Accuracy of diagnosing acute kidney injury by assessing urine output within the first week of life in extremely preterm infants.

BACKGROUND: Neonatal acute kidney injury (AKI) is associated with increased mortality and is often assessed with the neonatal modified Kidney Disease: improving Global Outcomes (KDIGO) classification, which uses changes in serum creatinine levels. However, because this classification has many drawbacks, a novel method, the neonatal Risk, Injury, Failure, Loss, and End-Stage Kidney Disease (nRIFLE) classification for diagnosing neonatal AKI according to urine output (UO), was recently proposed. To date, no data on the incidence of AKI according to nRIFLE are available for extremely preterm infants (born at gestational age less than 28 weeks). This study was conducted to clarify the association between incidence of AKI and in-hospital mortality in extremely preterm infants. METHODS: Of 171 extremely preterm infants hospitalized from 2006 to 2020, 84 in whom indwelling bladder catheters were placed for UO measurements within 24 h of life were included. The incidence of AKI was assessed using the nRIFLE classification. In-hospital mortality was compared between patients with AKI and those without it. RESULTS: The incidence of AKI during the first week of life was 56% and that of in-hospital mortality was significantly higher in patients with AKI (25.5%) than in those without it (2.8%). The odds ratio was 12.3 with 95% confidence interval ranging from 1.5 to 100.0. CONCLUSION: The incidence of AKI according to nRIFLE was higher than reported in most previous studies using the neonatal modified KDIGO classification, suggesting that assessment by nRIFLE criteria using UO may improve diagnostic accuracy of AKI in extremely preterm infants.

Idiopathic nephrotic syndrome in children: role of regulatory T cells and gut microbiota.

BACKGROUND: We investigated whether an association exists between regulatory T cells (Tregs) during initial presentation in children with idiopathic nephrotic syndrome (INS) and later development of frequently relapsing INS. METHODS: Blood samples were obtained at onset and at remission from 25 patients (median age, 4.0 years) with INS; eight did not show relapse after initial response (non-relapsing [NR]), whereas 17 showed frequent relapses (frequently relapsing [FR]). Tregs were measured by flow cytometry; increases were compared between groups. Fecal samples were obtained at onset from 20 patients with INS, as well as from 20 age-matched healthy children. Gut microbiota composition was assessed using 16S ribosomal RNA (rRNA) sequencing (ion PGM). RESULTS: The rate of increase in Tregs from onset to remission was significantly lower in the FR group (124.78%) than in the NR group (879.16%; P < 0.001). Additionally, 16S rRNA sequencing of gut microbiota showed that the proportion of butyric acid-producing bacteria was significantly lower in the FR group (7.08%) than in the healthy children (17.45%; P < 0.001). CONCLUSIONS: In children with INS, small increases in Tregs in response to steroid treatment were associated with subsequent increased risk of frequent relapses. In addition, the FR group had a greater degree of dysbiosis at onset. IMPACT: A low rate of Tregs increase is associated with subsequent frequent relapses of INS. The increase in Tregs in response to steroid treatment was small when dysbiosis was present in patients with INS, particularly when the proportion of butyrate-producing bacteria was considerably reduced We presume that improvement of dysbiosis by administration of probiotics and prebiotics may enhance the rate of Tregs' increase, thus preventing frequent relapse.

Reduced urinary excretion of neutrophil gelatinase-associated lipocalin as a risk factor for recurrence of febrile urinary tract infection in children.

BACKGROUND: This study aimed to test the hypothesis that reduced urinary excretions of neutrophil gelatinase-associated lipocalin (NGAL) predispose children to recurrence of febrile urinary tract infection (fUTI). METHODS: Subjects were 38 children diagnosed with fUTI. To examine risk factors for recurrence of fUTI, the subjects were divided into a non-recurrent group and a recurrent group according to the presence or absence of fUTI over 3 years since the first episode. We measured the urinary NGAL levels in patients with fUTI at the non-infected stage in addition to age-matched healthy control children. RESULTS: In a multiple logistic regression analysis, significant differences between the groups were not observed for age, sex, the prevalence of kidney scarring and bladder bowel dysfunction, urinary ß2-microglobulin/creatinine (Cr) level, and serum levels of Cr and Cystatin C, while the recurrent group had significantly more cases with grade III or higher vesicoureteral reflux (p < 0.01). Furthermore, the urinary NGAL/Cr in the recurrent group (median, 3.60 µg/gCr) was significantly lower than that in the non-recurrent group (median, 16.47 µg/gCr; p < 0.01), and age-matched healthy control children (median, 14.14 µg/gCr; p < 0.05). The area under the receiver operating characteristic curve of NGAL/Cr was 0.86 for predicting recurrence of fUTI. A cut-off value of 11.59 µg/gCr had the best accuracy to predict recurrent fUTI yielding a specificity of 78% and a sensitivity of 93%. CONCLUSIONS: Reduced levels of urinary NGAL, which protects against urinary infection, are a risk factor for recurrence of fUTI and could serve as a biomarker.

