][8][9][10][11][12][13][14]. Other paraclinical findings were as follows: CRP level of more than 6 mg/dL was reported in 61 (76.2%) children; leukocytosis in 42 (52.5%); and positive culture for Escherichia coli was obtained from 69 (86.2%) and the rest of the patients had other urinary microbial profiles.…”

“…UTI may be limited to the bladder, cystitis, or may involve the renal parenchyma, acute pyelonephritis (APN), defined as fever over 38.5ºC, high level of C-reactive protein or erythrocyte sedimentation rate, leucocyturia and positive urinary culture. 1 The clinical presentation of APN may be nonspecific and varies according to factors such as the patient's age and level of infection (whether the infection involves kidneys or lower urinary tract only). The renal cortical changes are acceptably detected by 99mTc-DMSA renal scintigraphy.…”

“…The renal cortical changes are acceptably detected by 99mTc-DMSA renal scintigraphy. 2 This method is applied in two ways: (1) to localize UTI during an attack to predict the risk of scarring; (2) to monitor the development of new scars; and/or (3) progression of existing scars in a serial…”

Cintilografia renal com ácido dimercaptossuccínico marcado com tecnécio no diagnóstico da pielonefrite na infância: estudo de 17 casos

“…Essas alterações secundárias ao processo inflamatório podem persistir de quatro a seis semanas após o tratamento da PNA, sem serem, necessariamente, definitivas. Quando detectadas precocemente pelo exame com DMSA, as alterações encontradas na fase aguda poderão desaparecer em 50 a 60% dos pacientes adequadamente tratados [13][14][15][16] .…”

“…Na última década vários trabalhos têm estudado as alterações encontradas na cintilografia renal com DMSA durante a PNA 14,[16][17][18][19][20][21][22] . Embora esses trabalhos variem em relação à população estudada, concordam nos seguintes aspectos: o dano ao parênquima renal é detectado pelo exame com DMSA durante a infecção aguda na maioria dos pacientes (50 a 80%) e o exame com DMSA alterado é raro em crianças com diagnóstico de cistite 23,24 .O objetivo deste estudo é analisar se a presença de alterações na cintilografia renal com DMSA na fase aguda da infecção urinária pode ser indicadora de pielonefrite.…”