ESPE Abstracts

Introduction: We describe a 4 month old term infant of a vitamin D deficient mother who presented with bronchopneumonia and cardiomegaly needed respiratory support. Despite resolution of bronchopneumonia he had persistent normal anion gap metabolic acidosis. In the process of investigating into symptomatic hypocalcaemia revealed rickets with 25-hydroxy-vitamin D (Vit D) deficiency and high parathyroid hormone (PTH) which led to distal renal tubular acidosis. Biochemical, radiological resolution and disappearance of cardiomegaly were demonstrated with adequate vitamin D treatment.

Case report: A 4month old previously well baby boy presented with a 3 day history of cough, fever and tachypnea. He was diagnosed to have bronchopneumonia and cardiomegaly needed ventilation. Echocardiogram revealed left ventricular dilatation. He had normal growth with exclusively breasting. Despite the settlement of respiratory infection his tachypnea persisted. He developed carpopedal spasms. His blood gases revealed normal anion gap metabolic acidosis. Chest x-ray revealed osteopenia and rachitic rosary. Serum ionized calcium was 1.37 mmol/l (normal range 2.2-2.7mmol/L) with low phosphate levels 0.57mmol/l (1.45-2.16) and high alkaline phosphate (ALP) level of 1230IU/L. From the same serum sample PTH level was very high 891.4pg/ml (7.5-53.5) and Vit D level came as 28nmol/l (<30nmol/l deficient). He was acutely managed with IV 10% Calcium gluconate followed by oral calcitriol 250 ng twice daily and titrated according to corrected calcium. The baby was started on Vit -D3, 2000IU/day with calcium carbonate 250mg twice daily. Further clinical evaluation large anterior fontanel, widening of wrists were noted. X-ray of wrist showed classical metaphysical widening, fraying, splaying and cupping. The diagnosis of vitamin D deficient rickets was made. However normal anion gap metabolic acidosis persisted (PH-7.223, HCO3-12 mmol/l, CO2-21 mmHg). urinary PH was 6.5 and urine electrolytes were normal. USS KUB didn’t show evidence of nephrocalcinosis. Mother’s Vit D level was 48nmol/l, which was insufficient with normal calcium and alkaline phosphatase levels and started on Calcium and vitamin D supplements. After 3 months of therapy, treatment response has been demonstrated with normalization of biochemical markers, blood gas and normal cardiac status, with vitamin D3 treatment and calcium supplementation.

Conclusion: This is a rare manifestation of nutritional rickets in an infant due to maternal vitamin D deficiency with cardiomegaly and PTH induced distal renal tubular acidosis. Vitamin D deficiency is possible as a result of poor maternal stores. Prompt management with Vit D and calcium supplementation will help to achieve quick clinical recovery.