Superiority of Cystatin C over Creatinine for Early Diagnosis of Acute Kidney Injury in Pediatric Acute Lymphoblastic Leukemia/Lymphoblastic Lymphoma.

The exact incidence of acute kidney injury (AKI) during chemotherapy for acute lymphoblastic leukemia (ALL)/lymphoblastic lymphoma (LBL) is unknown. Furthermore, childhood cancer survivors are at risk of AKI-chronic kidney disease transition. Thus, early diagnosis of AKI is crucial. This study aimed to elucidate the incidence of AKI in patients undergoing chemotherapy for pediatric ALL/LBL and to compare the usefulness of serum cystatin C (CysC)- and creatinine (Cr)-based estimated glomerular filtration rate (eGFR) as diagnostic measures. Data of 16 patients with ALL/LBL treated with a total of 75 courses of chemotherapy were retrospectively analyzed. CysC- and Cr-based eGFR were measured before and three times per week during therapy. To calculate the eGFR, an equation for Japanese children was used. AKI was diagnosed when eGFR dropped by ≥ 25% from the highest eGFR value obtained during the latest 2 weeks since the start of chemotherapy. AKI was graded based on the pediatric Risk, Injury, Failure, Loss, End Stage Renal Disease scale. All patients developed AKI during chemotherapy; however, more than 90% of the cases were mild and eventually recovered. No significant differences were found in the incidence of AKI between CysC- and Cr-based eGFR (p = 0.104). The median time to AKI diagnosis was significantly shorter in the CysC-based eGFR than in the Cr-based eGFR (8 vs. 17 days, p < 0.001). In this study, all patients with pediatric ALL/LBL could develop mild AKI during treatment. CysC-based eGFR is a more effective measure than Cr-based eGFR for the early diagnosis of AKI.

Desmopressin response in nocturnal enuresis without nocturnal polyuria in Japanese children.

OBJECTIVES: To evaluate whether the efficacy of desmopressin differs between patients with and without nocturnal polyuria. METHODS: A total of 65 treatment-naïve children with monosymptomatic nocturnal enuresis were enrolled (45 boys; median age 8.9 years). Patients received desmopressin as their first-line treatment. Four different standards were used (Akashi and Hoashi >0.9 mL/kg/sleeping hour; Hamano >[age + 2] × 25 × 130% mL; the International Children's Continence Society >[age + 1] × 30 × 130% mL; and Rittig >[age + 9] × 20 mL) to assess nocturnal polyuria. The effectiveness of desmopressin was compared between patients with and without nocturnal polyuria according to each standard. A response was defined as a reduction in wet nights of >50%. RESULTS: The desmopressin treatment efficacy rate was 54% for polyuria and 67% for non-polyuria patients (P = 0.20), 45% for polyuria and 68% for non-polyuria patients (P = 0.08), 54% for polyuria and 59% for non-polyuria patients (P = 0.80), and 52% for polyuria and 61% for non-polyuria patients (P = 0.61), for the Akashi and Hoashi's, Hamano's, International Children's Continence Society and Rittig's standards, respectively. CONCLUSIONS: No difference was observed in the short-term clinical efficacy of desmopressin regardless of the presence of nocturnal polyuria. Thus, this might be a feasible treatment option for patients with nocturnal enuresis without nocturnal polyuria.

Impact of Long-Term Low Dose Antibiotic Prophylaxis on Gut Microbiota in Children.

