Characteristics of pediatric rhabdomyolysis and the associated risk factors for acute kidney injury: a retrospective multicenter study in Korea

Background The clinical features of pediatric rhabdomyolysis differ from those of the adults with rhabdomyolysis; however, multicenter studies are lacking. This study aimed to investigate the characteristics of pediatric rhabdomyolysis and reveal the risk factors for acute kidney injury (AKI) in such cases. Methods This retrospective study analyzed the medical records of children and adolescents diagnosed with rhabdomyolysis at 23 hospitals in South Korea between January 2007 and December 2016. Results Among 880 patients, those aged 3 to 5 years old composed the largest subgroup (19.4%), and all age subgroups were predominantly male. The incidence of AKI was 11.3%. Neurological disorders (53.6%) and infection (39.0%) were the most common underlying disorder and cause of rhabdomyolysis, respectively. The median age at diagnosis in the AKI subgroup was older than that in the non-AKI subgroup (12.2 years vs. 8.0 years). There were no significant differences in body mass index, myalgia, dark-colored urine, or the number of causal factors between the two AKI-status subgroups. The multivariate logistic regression model indicated that the following factors were independently associated with AKI: multiorgan failure, presence of an underlying disorder, strong positive urine occult blood, increased aspartate aminotransferase and uric acid levels, and reduced calcium levels. Conclusions Our study revealed characteristic clinical and laboratory features of rhabdomyolysis in a Korean pediatric population and highlighted the risk factors for AKI in these cases. Our findings will contribute to a greater understanding of pediatric rhabdomyolysis and may enable early intervention against rhabdomyolysis-induced AKI

Hematuria and proteinuria in a mass school urine screening test

A total of 1,044 school children identified with hematuria and/or proteinuria during a mass school urine screening test were referred to pediatric nephrologists at 13 hospitals in Korea. These children had isolated hematuria (IH) (60.1%), isolated proteinuria (IP) (26.4%: transient, 19.6%; orthostatic, 4.9%; persistent, 1.9%) or combined hematuria and proteinuria (CHP) (13.5%). The patient's history, physical examination, laboratory tests, kidney ultrasound and Doppler ultrasonography were obtained. Renal biopsies were performed on 113 children who showed severe proteinuria, hypertension, abnormal renal function, family history of chronic renal disease, systemic diseases or persistent hematuria and/or proteinuria for more than 12 months. IgA nephropathy (IgAN), thin basement membrane nephropathy (TBMN), membranoproliferative glomerulonephritis (MPGN), focal segmental glomerulosclerosis (FSGS), other GN, Alport syndrome and lupus nephritis were detected. IgAN and TBMN were the most common causes in the CHP group and IH group, respectively. Abnormal findings on the renal ultrasound with or without Doppler ultrasonography were noted in 147 cases (suspected nutcracker phenomenon, 65; increased parenchymal echogenicity, 40; hydronephrosis, 15). This study showed that the use of a mass school urine screening program can detect chronic renal disease in its early stage and recommends that more attention should be paid to identifying those children with CHP and massive proteinuria. A school urine screening program can detect chronic renal disease in its early stage. When mass screening is used, the initial aggressive diagnostic procedures such as renal biopsy are not needed. In addition, a regular follow-up for those children with IH and IP is certainly warranted