Evaluation of acute pyelonephritis with DMSA scans in children presenting after the age of 5 years

Abstract

It is generally believed that infants are more susceptible to development of renal scarring after pyelonephritis than children over 5 years old. This view has led to differences in investigations and treatment according to age. The aim of this prospective study was to assess the occurrence of renal parenchymal lesion in children over 5 years admitted with a first-time symptomatic urinary tract infection (UTI). Between October 2000 and April 2002, 52 children aged over 5 years who were admitted to our department with probable acute pyelonephritis (APN) and a positive urine culture were included in this study. All children received antibiotics for 14 days. During the acute phase of infection, scintigraphy with technetium-99m-labeled dimercaptosuccinic acid (DMSA) and ultrasonography (US) were done. Voiding cystourethrography (VCUG) was performed in all children early in the course of the illness, generally within 5-7 days of hospitalization. When scintigraphy showed renal parenchymal changes, repeat scintigraphy was done after at least 3 months to assess the progression of renal abnormalities. Of the 52 children with a first-time documented pyelonephritis, cortical scintigraphy showed renal lesion in 41 children (78.8%). US was normal in all children with normal renal scintigraphy, while it detected renal abnormalities in 16 of the 41 (39 %) with abnormal scintigraphy (p <0.0001). Topographic analysis of the 165 focal lesions showed that 42.4% were localized to the upper poles, 17.5% to the middle third, and 40% to the lower poles of the kidneys. Repeat scintigraphy showed persistent lesions corresponding to those on the initial scan in nine (28.2%) of the 32 children. Renal lesions had partly regressed in 23 (71.8%) of the patients who underwent repeat scintigraphy. Vesicoureteral reflux was observed in 13.4% of kidneys and renal parenchymal abnormalities were identified in 71.4% and 72.2% of renal units, respectively, with and without reflux ( p >0.05). In conclusion, our data did not confirm the conventional opinion that the risk of renal scarring after pyelonephritis is low in children over the age of 5 years. Our findings suggest that renal scintigraphy may be a more appropriate method of investigation than VCUG for evaluation of the children over 5 years with acute pyelonephritis. Additionally, the frequency of scintigraphic changes is high, and a strategy based exclusively on ultrasound findings would miss about 61% of the abnormal renal units. We recommend that all children, irrespective of age, will benefit from further investigations that might prevent or limit the development of scarring process and renal complications.

Renal Scarring in the Randomized Intervention for Children with Vesicoureteral Reflux (RIVUR) Trial

“…Are infants truly at a higher risk of renal scarring with APN compared with older children, as initially reported in the International Reflux Study (16) and subsequently endorsed by others (17,18). Recent studies have already questioned this conventional wisdom by reporting that younger age may not be a risk factor for renal scarring (19,20); the risk in older children may even be higher (21,22). In addition, the recommendation by the American Academy of Pediatrics and National Institute for Health and Clinical Excellence guidelines (23,24) to delay VCUG until the second episode of UTI may need to be reviewed.…”

Diagnostic significance of clinical and laboratory findings to localize site of urinary infection

“…It may involve the upper (acute pyelonephritis) and/or the lower (cystitis, urethritis) urinary tract. Renal scarring is present in 8-40% of patients after an episode of acute pyelonephritis [2][3][4][5][6][7][8]. As a result of the renal scars, patients may develop hypertension and variable degrees of renal failure [9].…”

Characteristics of urinary tract infections in children up to 7 years of age

“…Djeca od dvije do šest godina sa febrilnom IUT obično imaju znake sistemske bolesti uz gubitak apetita, iritabilnost, bol u abdomen i slabinama, sa ili bez poremećaja mokrenja. Djeca sa akutnim cistitisom mogu imati simptome poremećaja mokrenja kao hitno i učestalo mokrenje, dizuriju, inkontinenciju [29][30][31][32][33][34][35][36]. U djece iznad šest godina klasični simptomi IUT su izrazitiji.…”

“…Posljednjih se godina sve veće značenje u dijagnostici akutnih upalnih bolesti bubrega pridaje magnetnoj rezonanci (MR) [34]. MR je naročito vrijedna u dijagnostici akutnog pijelonefritisa i bubrežnog ožiljavanja, a u situacijama u kojima je ožiljak manji pa ne postoji izmjena spoljašnje konture bubrega, MR je uspješnija od DMSA scintigrafije u razlikovanju akutnog pijelonefritisa od ranije nastaloga ožiljka [34][35][36][37]. U direktnom poređenju MR sa DMSA scintigrafijom kao zlatnim standardom, osjetljivost MR u procjeni postojanja ožiljava-…”

“…Iako mogućnosti MR dijagnostike bubrega obećavaju, ne samo u prikazu akutnog pijelonefritisa i ožiljavanja, a uz to ne postoji ni radioaktivno zračenje, širu primjenu MR za sada ograničava skupoća pretrage i potreba sedacije/opšte anestezije za izvođenje pretrage u manje djece [34,[35][36][37][38][39][40]. U tabeli 2 mogu se vidjeti smjernice za radiološku obradu djeteta sa IUT [21].…”