To measure the effect of phototherapy on serum calcium level in neonates having hyperbilirubinemia in nicu of tertiary care hospital -an observational study

Jaundice is an important problem in the first week of life.it is a cause of concern for the physician and source of anxiety for the parents. High bilirubin level may be toxic to the developing central nervous system and may cause neurological impairment even in term newborns. Nearly 60% of term new born become visibly jaundiced in the first week of life . In most cases, it is benign and no intervention is required. Approximately 5-10% of them have clinically significant hyperbilirubinemia in whom the use of phototherapy becomes mandatory. Jaundice is attributable to physiological immaturity of neonates to handle increased bilirubin production. Visible jaundice usually appear between 24-72 hours of age. Basic pathophysiology of jaundice is same in term and preterm neonates,but premature babies are at a higher risk of developing hyperbilirubinemia. The commonly known side effect of the phototherapy are loose stool,hyperthermia,dehydration  fluid loss , skin burn, photo retinitis, low platelet count, increased red cell osmotic fragility, bronze baby syndrome, riboflavin deficiency and DNA damage. A lesser known side effect , but potential complication of phototherapy is hypocalcemia(hunter,2004). Neonatal hypocalcemia is defined as total serum calcium concentration of <7 mg/do or ionized calcium concentration of <4 mg/DL(<1mol/L). Ionized calcium is crucial for many biochemical processes , including blood coagulation, neuromuscular excitability, cell membrane integrity and function, and cellular enzymatic and secretory activity.

Hypocalcemia increases cellular permeability to sodium ions and increases cell membrane excitability. The sign are usually non specific like apnea , seizures, jitterness, increased extensor tone , tonus , hyperreflexia and stride( laryngospasm)

. phototherapy inhibits pineal secretion of melatonin which blocks the effect of cortisol on bone calcium.cortisol unchecked exerts a direct hypocalcemic effect and increases bone uptake of calcium as well.neonates requiring phototherapy are at a higher risk of developing hypocalcemia.

Although morbidity widely varies,serioud complications can arise from hypocalcemia.understanding the pathophysiology and treatment options for phototherapy induce hypocalcemia is important because significant morbidity and mortality are possible.