PURPOSE: We evaluated the effect of long-term low dose antibiotic prophylaxis on children's gut microbiota. MATERIALS AND METHODS: We conducted 16S ribosomal RNA gene sequencing using stool samples from 35 patients younger than 3 years old (median age 5.2 months; male-to-female ratio 17:18) who underwent antibiotic treatment during the acute phase of febrile urinary tract infection. Samples were collected at 5 time points, ie before, during and at 1 to 2, 3 to 4, and 5 to 6 months after febrile urinary tract infection onset and antibiotic treatment. Continuous antibiotic prophylaxis using trimethoprim-sulfamethoxazole was initiated in 23 patients with grade III or higher vesicoureteral reflux and was not administered in 12 patients without reflux. RESULTS: Within 2 weeks after initiation of treatment for febrile urinary tract infection almost all enteric bacteria belonged to the order Lactobacillales, and gut microbiota diversity decreased compared to the pretreatment level (average Shannon index 2.9 before treatment, 1.4 during treatment). The diversity recovered within 1 to 2 months after febrile urinary tract infection onset in both groups. Diversity was maintained during the study period in both groups (p=0.43). A smaller proportion of gut microbiota component belonged to the order Enterobacteriales (p=0.002) in the antibiotic prophylaxis group. CONCLUSIONS: Our results revealed that patients receiving continuous antibiotic prophylaxis had normal gut microbiota diversity, indicating that the effect of trimethoprim-sulfamethoxazole on gut microbiota was insignificant. Furthermore, prophylaxis with trimethoprim-sulfamethoxazole might selectively suppress the growth of bacteria belonging to the order Enterobacteriales, such as Escherichia coli and Klebsiella species, which are the main causative bacteria of febrile urinary tract infections.

Optimal bacterial colony counts for the diagnosis of upper urinary tract infections in infants.

BACKGROUND: There are no consensus criteria for diagnosing upper urinary tract infections (UTI). Therefore, we conducted a study to assess whether bacterial colony counts of ≥ 103 CFU/ml are optimal for diagnosing upper UTIs among infants. METHODS: This retrospective observational study included 673 patients (<4 months of age) with urine samples obtained by catheterization for bacterial cultures. The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were obtained when cutoff values of 103, 104, and 105 CFU/ml were used for diagnosing upper UTIs. Upper UTI patients were divided based on cutoff values: Group A (103 CFU/ml), Group B (104 CFU/ml), and Group C (≥ 105 CFU/ml). RESULTS: Of the 197 positive (≥ 103 CFU/ml) patients, 92 were diagnosed with an upper UTI. These patients were divided into Group A (n = 23), Group B (n = 16), and Group C (n = 53). No significant differences were detected in terms of clinical findings, including the incidence of vesicoureteral reflex. When cutoff values of 103, 104, and 105 CFU/ml were used for diagnosing upper UTIs, the sensitivity/specificity percentages were 100/81.3, 75.0/95.9, and 57.6/97.5, and the PPVs/NPVs were 46.7/100, 75.0/95.9, and 79.1/93.4. CONCLUSION: Using ≥ 105 CFU/ml as a diagnostic threshold leads to approximately 40% of positive cases being missed. In contrast when ≥ 103 CFU/ml is used, all upper UTIs were identified. Therefore, bacterial colony counts of ≥ 103 CFU/ml should be considered the cutoff value for the diagnosis of upper UTIs in infants (< 4 months of age).

High daily salt intake had a negative impact on how well nocturnal enuresis treatment worked on children aged 7-10 years.

AIM: We investigated whether the daily salt intake of children with nocturnal enuresis influenced their response to 1-desamino-8-D-arginine vasopressin therapy. METHODS: This study comprised 129 children (67.4% boys) with a median age of 9.2 years (range 7.2-10.4) with monosymptomatic nocturnal enuresis who were seen at Kansai Medical University Hospital, Osaka, Japan, from 2013 to 2017. Urinary sodium concentrations were determined using a spot urine test, and the children were divided into appropriate (n = 55) and excessive salt intake (n = 74) groups based on Japanese Government guidelines. After a month of therapy, the treatment responses were compared for 39 and 50 children, respectively. RESULTS: There were no significant differences in the urea nitrogen-to-creatinine or calcium-to-creatinine ratios in the two groups. However, the excessive salt intake group showed a significantly reduced treatment response to the appropriate salt intake group. In addition, the excessive and appropriate salt intake groups showed median efficacy ratios of 8.2% and 21.8%, respectively, based on intention-to-treat analysis (P = 0.029) and 12.0% and 30.8% based on per-protocol analysis (P = 0.029). CONCLUSION: High daily salt intake significantly reduced the efficacy of ddavp therapy for nocturnal enuresis and consumption should be controlled during treatment.

