Endocrine Abstracts

Hypopituitarism is a condition of inadequate or absent production of the anterior pituitary hormones (http://emedicine.medscape.com/article/923789-overview). We report a case of newborn with hypocortisolaemia in whom starting hydrocortisone unveiled diabetes insipidus and panhypopituitarism.

Case presentation: A term baby girl born by normal delivery to Caucasian parents presented with poor feeding, hypothermia and hypoglycemia with blood glucose of 1.8 mmol/l. She was treated for suspected sepsis. On day 2, she was noted to be hyponatremic (129 mmol/l), hyperkalemic (6.6 mmol/l), and the 17-OH progesterone was normal. She had hypoglycemia screen that revealed low cortisol of 46 nmol/l. Hydrocortisone was started after failed short Synacthen test (cortisol of <30 nmol/l at 0 min and 90 nmol/l at 60 min). Hypoglycemia resolved but she was noticed to have developed hypernatremia (147 mmol/l) and polyuria (5.8 ml/kg per h). Paired plasma and urine osmolality revealed underlying diabetes insipidus that was possibly obscured by concomitant cortisol deficiency. She was also noted to be hypothyroid and an ophthalmic review showed optic atrophy.

Discussion: Hypopituitarism is common but congenital form is rare.¹ Congenital hypopituitarism may be the result of complications around delivery, or may be the result of insufficient development (hypoplasia) of the gland, sometimes in the context of specific genetic abnormalities like mutations in HESX1 and SOX2.² Neonates with congenital hypopituitarism may present with nonspecific symptoms. As cortisol is necessary to excrete a free water load, cortisol deficiency may obscure diabetes insipidus.³

Conclusion: Hypopituatisrism can be an evolving condition with other hormone deficiencies becoming evident over a period of time. This case highlights the importance of looking for posterior pituitary dysfunction while managing hypocortisolaemia.

References: 1. Gaurav Atreja et al. Congenital hypopituitarism and renal failure. Indian J Endocrinol Metab 2011 15(Supp l3) S253–S254.

2. McNay DE, Turton JP, Kelberman D et al. HESX1 mutations are an uncommon cause of septo-optic dysplasia and hypopituitarism. J Clin Endocrinol Metab 2006 92(2) 691–697.

3. Rajaratnam S et al. Hydrocortisone dose and postoperative diabetes insipidus in patients undergoing transsphenoidal pituitary surgery: a prospective randomized controlled study. Br J Neurosurg 2003 17(5) 437–442 (Medline).