Intraoperative central diabetes insipidus in a postpartum patient during decompression of base of brain lesion: Missing out the diagnosis of Sheehan's syndrome?

A 35-year-old female presented with headache in the third week postpartum period following uneventful cesarean delivery. She had left sided ptosis, pain, and numbness over left face since third trimester. Post-delivery magnetic resonance imaging revealed invading left sphenoid sinus meningioma. She was planned for combined endonasal and pterional craniotomy. Her preoperative investigations including sodium, glucose, and liver functions were normal. Intraoperatively during endonasal phase a high urine output (UO) with rising sodium were noticed which continued with worsening sodium (156 mEq/L after 3 h). Desmopressin 1 mcg IV administered which normalized UO for the rest of surgical duration with trends of declining sodium (149 mEq/L at the end of procedure). Her postoperative MRI was normal however desmopressin could not be discontinued because of increasing sodium and UO without it. She was discharged on oral desmopressin, hydrocortisone and levothyroxine. On her follow-up 3.5 months later she had normal sodium and normal UO.