Desmopressin response in nocturnal enuresis showing concentrated urine.

BACKGROUND: In Japan, the use of desmopressin (1-desamino-8-D-arginine vasopressin) is only recommended for nocturnal enuresis with unconcentrated first morning urine, which suggests a relative deficiency of antidiuretic hormone secretion during sleep. However, no such limitations have been described in a standardization document of the International Children's Continence Society. We aimed to determine whether desmopressin treatment induces any response in nocturnal enuresis with concentrated first morning urine. METHODS: Outpatients aged 6-15 years who exhibited monosymptomatic nocturnal enuresis were examined. Data were obtained from 41 treatment-naive patients (median age 9.7 years) with nocturnal enuresis, who received desmopressin as their first line of treatment. The patients were divided into two groups demonstrating unconcentrated (osmolality < 800 mOsm/L, Low-Osm group) and concentrated (osmolality ≥ 800 mOsm/L, High-Osm group) first morning urine, respectively; we compared the response to desmopressin treatment between the groups at 1 month after the administration or updosing of desmopressin; responses were defined as partial or complete according to the International Children's Continence Society standards. Mann-Whitney U-tests or Fisher's exact tests were used for analysis. RESULTS: The Low-Osm (median age 9.6 years) and High-Osm groups (median age 9.7 years) had 14 and 27 patients, respectively; the response rates to desmopressin treatment were 64.3% and 59.2%, respectively, indicating no significant differences (P = 0.99). CONCLUSION: Desmopressin treatment may be a feasible option for treating nocturnal enuresis with concentrated first morning urine.

Guidelines for the medical management of pediatric vesicoureteral reflux.

Urinary tract infection is a bacterial infection that commonly occurs in children. Vesicoureteral reflux is a major underlying precursor condition of urinary tract infection, and an important disorder in the field of pediatric urology. Vesicoureteral reflux is sometimes diagnosed postnatally in infants with fetal hydronephrosis diagnosed antenatally. Opinions vary regarding the diagnosis and treatment of vesicoureteral reflux, and diagnostic procedures remain debatable. In terms of medical interventions, options include either follow-up observation in the hope of possible spontaneous resolution of vesicoureteral reflux with growth/development or provision of continuous antibiotic prophylaxis based on patient characteristics (age, presence/absence of febrile urinary tract infection, lower urinary tract dysfunction and constipation). Furthermore, there are various surgical procedures with different indications and rationales. These guidelines, formulated and issued by the Japanese Society of Pediatric Urology to assist medical management of pediatric vesicoureteral reflux, cover the following: epidemiology, clinical practice algorithm for vesicoureteral reflux, syndromes (dysuria with vesicoureteral reflux, and bladder and rectal dysfunction with vesicoureteral reflux), diagnosis, treatment (medical and surgical), secondary vesicoureteral reflux, long-term prognosis and reflux nephropathy. They also provide the definition of bladder and bowel dysfunction, previously unavailable despite their close association with vesicoureteral reflux, and show the usefulness of diagnostic tests, continuous antibiotic prophylaxis and surgical intervention using site markings.

Effect of Delivery Mode and Nutrition on Gut Microbiota in Neonates.

BACKGROUND/AIMS: The mode of delivery (vaginal or cesarean section) and feeding type (breastfeeding or formula feeding) of neonates are considered the most influential factors in the development of gut microbiota. OBJECTIVES: This study investigated the effect of prebiotic-rich breast milk on overcoming gut microbiota dysbiosis. METHOD: Stool samples from 36 healthy Japanese neonates were obtained at 4 days and 1 month of age, and divided into 4 groups based on mode of delivery and feeding type. The gut microbiota composition and bacterial diversity were assessed using 16S rRNA sequencing. RESULTS: At 4 days old, vaginally delivered neonates had a significantly higher diversity of bacteria than those born by cesarean section. Bacteroidales and Enterobacteriales were overrepresented in vaginally delivered neonates (p = 0.0031 and p = 0.011), while Bacillales and Lactobacillales were overrepresented in caesarean section delivered neonates (p = 0.012 and p = 0.0016). However, there was little difference in bacterial diversity and bacterial relative abundance at 1 month of age between groups. CONCLUSIONS: Cesarean section delivery appeared to reduce the diversity of neonate gut microbiota, resulting in dysbiosis, but this improved to the equivalent level seen in vaginally delivered infants by 1 month of age. Breastfeeding, even for short periods, may therefore improve neonate gut dysbiosis.

