Renal impairment is one of the serious complication caused by hematopoietic stem cell transplantation (HSCT). Acute kidney injury (AKI) and chronic kidney disease (CKD) both could greatly affect prognosis and quality of life. In this study, we retrospectively analyzed the data of 72 pediatric patients with hematologic disease who underwent allogeneic HSCT to identify the incidence and risk factors of AKI and CKD after HSCT. The incidence of AKI was 59.7%, of which 4.7% required renal replacement therapy. The risk factor of AKI after HSCT was myeloablative conditioning (MAC). The cumulative incidence of CKD was 18.2%, of which 10% had stage 3. The risk factor of CKD was AKI after HSCT. In conclusion, AKI and CKD after HSCT were not uncommon. Early intervention of pediatric nephrologists, in cooperation with pediatric hematologists, would be recommended to prevent the onset and control the progression of AKI in patients with HSCT.

Background: After changing the urinary protein assay method from the pyrogallol red (PR) method to the benzethonium chloride (BC) method in 2019, the number of patients with a urinary protein-to-creatinine ratio (PCR) of 0.15  g/gCr or more increased. This study aimed to investigate the possible causes behind this increase. Methods: The subjects were elementary and junior high school students who had undergone urinalysis in our hospital at least once a year for 3 consecutive years from April 2017 and whose diagnoses were no abnormality or asymptomatic hematuria. The urinary PCR of the earliest morning samples were analyzed. Results: The participants were 74 patients (22 men and 52 women) with a median age of 12.3 years in 2019. The median urinary PCR was higher in 2019 using the BC method (0.14 g/gCr) than in 2017 and 2018 using the PR method (0.09 and 0.08 g/gCr, respectively). Conclusion: When the BC method was used to assess urinary protein, the PCR tended to be higher than that in the PR method. When evaluating the PCR, the urinary protein assay used should be noted.

Renal histology in patients with renal impairment associated with preterm and low birth weight infants is characterized by oligonephronia and focal segmental glomerulosclerosis (FSGS). Since its pathology is similar to that of mitochondrial (Mt) nephropathy, it is considered that an Mt disorder is involved in its pathogenesis. In this study, Staining with COX4 and mitochondrial transcription factor A (TFAM) in renal tissue were performed in 8 preterm cases with a low birth weight, and the relationship with the clinical features was examined. The mean urinary protein, Cr, and Cystatin-C were 0.67 g/gCr, 0.82 mg/dl, and 1.12 mg/L, respectively. In renal tissue, the average number of glomeruli was 3.2/mm², and in 5 cases, the glomeruli showed minimal change. FSGS was observed in 4 cases. Granular swollen epithelial cells suggesting an Mt disorder was observed in renal tubular epithelial cells in 7 cases, and staining for COX4 exhibited a mosaic pattern at the same site. TFAM expression was low in one case with a moderate tubular interstitial injury. Electron microscopy revealed swelling of the glomerular epithelial cells accompanied by an accumulation of abnormal Mt, in which cristae disappeared in 6 cases. This study suggested that an Mt abnormality may have been involved in renal injuries in low birth weight infants.

Non-steroidal anti-inflammatory drugs have been associated with hypertension in adults. We report an infant who developed hypertension after indomethacin use for patent ductus arteriosus. The patient was delivered at 31 weeksʼ gestation. Patent ductus arteriosus was detected on day 2. Indomethacin was given intravenously from day 2 to day 6. The ductus arteriosus was closed on day 7. On day 8, urine output decreased and serum creatinine increased. With fluid restriction, however, body weight remained the same from day 7 to day 14. Blood pressure increased to 82/41 mmHg on day 13 and became 90/58 mmHg on day 14 despite an increase in urine output. Cardiac ultrasonography suggested high afterload. With the use of nitroglycerin, blood pressure normalized on day 17. While non-steroidal anti-inflammatory druginduced hypertension in adults has been ascribed to renal vasoconstriction and resultant sodium retention, the major cause of hypertension in our case was thought to be high afterload due to increased peripheral vascular resistance presumably secondary to decreased synthesis of prostaglandin I₂.

