Urinary tract infections (UTI) are common in childhood. Presence of pyuria and bacteriuria in an appropriately collected urine sample are diagnostic of UTI. The risk of UTI is increased with an underlying urological abnormality such as vesicoureteral reflux, constipation, and voiding dysfunction. Patients with acute pyelonephritis are at risk of renal scarring and subsequent complications such as hypertension, proteinuria with and without FSGS, pregnancy-related complications and even end-stage renal failure. The relevance and the sequence of the renal imaging following initial UTI, and the role of antimicrobial prophylaxis and surgical intervention are currently undergoing an intense debate. Prompt treatment of UTI and appropriate follow-up of those at increased risk of recurrence and/or renal scarring are important.

BackgroundIdiopathic nephrotic syndrome (INS) is a common pediatric disease. Minimal change disease (MCD) is the most common histopathological subtype and usually has good prognosis. However, in less common presentations, INS may have an unusual course that makes renal biopsy a necessity to identify its etiology. Immunoglobulin M (IgM) occasionally deposits in the mesangium and can be seen under immunofluorescence (IF). The role of IgM is controversial in MCD. It is likely associated with less favorable outcomes for MCD. This study aims to investigate the clinical significance of mesangial IgM deposits on the outcome of MCD in a pediatric population.MethodsIn this retrospective cohort study, we obtained native kidney biopsy samples from 192 children who were diagnosed with MCD from 2003 to 2014. The samples were divided into groups according to the histopathological deposition of IgM in biopsies under IF. The group for which biopsies showed IgM was labeled as IgM + IF (n = 77), and the group for which biopsies were without IgM was labeled as IgM-IF (n = 115). We reviewed hypertension, hematuria, and estimated glomerular filtration rate (eGFR) at the time of presentation to our institute; response to steroid therapy (remission, dependence, frequent relapses, and resistance) and response after adjuvant immunosuppressive therapy (complete remission, partial remission, frequent relapses, and no response) when indicated; development of chronic kidney disease (CKD) and end-stage renal disease during the course of the disease (ESRD).ResultsOur results showed that mesangial IgM deposition in MCD showed significant statistical association with hypertension at the time of presentation (P = .05). There was statistically significant association between the presence of IgM deposition and the development of steroid dependence (P = .05) and CKD during the course of the disease (P = .05).ConclusionsOur study showed that IgM deposition in MCD showed statistical association with hypertension by the time the patient presented to our institute, development of steroid dependence, and CKD. IgM may play a role in MCD. However, we recommend a prospective study to verify the role of IgM in MCD outcomes.

Although prednisone is the treatment of choice for nephrotic syndrome (NS) in childhood, the dosing regimen varies between 60 mg/m(2)/day, as recommended in early studies, to the often prescribed 2 mg/kg/day dose, which is used in common practice. Mathematical models have demonstrated that weight-based dosing can be less than body surface area (BSA)-based dosing in smaller children. To test our hypothesis that weight-based dosing would result in altered treatment outcomes in children with NS, we analyzed a cohort of 56 children (mean age 5.4 ± 3.8 years) treated with a weight-based dosing regimen. Theoretical underdosing of corticosteroids was tested by calculating a relative underdosing percentage (RUP), which was defined as the dose difference between the theoretical BSA-based dose and the actual weight-based doses divided by the BSA-based dose × 100. We found that the mean "actual" prednisone dose in our patients was 43.6 ± 19.3 mg/day; in contrast, the mean theoretical BSA-based dose was calculated to be 48.8 ± 16.7 mg/day. Among the 56 patients, 43 (76.7%) were initial responders, of whom 58% followed a frequently relapsing (FR) course. RUP was significantly higher in FR (16.6 ± 7.9%) than in infrequent relapsers (8.7 ± 9.8%) (P = 0.03). RUP was not significantly different among initial responders and nonresponders. Based on these results, we conclude that prednisone underdosing, when dosing is prescribed according to weight, does not affect the initial response to treatment, but it does increase the likelihood of a FR course in responders.

Iron deficiency (ID) contributes to the development of anemia in patients with chronic kidney disease (CKD). The frequency of ID in children with early CKD has not previously been reported. This was a retrospective chart review of children with CKD stages 2 and 3 followed at the CKD clinic of Children's Hospital of Michigan. ID was defined as low ferritin and transferrin saturation <20%. Patients on iron supplements were considered as iron-deficient cases. There were 50 patients included in the study (72% male) with a mean age of 10.31 (±5.21). The mean glomerular filtration rate (GFR) was 55.4 ml/min/1.73 m(2) (±14.61). ID was present in 42% of patients, out of whom almost half (42.9%) presented with anemia. Females had a higher frequency of ID (64.3%). The frequency of ID with anemia increased from 4.3% to 29.6%, (p = 0.03) in stage 2 to stage 3 CKD, respectively. The frequency of ID without anemia also increased with progression of CKD from stage 2 to stage 3, however, the difference was not statistically significant. ID is frequent in patients with early CKD. Monitoring of iron tests and treatment of ID is important in this population of patients.