Natural course of isolated mild congenital hydronephrosis: A 2-year prospective study at a single center in Japan.

OBJECTIVES: To determine a follow-up plan for mild congenital hydronephrosis in Japanese individuals. METHODS: Neonates at Kansai Medical University Hospital (Hirakata, Osaka, Japan) who were diagnosed with mild congenital hydronephrosis - defined as a Society for Fetal Urology grade 1 or 2 - at 1-month old by abdominal ultrasonography between 2014 and 2016 were enrolled. These patients were encouraged to undergo repeated abdominal ultrasonography for 2 years every 3 months to investigate the course of congenital hydronephrosis. RESULTS: Among 1009 neonates, congenital hydronephrosis was detected in 118 affected renal units of 100 (9.9%) patients. According to the definition of the Society for Fetal Urology, 118 affected renal units were graded as grade 1 in 87 (74%), grade 2 in 30 (25%), grade 3 in one (1%) and grade 4 in 0 units. Among them, 117 affected renal units of mild congenital hydronephrosis comprising grades 1 and 2 were subjected to ultrasonographic evaluation to monitor the natural course. The rates of resolution at 7, 10, 13, 16, 19, 22 and 25 months after birth in Society for Fetal Urology grades 1 and 2 cases were 60% and 8%, 77% and 19%, 90% and 32%, 92% and 40%, 95% and 52%, 96% and 56%, and 99% and 60%, respectively. CONCLUSIONS: Grade 1 congenital hydronephrosis does not need to be followed up, because it mostly shows spontaneous resolution by 2 years of follow up without any complications. However, ultrasonographic examinations at 1-year intervals for grade 2 congenital hydronephrosis are recommended to determine the subsequent follow-up plan of patients.

The Effect of Family Assistance to Wake Children with Monosymptomatic Enuresis in Alarm Therapy: A Pilot Study.

PURPOSE: Alarm therapy is widely used as first line treatment for nocturnal enuresis. However, some children do not wake when nocturnal urination activates the alarm. It is currently unclear whether waking the child when the alarm is activated improves the efficacy of alarm therapy. In this study we investigated the efficacy of alarm therapy for nocturnal enuresis when children do not wake in response to the sound and their parents do not wake them. MATERIALS AND METHODS: Detailed information regarding incontinence was retrospectively obtained from 78 of 112 patients who underwent alarm therapy between 2006 and 2016, and completed a questionnaire and a 14-day bladder diary. The enrolled patients were divided into 2 groups. In the family assisted group (44) the children were awakened by family members when the alarm sounded. In the alarm control group (34) the children were self-responsible for waking to the alarm. The groups were compared to investigate differences at 16 weeks after alarm therapy began. The efficacy rate was calculated using the International Children's Continence Society criteria. RESULTS: The efficacy was similar between the groups. Full response and partial response were observed in 36.4% and 20.5% of patients in the family assisted group, and 26.5% and 29.4% of patients in the alarm control group (p = 1.00), respectively. There was no significant difference in the percentage of children who woke spontaneously to the alarm in the 2 groups (56.7% and 64.0%, respectively). CONCLUSIONS: Family assisted alarm therapy and self-responsible alarm therapy are equally efficacious in the treatment of childhood nocturnal enuresis.

Gut Microbiota Dysbiosis in Children with Relapsing Idiopathic Nephrotic Syndrome.