There is currently a lack of an effective treatment for refractory ascites, other than general treatments such as restriction of water and salt and the use of diuretics. We report two childhood cancer patients with refractory ascites who received KM-CART that resulted in alleviation of their symptoms and improvement of their quality of life (QOL). Case 1: a 13-year-old male with desmoplastic small round cell tumor was unable to continue anti-tumor therapy due to refractory ascites. After a one-time use of KM-CART, the ascites disappeared and anti-tumor treatment was able to resume. Case 2: a 3-year-old boy with pancreatic acinar cell carcinoma was receiving palliative care, but his quality of life was significantly impaired from various symptoms caused by refractory ascites. He was provided with KM-CART four times every 2 weeks, and the symptoms were alleviated. For children that suffer from refractory ascites, this method is one of the significant options that should be considered.

We report a case of myocardial hypertrophy during treatment for nephrotic syndrome (NS). Initially, the hypertrophy was thought to be the effect of glucocorticoid (GC) because it was recovered after GC was discontinued. However, myocardial hypertrophy gradually progressed after GC was stopped. According to myocardial thickness over 13 mm and his family history of cardiomyopathy, he was diagnosed with hypertrophic cardiomyopathy. Myocardial hypertrophy was exacerbated again by the resumption of GC treatment, suggesting that GC could be deteriorating factors of myocardial thickening. GC is widely used for treatment for many diseases, including NS. In addition, hypertrophic cardiomyopathy is not a rare disease in Japan, which is 374 per 100,000 population. In administering GC, the cardiac assessment will be mandatory especially in cases with family history of myocardial disease.

Sulfamethoxazole-trimethoprim (ST) therapy inhibits renal tubular creatinine (Cr) secretion, thereby decreasing creatinine clearance (Ccr). The patient was a 9-year-old girl who was diagnosed with neuroblastoma originating from the right adrenal gland at 4 years of age and underwent multidisciplinary therapy. The patient had recurrent infections after the completion of therapy and was taking oral ST prophylactically. She developed drug-induced Fanconi syndrome in the course of the multidisciplinary therapy, and her renal function decreased after the completion of this treatment. Discrepancies between the estimated glomerular filtration rates (eGFR) based on Cr, cystatin C, and β₂-microglobulin were observed; thus, an inulin clearance test (Cin) was performed to accurately assess her renal function. Although GFR measured by Cin is normally lower than that measured by Ccr, the 2-h Ccr and Cin levels were similar(22.1 ml/min/1.73 m²). This presumably occurred as a result of ST therapy, which inhibited the secretion of Cr in the renal tubules to lower Ccr to a level close to that of Cin.

We experienced a 9-year-old boy who complained of abdominal pain and had severe hydronephrosis in the left kidney. Initially, the patient was scheduled nephrectomy because of his impaired left renal function, however, considering with his left renal parenchymal thickness, pyeloplasty was performed. Then, his renal function had improved. Even in severe hydronephrosis with impaired renal function, we should consider to rescue the kidney if the kidney have considerable parenchymal thickness.

The association of umbilical cord ulceration (UCU) and congenital upper intestinal (duodenal or jejunal) atresia has been reported since 1991. There have been multiple reports of life-threatening hemorrhage from UCU in patients with congenital upper intestinal atresia over the last two decades. However, there appears to be a gap in the dissemination of this knowledge.We report herein the case successfully treated with continuous hemodialysis in a neonate who presented acute kidney injury due to hemorrhage shock, and finally he was withdrawn from renal replacement therapy. In this case, renal tissue was also collected during surgery for congenital duodenal atresia. A kidney biopsy revealed severe>70% tubulointerstitial damage with glomerular immaturity. Acute renal injury due to UCU was found to be associated with circulatory failure. Although the prevention of sudden perinatal death is considered to be difficult, recognition of the clinical signs that typically precede hemorrhage and prepare the environment that can provide multidisciplinary care including renal replacement therapy may facilitate the early detection of this condition, thereby enabling the rescue of the affected fetuses. Further investigation is required to establish the management protocol.

