Determinants of Acute Kidney Injury in Children With Nephrotic Syndrome: A Prospective Observational Study.

Background Nephrotic syndrome (NS) is a common renal ailment among children, typically manifesting as a relapsing-remitting pattern. Most of the cases are managed on an outpatient basis, but a subset of patients experience complications, e.g., acute kidney injury (AKI). Although historically more prevalent in secondary NS, AKI is now occurring increasingly in children with idiopathic NS. However, the literature on AKI in this population consists of case reports and retrospective studies, particularly from India, so the study was planned to identify various risk factors that precipitate AKI in a child with NS. The secondary objective was to assess the hydration status of children having NS and its association with the development of AKI. Materials and methods This longitudinal study was conducted in the Department of Pediatrics at the All India Institute of Medical Sciences, Raipur, Chhattisgarh, from October 2021 to April 2023. Children of both genders and age groups between three months and 15 years, satisfying the International Society for Pediatric Neurosurgery 2021 guideline for the diagnosis of NS, were included in the study. Children having chronic kidney disease were excluded. Using the non-probability convenient sampling technique, 57 patients with NS were enrolled in the study. The patients without AKI were evaluated daily for the development of AKI using the Kidney Disease Improving Global Outcomes 2012 guideline until day 14 or discharge and followed up for six months. Records of those children who were admitted with AKI were reviewed for possible risk factors of AKI. Data was analyzed on Epi Info software enUS version 7.3.2 (Centers for Disease Control and Prevention, Atlanta, GA, USA). Categorical data were expressed as a percentage and/or 95% confidence interval (CI) of the estimate and compared using Chi-square or Fisher's exact test. A p-value ≤0.05 was considered statistically significant. The odds ratio (OR) for risk factors for AKI was determined using logistic regression. Results The mean age of the study subjects at the onset of the disease was 5.34 ± 3.66 years. The common presentations were edema (94.74%) and oliguria (80.7%). The majority (89.2%) showed a response to steroid therapy. About 56.14% of children developed AKI, and stages 2 and 3 AKI were more common, 37.5% each. About 53.12% and 46.88% of children developed pre-renal AKI and intrinsic AKI, respectively; 45.61% had hypertension at admission, with the majority having stage 1 hypertension (38.46%). Only six (10.5%) children had sickle cell trait, and all developed AKI during follow-up. Forty-two (73.68%) children had nephrotoxic drug exposure, with the most common drug being enalapril, followed by nephrotoxic antibiotics. Out of 10 children with AKI who underwent renal biopsy, focal segmental glomerulosclerosis was the most common entity (60%). The notable parameters that were found to have statistical significance for AKI were low eGFR at admission, hypertension, nephrotoxic drug exposure, inadequate water intake, fractional excretion of sodium (FeNa), and urine potassium index as markers of renal hypoperfusion, infections, steroid-resistant nephrotic syndrome, and significant glomerular lesions. Conclusion The present study demonstrates an association between traditional risk factors and the causation of AKI. However, high urine osmolality, raised urine K+ index, and FeNa suggestive of raised aldosterone levels had a significant association with AKI.