Thyroid Function and Serum Calcium Level in Children with Nephrotic Syndrome Attending a Tertiary Care Hospital in Kolkata, India: A Cross-sectional Study

Abstract

Introduction: Nephrotic Syndrome (NS) in children is a common renal disorder characterised by massive proteinuria, hypoalbuminaemia, and oedema. However, loss of thyroidbinding proteins and vitamin D metabolites in the urine may disrupt thyroid and calcium homeostasis. Aim: To evaluate thyroid function and serum calcium levels in children with NS attending a tertiary care hospital in Kolkata, India. Materials and Methods: The present cross-sectional study was conducted at the Department of Paediatrics in Chittaranjan Seva Sadan hospital of Obstetrics, Gynaecology and child health, Kolkata, India, from December 2022 to May 2024. Total 96 children aged 1-12 years diagnosed with NS (first episode or relapse) were enrolled in the study. Cases of thyroid disease, those on calcium supplementation within last 12 hours, blood/ albumin transfusion within last four month, known cases of liver disease, acute renal failure, acid-base disorders, or steroidresistant NS were excluded. Clinical data, thyroid profile {Triiodothyronine (T3), Thyroxine (T4), Thyroid-Stimulating Hormone (TSH)}, and serum calcium of those children who were included in the study were analysed. Continuous variables were expressed as mean±Standard Deviation (SD); categorical variables as percentages. Statistical comparisons were made using t-tests, Chi-square tests, and z-tests. In present study, significance was set at p-value <0.05. Results: In present study, out of 96 patients, 76 (79.2%) were male while 20(20.8%) were female. A total of 65 patients (67.7%) were below seven years of age while 31 patients (32.3%) were between 7-12 years of age. Mean age±SD was 58.4±34.3 months. Forty children (41.7%) had first episode, while 56 (58.3%) were relapsed cases. Hypothyroidism was present in 9(9.4%) overall, rising from 2 in 40 patients (5%) in first episodes to 3 in 4 patients (75%) in fifth episodes (p=0.0002). Mean serum calcium declined from 9.66 mg/dL in first episodes to 8.65 mg/dL by the fifth episode (p=0.0004), with hypocalcaemia observed in 75% of fifth episode cases. Conclusion: Thyroid dysfunction and hypocalcaemia are common metabolic complications in paediatric NS, particularly with recurrent episodes. Routine assessment of thyroid and calcium profiles is recommended to mitigate growth, metabolic, and bone health complications.