A 12-year-old patient was admitted to our department due to the onset of renal colic symptoms. An ultrasound examination revealed right-sided hydronephrosis which had been caused by the presence of a ureteral stone. In addition, multiple stones in the calyx of both kidneys were observed. Cystinuria was diagnosed based on an increased cystine excretion level. Since renal scintigraphy of the right kidney showed a very low uptake and a renogram showed a severe impairment of the renal function, he was diagnosed with right-sided nephrolithiasis-associated acute kidney injury (AKI). He was advised to maintain a high fluid intake and was treated with potassium citrate in addition to tiopronin. 5 days later, the spontaneous passage of the stone was reported and the renal uptake was found to have recovered according to scintigraphy. However, 5 months later he had a recurrence of a right ureteral stone while showing right-sided AKI similar to the previous episode. The cystine level remained high during outpatient follow-up due to treatment non-adherence. Next, transurethral lithotomy was performed, and no recurrence has since been observed. In patients with cystinuria, recurrent obstructive uropathy are at high risk for developing chronic kidney disease (CKD). It is therefore necessary to educate patients about this disease, and monitor patients adequately to assess the effectiveness of treatment for preventing CKD.

We report a case of a 10-year-old boy with Goodpasture syndrome double-seropositive for anti-glomerular basement membrane (GBM) antibodies and anti-neutrophil cytoplasmic antibodies (ANCA). He was admitted to a hospital with 2 weeks of fatigue and loss of appetite. Blood tests revealed serum creatinine of 8.19 mg/dl and positive results for both serum anti-GBM antibodies and ANCA. Chest computed tomography (CT) showed diffuse ground-glass opacities (GGO) suggesting pulmonary hemorrhage. He was referred to our hospital and treated with six rounds of plasma exchange (PE) and three courses of methylprednisolone pulse therapy. Both serum anti-GBM antibodies and ANCA were undetectable, and the follow-up chest CT demonstrated the disappearance of GGO, but his renal function showed no improvement. Renal biopsy disclosed 98% sclerotic glomeruli and linear IgG depositions along the GBM. Nocturnal peritoneal dialysis was initiated, and prednisolone and mycophenolate mofetil were administered as maintenance therapy. Remissions occurred for 1 year after the initiation of treatment. Although he showed an end-stage kidney disease stage at admission, he was aggressively treated with PE and immunosuppressive therapy due to pulmonary hemorrhage. Owing to a relatively high risk of relapse, long-term immunosuppressive maintenance therapy should be considered for anti-GBM disease double-seropositive for anti-GBM antibodies and ANCA.

Diabetic ketoacidosis (DKA) is a frequent and serious complication of diabetes mellitus characterized by severe hyperglycemia, accumulation of ketone bodies, and metabolic acidosis. Metabolic acidosis during DKA consists of both high anion gap acidosis and normal anion gap acidosis. In addition, during DKA of type 1 diabetes, transient increase in urinary β₂-MG, urinary NAG, and aminoaciduria occur. A 5-year-old boy consulted a previous doctor for polydipsia, polyuria, and viciousness, and was admitted to the department of pediatrics at Fujita Health University Hospital. The patient was diagnosed as DKA with the onset of type 1A diabetes. After physiological saline loading, continuous intravenous injection of insulin was started, and at 24 hours after admission, he was withdrawn from DKA. Laboratory findings on admission revealed elevated urinary β₂-MG, metabolic acidosis, hypophosphatemia with low %TRP, and aminoaciduria. These were all alleviated with the treatment of DKA. Metabolic acidosis was considered to be a mixture of both high anion gap acidosis and normal anion gap acidosis. One month after onset, urinary β₂-MG, %TRP, and aminoaciduria were improved. Since transient Fanconi syndrome occurs during DKA, it is necessary to consider the effects of tubular dysfunction in the evaluation of hypophosphatemia and metabolic acidosis and the selection of treatment methods.