BACKGROUND: While the etiology of idiopathic nephrotic syndrome (idiopathic nephrotic syndrome [INS]; characterized by repeated relapses and comorbid allergic conditions) remains unknown, recent evidence suggests that dysfunction in regulatory T cells (Tregs) plays an important role in the development of INS as well as allergic diseases. We hypothesized that dysbiosis involving decreased butyric acid-producing gut microbiota leads to defective induction and differentiation of peripherally induced Tregs, resulting in INS relapse. METHODS: Study subjects were 12 children with INS, 8 classified as relapsing (R group; median age: 3.0 years) and 4 as non-relapsing (NR group; median age: 4.3 years), and 11 healthy children (HC group; median age: 5.1 years) serving as normal controls. Measurement of microbiota was performed using 16S ribosomal RNA metagenomic analysis, and fecal butyric acid was measured using high performance liquid chromatography. Flow-cytometric analysis of Tregs and CD4-positive (CD4+) cells in peripheral blood was also performed. RESULTS: Metagenomic analysis of gut microbiota using feces showed that the proportion of butyric acid-producing bacteria was significantly lower in R (median 6.36%) than HC (median 18.84%; p = 0.0013), but no different between NR (median 16.71%) and HC (p = 0.29). Fecal organic acid analysis revealed significantly lower butyric acid quantities in R than HC (medians: 0.48 vs. 0.99 mg/g, p = 0.042). Circulating Tregs as a proportion of CD4+ cells were decreased in 75% of R and NR. CONCLUSION: Pediatric relapsing INS patients show gut microbiota dysbiosis, characterized by a decreased proportion of butyric acid-producing bacteria and lower fecal butyric acid quantities, concomitant with reduced circulatory Tregs.

Antiproteinuric effect of an endothelin-1 receptor antagonist in puromycin aminonucleoside-induced nephrosis in rat.

BackgroundThe pathogenesis of idiopathic nephrotic syndrome (INS) remains unclear, although recent studies suggest endothelin 1 (ET-1) and CD80 of podocytes are involved. We investigated the potential of antagonist to ET-1 receptor type A (ETRA) as therapeutic agent through the suppression of CD80 in a rat model of INS.MethodsPuromycin aminonucleoside (PAN) was injected to Wister rats to induce proteinuria: some were treated with ETRA antagonist and others were treated with 0.5% methylcellulose. Blood and tissue samples were collected. Quantitative PCR was used to determine the expression of Toll-like receptor-3 (TLR-3), nuclear factor-κB (NF-κB), CD80, talin, ETRA, and ET-1 in the kidney. To confirm the level of CD80 protein expression, immunofluorescence staining and western blot analysis of the renal tissue were performed.ResultsAmount of proteinuria in the treatment group was significantly lower than the other groups. The same-day body weight, serum creatinine values, and blood pressure were not significantly different. ETRA antagonist restores podocyte foot process effacement as well as the aberrant expression of TLR-3, nuclear factor-κB (NF-κB), and CD80 in PAN-injured kidneys.ConclusionsThe ETRA antagonist may be promising drug for INS as it showed an antiproteinuric effect. Its action was considered to be through suppression of CD80 expression on podocytes.

Urinary C-megalin for screening of renal scarring in children after febrile urinary tract infection.

BackgroundFebrile urinary tract infection (fUTI) in children may cause renal scarring. This study aimed to investigate the usefulness of urinary biomarkers for diagnosing renal scarring after fUTI.MethodsThirty-seven children (median age: 1.36 years, range: 0.52-12.17 years, 25 boys) with a history of fUTI, who underwent renal scintigraphy for 4 months or longer after the last episode of fUTI, were analyzed. A spot urine sample was obtained on the day of renal scintigraphy to measure levels of total protein, N-acetyl-ß-D-glucosaminidase (NAG), ß2-microglobulin (BMG), neutrophil gelatinase-associated lipocalin (NGAL), liver-type fatty acid binding protein (L-FABP), and C-megalin (full-length megalin). Results were corrected for urinary creatinine (Cr) and compared between the group with renal scarring (n=23) and that without scarring (n=14). Urinary levels of C-megalin were also measured in healthy control subjects.ResultsNo significant differences in total protein, NGAL, L-FABP, NAG, and BMG levels were found between the groups. However, C-megalin levels were significantly higher in the renal scarring group than in the non-renal scarring group and healthy controls (P<0.001). A cutoff value of 6.5 pmol/nmol of urinary C-megalin/Cr yielded 73.9% of specificity and 92.9% of sensitivity.ConclusionUrinary C-megalin is useful for diagnosing renal scarring caused by fUTI.

Risk factors for sodium valproate-induced renal tubular dysfunction.

