Comparison of calcium metabolism in different subgroups of nephrotic syndrome in children
Background: Children with nephrotic syndrome are at risk of altered calcium metabolism because of the disease per se as well
as steroid therapy even before fall in glomerular filtration rate (GFR). Objective: To compare the pattern of alteration in calcium
metabolism in different subgroups (infrequent relapser [IFR], frequent relapser or steroid-dependent nephrotic syndrome [FR/
SDNS], and patients in remission) of nephrotic syndrome in children. Methods: We conducted a cross-sectional study in the
Department of Pediatrics, PGIMS, Rohtak. Children between 1 and 8 years of age were divided into three groups, viz., IFR (Group I),
FR/SDNS (Group II), and patients in remission (Group III). Serum total calcium, ionized calcium, phosphate, parathormone (PTH),
albumin levels, and urinary calcium and phosphate were measured, and X-rays of both lower limbs were done. Results: 10 patients
in each group were compared. Serum total calcium, ionic calcium, and urinary calcium levels were decreased in patient with
nephrotic syndrome during active disease. No difference was noted in serum phosphate, urinary phosphate, and GFR in all the
three groups (p>0.05). Serum calcium and urinary calcium were significantly lower in Group II as compared to Group I (p<0.05),
whereas serum PTH levels were significantly higher in Group II as compared to Group I (p<0.05). None of the patients with
IFR and in remission had changes of osteopenia while 50% patients with FR/SDNS had features of osteopenia in their X-rays.
Conclusion: Hypocalcemia is a common finding in children with nephritic syndrome. These children especially those with FR or
SDNS should undergo careful monitoring of calcium, phosphorus, and PTH to prevent bone mineral disease.