Post-obstructive diuresis (POD) is a potentially serious complication following surgical correction of ureteropelvic junction obstruction (UPJO) in pediatric patients. Characterized by excessive urine output after decompression of a chronically obstructed renal system, POD may result in significant fluid and electrolyte imbalance. While physiologic POD is transient, pathologic forms require careful management. This study aimed to determine clinical and demographic risk factors associated with POD following UPJO surgery in a pediatric population. We conducted a retrospective cross-sectional study of pediatric patients undergoing UPJO correction at two tertiary centers in Mashhad, Iran, from July 1, 2020, to July 1, 2021. Data were extracted from hospital records, including age, sex, hydronephrosis grade, presence of renal tubular acidosis (RTA), serum creatinine, and anemia status. POD was defined as urine output >4 mL/kg/h for three consecutive hours postoperatively. Statistical analyses included Chi-square tests and independent t-tests; p < 0.05 was considered significant. A total of 360 patients were included (65 % male; mean age: 62.2 ± 18.3 months). POD occurred in 22 patients (6.1 %). Patients with POD were significantly younger (mean age: 50.3 ± 10.7 months vs. 63.2 ± 18.6 months; p < 0.001) and more frequently presented with Grade 4 hydronephrosis (81.8 % vs. 45.6 %; p = 0.001). No significant associations were found between POD and sex (p = 0.435), RTA (p = 0.683), serum creatinine levels (p = 0.509), or anemia (p = 0.347). Younger age and severe hydronephrosis were significantly associated with increased risk of POD after surgical correction of UPJO. These findings underscore the importance of close postoperative monitoring in high-risk pediatric populations. Prospective studies with standardized POD criteria are needed to validate these predictors and optimize perioperative care.

Recurrent hypokalaemia and iron-deficiency anaemia in a young adult should prompt evaluation for uncommon renal and gastrointestinal disorders. The coexistence of distal renal tubular acidosis (dRTA), cryptogenic multifocal ulcerous stenosing enteritis (CMUSE), and superior mesenteric artery (SMA) syndrome is exceptionally rare. A woman in her 30s presented in 2019 with profound hypokalaemia and cardiac arrest secondary to possible dRTA. Biochemistry confirmed non-anion gap metabolic acidosis with inappropriate renal potassium loss. Despite supplementation, she later developed severe iron-deficiency anaemia and underwent small-bowel resection for capsule retention; histology confirmed CMUSE. Subsequent weight loss and malnutrition led to radiological evidence of SMA syndrome. She experienced recurrent admissions for electrolyte crises, requiring long-term intravenous replacement via a peripherally inserted central catheter and multidisciplinary input from nephrology, gastroenterology, and endocrinology. This case illustrates the cumulative burden and interdependence of multiple rare disorders within one patient, emphasising the need for persistent diagnostic review, multidisciplinary care, and awareness of atypical disease combinations in young adults with refractory electrolyte and nutritional abnormalities.