OBJECTIVE: To explore the risk factors for the development of sodium valproate (VPA)-induced renal tubular dysfunction for early diagnosis and treatment. STUDY DESIGN: The subjects were selected from patients who were diagnosed with epilepsy and administered VPA. Blood and spot urine samples were collected and measured the concentration of VPA, the level of serum phosphorus, serum uric acid, serum free carnitine, serum cystatin-c, and urine ß2-microglobulin (BMG). Patients with urine BMG/creatinine levels above 219.2 were treated as renal proximal tubular dysfunction (RTD), with all others treated as non-RTD. RESULTS: Eighty-seven patients, 4-48 years, 53 men and 34 women, were studied. RTD group is 17 patients and non-RTD group is 70 patients. Univariate analyses revealed that the RTD patients were more likely to be bedridden, receiving enteral tube feeding, taking more anticonvulsants, and demonstrating significantly lower serum levels of free carnitine, uric acid, and phosphorus. Among them, bedridden, free serum carnitine, and phosphorus levels were associated with the development of RTD by multivariate analysis. CONCLUSIONS: Bedridden patients receiving VPA are susceptible to hypocarnitinemia, which can cause RTD and may lead to FS. Therefore, urinary BMG should be measured regularly in all patients receiving VPA to assess renal tubular function. An additional measurement of serum free carnitine level should be considered in patients who developed RTD. Supplementation of carnitine for those patients to prevent such complication deserves for further study.

Nocturnal enuresis and poor sleep quality.

BACKGROUND: Sleep disorders are strongly associated with childhood nocturnal enuresis (NE). In this study, we examined whether sleep disorders are present in children with NE, and whether NE is caused by sleeping disorders, or is simply comorbid. METHODS: We examined 14 children with monosymptomatic NE and 15 age-matched controls. Sleep disorders were assessed for ≥5 days using contactless biomotion sensors to detect breathing and body movements during at-home sleep. To assess sleep quality, we compared median sleep efficiency and the number of shallow sleep episodes between the groups. We also investigated the change in sleep quality after successful NE treatment in five children. RESULTS: Median sleep efficiency was significantly lower in the NE group (87.3%) than in the control group (93.4%; P < 0.001). The number of shallow sleep episodes per night was significantly higher in the NE group (5.11) than in the control group (1.50; P < 0.001). Neither sleep efficiency nor the number of shallow sleep episodes improved in the five children whose NE was successfully stopped after bedwetting-alarm therapy (P = 0.50 and 0.22, respectively). CONCLUSIONS: Sleep disorders are present in children with NE. Although there are insufficient data to conclude that sleep disorders are not the cause of NE, we suggest that they are comorbid because sleep disorders persisted even after NE was halted.

Decreased urinary excretion of the ectodomain form of megalin (A-megalin) in children with OCRL gene mutations.

BACKGROUND: The oculocerebrorenal syndrome of Lowe gene (OCRL) is located on chromosome Xq25-26 and encodes an inositol polyphosphate-5-phosphatase (OCRL-1). Mutations in this gene cause Lowe syndrome (LS) or type 2 Dent disease, of which low-molecular-weight (LMW) proteinuria is a characteristic feature. Megalin is considered to play an important role in the development of renal tubular proteinuria. Two forms of megalin are excreted into the urine: full-length megalin (C-megalin) and megalin ectodomain (A-megalin). We have explored the role of megalin in the development of LMW proteinuria in patients with OCRL mutations by determining urinary megalin fractions. METHODS: We measured A- and C-megalin in spot urine samples from five male patients with OCRL mutations (median age 9 years), using sandwich enzyme-linked immunosorbent assays, and adjusted the obtained values for excreted creatinine. The results were compared with those of 50 control subjects and one patient with type 1 Dent disease (T1D). RESULTS: All patients demonstrated normal levels of urinary C-megalin. However, patients with OCRL mutations or T1D showed abnormally low levels of urinary A-megalin, with the exception of one 5-year-old boy with LS, who was the youngest patient enrolled in the study. CONCLUSIONS: Decreased excretion of urinary A-megalin in four out of five patients with OCRL mutations suggests that LMW proteinuria may be caused by impaired megalin recycling within the proximal tubular cells. Homologous enzymes, similar to inositol polyphosphate-5-phosphatase B in mice, may help to compensate for defective OCRL-1 function during early childhood.