Endocrine Abstracts

Background: Diabetes Insipidus (DI) is uncommon during pregnancy. It may predate pregnancy, be unmasked by pregnancy or arise de novo during pregnancy secondary to other pathology. We present a case of DI in pregnancy to highlight challenges in management.

Case Report: A 27-year-old lady at 21 weeks’ gestation, presented to A&E with worsening headache and confusion for three to five months. She was hemodynamically stable, had bitemporal hemianopia with no neurological deficit. Investigations showed anterior hypopituitarism, short Synacthen test confirmed secondary hypoadrenalism and MRI Pituitary showed macroadenoma with acute obstructive hydrocephalus. She was started on Hydrocortisone and Levothyroxine replacement and, underwent right frontal external ventricular drain (EVD) insertion. Three days later she had selective trans-sphenoidal pituitary adenomectomy. Post-operatively on Day 0 she had hypernatremia, serum sodium 152 mmol/l and polyuria. She was started on Desmopressin (DDAVP). Repeat biochemistry showed sodium 144 mmol/l, plasma osmolality 294 mmol/kg, urine osmolality 46 mmol/kg and Urine sodium<20 mEq/l, confirming DI. She needed close monitoring by endocrinology for dose titration of DDAVP. Post-operative MRI Pituitary showed improvement in obstructive hydrocephalus. She was discharged on Levothyroxine, Hydrocortisone and DDAVP replacement. At 34 weeks’ gestation she presented to A&E with pre-eclampsia and hyponatremia (sodium 125 m mmol/l). She underwent emergency LSCS and delivered a baby girl. Post-LSCS she had persistent hyponatremia (sodium 123 mmol/l, POsm 264 mmol/kg and UOsm 449 mmol/kg) and required lower doses of DDAVP.

Conclusion: Management of Cranial DI in Pregnancy is a challenge as placental cysteine aminopeptidase increases throughout pregnancy in parallel to increased clearance of arginine vasopressin (AVP). Fluid balance, serum sodium, plasma and urine osmolalities should be monitored closely during pregnancy, peripartum and postpartum periods to optimise DDAVP doses to achieve homeostasis. 1777 characters, 272 words.