Renal Parenchymal Damage in Male Infants with High Grade Vesicoureteral Reflux Diagnosed After the First Urinary Tract Infection:

Acute Tc-99m DMSA scan for identifying dilating vesicoureteral reflux in children: a meta-analysis

Controversy exists regarding the type and/or sequence of imaging studies needed during the first febrile urinary tract infection (UTI) in young children. Several investigators have claimed that because acute-phase Tc-99m dimercaptosuccinic acid (DMSA) renal-scan results are abnormal in the presence of dilating vesicoureteral reflux, a normal DMSA-scan result makes voiding cystourethrography (VCUG) unnecessary in the primary examination of infants with UTI. To evaluate the accuracy of acute-phase DMSA scanning in identifying dilating (grades III through V) vesicoureteral reflux documented by VCUG in children with a first febrile UTI, we performed a meta-analysis of the accuracy of diagnostic tests as reported from relevant studies identified through the PubMed and Scopus databases. Patient-based and renal unit-based analyses were performed. Overall, 13 cohort studies were identified. Nine studies involved patients younger than 2 years, 3 involved children aged 16 years or younger, and 1 involved exclusively neonates. Girls constituted 22% to 85% of the involved children. Pooled (95% confidence intervals) sensitivity and specificity rates of DMSA scanning were 79% and 53%, respectively, for the patient-based analysis (8 studies) and 60% and 65% for the renal unit-based analysis (5 studies). The respective areas under the hierarchical summary receiver operating curves were 0.71 and 0.67. Marked statistical heterogeneity was observed in both analyses, as indicated by I(2) test values of 91% and 87%, respectively. Acute-phase DMSA renal scanning cannot be recommended as replacement for VCUG in the evaluation of young children with a first febrile UTI.

Predictive risk factors for chronic renal failure in primary high-grade vesico-ureteric reflux

OBJECTIVE

To evaluate and define the risk factors predictive of chronic renal failure (CRF) in children with severe bilateral primary vesico-ureteric reflux (VUR), observed within the first year of life and with a long follow-up.

PATIENTS AND METHODS

The study comprised 50 patients presenting with grade 3-5 bilateral VUR diagnosed in the first year of life; 12 were suspected prenatally and confirmed shortly after birth, before any urinary tract infection (UTI). The mean (range) follow-up was 6.3 (1-16) years. The variables considered within the first year of life were: gender, prenatal diagnosis with no UTI, number of febrile UTIs, serum creatinine and urea nitrogen levels, metabolic acidosis, proteinuria, 24-h urine output, hypertension, bilateral renal length on ultrasonography and renal scarring on renal scintigraphy. CRF was defined as a creatinine clearance of <80 mL/min/1.73 m(2) at the last follow-up. The results were assessed using univariate and multivariate analyses (backward-stepwise multiple regression) of the selected variables.

RESULTS

CRF was detected at the last follow-up in 27 patients (54%), all boys, while renal function was normal in 23 (46%; seven girls). None of the 12 patients with prenatal diagnosis had UTI, but six had CRF. Febrile UTI was the presenting symptom in 38 (76%) patients and 17 (34%) of them had renal scarring. There was no significant difference between the prenatally detected VUR and febrile UTI group in the outcome as CRF. The univariate and multiple regression analysis showed that the first serum creatinine threshold of >6 mg/L before 1 year old was the most significant risk factor for CRF (P < 0.001; odds ratio 1.25).

CONCLUSIONS

Children with primary bilateral high-grade VUR and a serum creatinine of > 6 mg/L in the first year of life have a significant risk of developing CRF in the long-term. Prenatal diagnosis and postnatal febrile UTI do not modify the outcome for renal function.