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The mean annual incidence of hemolytic uremic syndrome in persons

OBJECTIVES. There has been intense discussion on the effectiveness of continuous antibiotic prophylaxis for children with vesicoureteral reflux, and randomized, controlled trials are still needed to determine the effectiveness of long-term antibiotics for the prevention of acute pyelonephritis. In this multicenter, open-label, randomized, controlled trial, we tested the effectiveness of antibiotic prophylaxis in preventing recurrence of pyelonephritis and avoiding new scars in a sample of children who were younger than 30 months and vesicoureteral reflux. METHODS. One hundred patients with vesicoureteral reflux (grade II, III, or IV) diagnosed with cystourethrography after a first episode of acute pyelonephritis were randomly assigned to receive antibiotic prophylaxis with sulfamethoxazole/trimethoprim or not for 2 years. The main outcome of the study was the recurrence of pyelonephritis during a follow-up period of 4 years. During follow-up, the patients were evaluated through repeated cystourethrographies, renal ultrasounds, and dimercaptosuccinic acid scans. RESULTS. The baseline characteristics in the 2 study groups were similar. There were no differences in the risk for having at least 1 pyelonephritis episode between the intervention and control groups. At the end of follow-up, the presence of renal scars was the same in children with and without antibiotic prophylaxis. CONCLUSIONS. Continuous antibiotic prophylaxis was ineffective in reducing the rate of pyelonephritis recurrence and the incidence of renal damage in children who were younger than 30 months and had vesicoureteral reflux grades II through IV.

PED MED CHIR

Many factors have been proposed as predictors of poor renal prognosis in children with hemolytic uremic syndrome (HUS), but their role is still controversial. Our aim was to detect the most reliable early predictors of poor renal prognosis to promptly identify children at major risk of bad outcome who could eventually benefit from early specific treatments, such as plasmapheresis. Prognostic factors identifiable at onset of HUS were evaluated by survival analysis and a proportional hazard model. These included age at onset, prodromal diarrhea (D), leukocyte count, central nervous system (CNS) involvement, and evidence of Shiga toxin-producing Escherichia coli (STEC) infection. Three hundred and eighty-seven HUS cases were reported; 276 were investigated for STEC infection and 189 (68%) proved positive. Age at onset, leukocyte count, and CNS involvement were not associated with the time to recovery. Absence of prodromal D and lack of evidence of STEC infection were independently associated with a poor renal prognosis; only 34% of patients D(-)STEC(- )recovered normal renal function compared with 65%-76% of D(+)STEC(+), D(+)STEC(-) and D(-)STEC(+ )patients. In conclusion, absence of both D and evidence of STEC infection are needed to identify patients with HUS and worst prognosis, while D(-) but STEC(+) patients have a significantly better prognosis.

Mutations in the COL4A5 gene, which encodes the a5 chain of type IV collagen, are found in a large fraction of patients with X-linked Alport syndrome. The recently discovered COL4A6, tightly linked and highly homologous to COL4A5, represents a second candidate gene for Alport syndrome. We analyzed 177 Italian Alport syndrome families by Southern blotting using cDNA probes from both COL4A5 and COL4A6. Nine unrelated families, accounting for 5% of the cases, were found to have a rearrangement in COL4A5. No rearrangements were found in COL4A6, with the exception of a deletion encompassing the 5' ends of both COL4A5 and COL4A6 genes in a patient with Alport syndrome and leiomyomatosis. COL4A5 rearrangements were all intragenic and included 1 duplication and 7 deletions. Polymerase chain reaction (PCR) analysis was carried out to characterize deletion and duplication boundaries and to predict the resulting protein abnormality. The two smallest deletions involved a single exon (exons 17 and 40, respectively), while the largest ones spanned exons 1 to 36. The clinical phenotype of patients in whom a rearrangement in COL4A5 was detected was severe, with progression to end-stage renal failure in juvenile age and hypoacusis occurring in most cases. These data have some important implications in the diagnosis of patients with Alport syndrome.