ESPE Abstracts

Background: Hypernatraemia in a neonate can be common, and is usually due to high rates of insensible water loss and high urine output and subsequent dehydration. This is commonly resolved with supplementation of feeds.

Case presentation: We present a preterm baby born at 35 weeks gestation who was born in good condition, did not require ventilation or intensive care support. The only support required was for feeding and thermoregulation. In the second week of life was noted to have weight loss and hypernatraemia thought to be hypernatraemic dehydration, therefore feed volumes were increased by bottle and nasogastric tube. Despite feed supplementation hypernatraemia persisted. Further investigation with paired osmolalities was suggestive of diabetes insipidus. Test dose of desmopressin showed weight gain and normalisation of investigations. Initial further endocrine tests were normal and patient was discharged home on desmopressin. Regular follow-up showed reduced height velocity at 3 years of age. Endocrine testing was repeated and showed inadequate response to glucagon stimulation test, therefore partial hypopituitarism was diagnosed. The patient was regularly reviewed in the joint endocrine clinic by tertiary Paediatric Endocrinologist and a course of GH treatment was initiated.

Conclusion: Hypernatraemic dehydration not responsive to rehydration should be further investigated and diabetes insipidus considered. This case illustrates the importance of continuous monitoring and regular endocrine evaluation in identifying development of additional pituitary dysfunction.