Endocrine Abstracts

Introduction: Hypocalcemia is a well known adverse reaction of phosphate supplements but rarely reported. We report a case of Infant presenting with hypocalcemic seizures after initiation of phosphate supplements.

Clinical case: A baby Girl was born at 34+4 weeks gestation. She was admitted in NNU for preterm care. The admission was complicated by severe Gastroesophageal reflux disease(confirmed by PH impedance study), anemia and sepsis. She was discharged home on Neocate LCP for a suspected cows milk protein allergy. Following discharge from the Neonatal unit, she developed faltering growth, recurrent chest infections, and rib fractures. Generalised osteopenia with radiological rickets as well as multiple long bone fractures was evident on the skeletal survey. Due to severe reflux and recurrent aspiration pneumonia, PEG was inserted. She was suspected to have a Metabolic bone disease with low phosphate (0.70), raised alkaline phosphatase (1043), normal calcium, Vitamin d (73) and low PTH (8). She was discharged home with 2 mmol/kg BD of phosphate supplement. Unexpectedly, she was admitted at the age of 9 months with a rigidity of extremities, vomiting, irritability and inconsolable cry with a fever. She developed generalized hypertonia with hypoxia needing oxygen. Anterior fontanelle was tense and bulging. She subsequently developed convulsions. Venous gas showed a low ionized calcium of 0.55. She was suspected to have Hypocalcemic tetany. Intravenous calcium replacement was given in form of 10% calcium gluconate followed by maintenance intravenous fluid with calcium supplement. She responded well to the infusion with reduction of tone. The diagnosis was confirmed with a low corrected calcium (1.32), normal magnesium and an elevated phosphate (2.77) on samples obtained prior to treatment. The parents confirmed that the first dose of Phosphate supplement was administered one hour prior to the episode via the PEG.

Conclusion: This case demonstrates the risk of Hypocalcemic tetany with phosphate administration. The first dose of phosphate should be considered to be administered in hospital under supervision particularly with a PEG in situ.