Introduction: We present a rare case of postpartum central diabetes insipidus (DI) in a previously well 35 year old woman.
Case presentation: The pregnancy was uneventful until 40 weeks of gestation when she was admitted with prelabour rupture of foetal membranes. The delivery via caesarean section was complicated by intraoperative hypotension and severe postpartum haemorrhage. She developed polyuria on day 1 postpartum and central DI was confirmed biochemically on day 2 postpartum. There was no evidence of anterior pituitary hormone insufficiency, and she was able to lactate normally postpartum. MRI of the pituitary did not demonstrate any features to suggest Sheehan’s syndrome, pituitary apoplexy with underlying adenoma, or hypophysitis. The posterior pituitary bright spot could not be identified on T1-weighted images, which is suggestive of impaired arginine vasopressin (AVP) secretory capacity. The copeptin levels were low. This is suggestive of inadequate AVP secretion, which is consistent with central DI rather than transient gestational DI (where there is increased metabolism of AVP instead of inadequate secretion). The patient responded well to treatment with 1-deamino-8-D-arginine vasopressin, and she continues to require this medication at more than 15 weeks postpartum.
Conclusion: Abnormal blood flow to the posterior pituitary secondary to severe postpartum haemorrhage likely contributed to central DI by impairing AVP secretory capacity.