Comorbidities of congenital cystic kidney disease are various, and a definitive diagnosis is sometimes difficult. Mutations in the HNF1B gene found in congenital cystic kidney disease can cause developmental anomalies in multiple organs, including those of the genitourinary system, and produce various phenotypes. We experienced the case of a male, pre-adolescent patient with cystic kidney disease in whom the diagnosis of HNF1B was difficult to perform by ultrasonic examination alone and required the incidental discovery of the loss of the pancreatic tail. Non-kidney-specific complications should be considered in detail when examining cases of congenital cystic kidney disease.

We experienced a pediatric case in which left hydronephrosis and a giant ureter were found associated with macroscopic hematuria and Becker muscular dystrophy (BMD). The case was an 8 year-old boy. He visited our hospital with a first complaint of gross hematuria. Ultrasonography revealed left hydronephrosis (SFU classification Grade 2) and a giant ureter, and CT-urography revealed left renal ureteral transition stenosis. The patient was diagnosed with congenital anomalies of the kidney and urinary tract (CAKUT) without any external pressure from such as intestinal tract or tumor. Although he was naturally healthy and had no abnormal physical findings, he had a markedly high CPK level since the first visit. From the result of a genetic test (Multiplex Ligation dependent Probe Amplification: MLPA method), there were no abnormalities due to renal urinary tract injury, however, a dystrophin gene deletion was found in Exon 48, and BMD was diagnosed. To the best of our knowledge, there have been no previous reports of CAKUT associated with muscular dystrophy, and we report the relationship between the occurrence of renal ureter and skeletal muscle formation.

Atelosteogenesis is a chondrodysplasia characterized by severe short-limbed dwarfism with multi-joint dislocation and specific facial features caused by mutations in the gene encoding filamin B. We report a case of atelosteogenesis type III with a large bladder stone and proteinuria. He had hematuria at age 3 years, which was found to be due to kidney stones and hypercalciuria. Hypercalciuria was thought to be due to excessive intake of protein and sodium in addition to immobilization from the original disease. Kidney stones formed, moved to the bladder after the patient became able to sit up. The bladder stone became enlarged due to urinary tract infection. Proteinuria was also detected, which gradually worsened with a glomerular pattern. Surgical removal of the bladder stone and the kidney biopsy were performed concomitantly. The stone consisted of calcium phosphate and magnesium ammonium phosphate. The kidney biopsy showed minor abnormalities. Postural proteinuria was considered to be the cause since he kept sitting position during the day. As he started to move by shuffling, proteinuria decreased. Bladder stone and proteinuria should be born in mind when seeing patients assuming a long-term sitting position.

Introduction: We report the case of a patient tested for occult blood by school urinalysis screening but eventually diagnosed as having end-stage renal failure with antineutrophil cytoplasmic antibody (ANCA)-associated nephritis. Case: A 14-year-old girl with Williams syndrome without cardiac complications was diagnosed as having occult blood in urine by school urinalysis screening for the first time at 1 year 6 months prior. Owing to her recent fever, she was found to have oliguria, edema, and renal impairment and was admitted to a hospital. Laboratory data showed the following values: urinary protein, 4+; occult blood in urine, 3+; blood urea nitrogen, 129 mg/dl; and creatinine, 9.1 mg/dl. As she had acute renal failure caused by a rapidly progressive glomerulonephritis, urgent dialysis was started. Pulmonary hemorrhage occurred, and she was myeloperoxidase-ANCA positive. On the basis of the renal biopsy findings of pauci-immune-type crescentic glomerulonephritis, she was diagnosed as having microscopic polyangiitis. Steroid pulse therapy, plasma exchange, and rituximab administration reduced the alveolar hemorrhage and turned the ANCA to negative. Nevertheless, her renal function was not restored with the introduction of maintenance dialysis. Discussion: Therefore, discussion is needed on the appropriate period to measure ANCA in the case of abnormalities in urinalysis.