Primary distal renal tubular acidosis (dRTA) is a rare inherited renal tubular disorder having a significant impact on growth and kidney function. Data on molecular genetics and long-term outcomes of primary dRTA, especially for newer genotypes, are limited. 63 probands with a clinical diagnosis of dRTA underwent molecular genetic testing, specifically including SLC4A1, ATP6V1B1, ATP6V0A4, WDR72, and FOXI1. Genotype-phenotype characteristics and long-term outcomes were studied in this observational cohort study. Diagnostic yield of genetic testing was 58.7%. Genotype positivity was associated with severe clinical and biochemical disease. SLC4A1 (38.5%) was the most common genotype, followed by WDR72 (13.5%) and ATP6V1B1 (11.5%). SLC4A1: p.Ala858Asp (32.7%) was the exclusive biallelic variant detected (likely founder variant in the region). Five (9.6%) had variants of unknown significance. Notable features at initial presentation were delayed diagnosis (median 17 months), frequent failure to thrive [44 (78.6%)], rickets [40 (71.4%)], and hypokalaemic paralysis [11 (19.6%)]. Mean [(standard deviation (SD)] follow-up duration was 14.8 (11.7) years. 30 (53.6%) were > 18 years of age at last clinical visit. Long-term follow-up was characterised by poor final height [mean (SD score): -3.0 (2.2)], persistent bone deformities [19 (33.9%)], and decreased eGFR [mean (SD): 89.4 (26.1) ml/min/1.73m2]. The biallelic SLC4A1: p.Ala858Asp variant was characteristically associated with increased osmotic fragility of red blood cells, manifesting as haemolytic anaemia. ATP6V1B1, ATP6V0A4 and FOXI1 variants were associated with sensorineural hearing deficit. All probands with WDR72 variants manifested amelogenesis imperfecta. We report 13 novel genetic variants in primary dRTA and the fourth proband with a rare FOXI1 variant. Primary dRTA in Asian Indians is a genetically diverse disease, and is characterised by delayed diagnosis, severe growth failure, bone deformities, and decreased kidney function in the long term. Findings from this study highlight the regional diversity and expand genotype-phenotype correlations in primary dRTA.

The primary defect in distal renal tubular acidosis (dRTA) is impaired H+ ion secretion in the distal nephron, resulting in a normal anion gap metabolic acidosis. The solute carrier family 4-member 1 (SLC4A1) gene encodes the erythroid and renal anion exchanger 1 (AE1) protein for chloride-bicarbonate exchange. Mutations in the gene can result in hereditary dRTA, red blood cell membrane defect, and hemolytic anemia. Chronic granulomatous disease (CGD) is a rare primary immunodeficiency syndrome caused by NADPH oxidase deficiency, leading to impaired neutrophil and phagocyte function, and thus predisposing the patient to multiple bacterial infections. Melioidosis is a rare infection caused by Burkholderia pseudomallei and is often linked to CGD. Here we present an interesting case of an 8-year-old girl with melioidosis secondary to CGD. Also, she had nephrocalcinosis, metabolic acidosis, hypercalciuria, and anemia. The simultaneous presence of distal RTA (Pathogenic homozygous SLC4A1 mutation on whole exome sequencing) and CGD has not been reported previously and reiterates the importance of detailed clinical evaluation combined with investigations for the long-term management of such complex cases.

Wilson disease (WD) is an autosomal recessive disorder in which mutations in ATP7B lead to excessive copper deposition in the liver, brain, eyes, kidneys, and other organs. Patients with WD can present with hepatic dysfunction, neurological symptoms, rare hemolytic anemia, and renal tubular acidosis. A 27-year-old female patient with liver cirrhosis and maturity-onset diabetes of the young was found to have normal serum ceruloplasmin (25.9, 20-60 mg/dL) and copper levels (17.81, 12.6-23.6 μmol/L). Liver biopsy revealed severe lobular hepatitis (multiple lobular/large necroses), early cirrhosis with a small amount of copper deposits, hepatocyte lipidosis, balloon-like changes, Mallory bodies, and glycogenated hepatocyte nuclei. Genetic analysis of ATP7B exon found 2 variants (c.2333G>T, p. Arg778Leu) in exon 8 and (c.3209C>G, p. Pro1070Arg) in exon 14. Based on the available results, the Leipzig score was 7 and the diagnosis of WD can be confirmed. A late Kayser-Fleischer corneal rings test came back positive. The patient's clinical management included d-penicillamine and insulin. At approximately 6 months of follow-up, the patient's liver function was well controlled and the cirrhosis did not progress or have decompensated events. Although WD is treatable, its early detection is challenging. Genetic testing and liver pathology are sometimes necessary for the diagnosis of WD. This case underscores the consideration of WD in the differential diagnosis of patients with liver cirrhosis. Normal ceruloplasmin levels do not rule out WD.