Triphasic Response And More - Post-Operative Diabetes Insipidus in A Patient With Sphenoid Meningioma: A Case Report

Research Objectives To describe the management of water homeostasis fluctuations and difficulties associated with rehabilitating a patient with post-surgical central diabetes insipidus who manifested a rare triphasic response. Design Case report. Setting Tertiary hospital. Participants 47-year-old female office worker. Interventions The patient was initially diagnosed with a left sphenoid wing meningioma and underwent elective excision. Her post-operative sodium levels fluctuated wildly, corresponding to central diabetes insipidus (DI), followed by a triphasic response comprising antidiuresis due to SIADH and subsequent DI which required longer-term desmopressin therapy. This case was notable for extreme serum sodium swings of 30mEq in a day requiring urgent reversal and titration. Main Outcome Measures Serum sodium and osmolality; Montreal Cognitive Assessment; Ambulation distance; Functional Independence Measure. Results In contrast with published reports of pituitary manipulation-induced DI, this case illustrates the possibility of brain surgery in areas remote to the pituitary to be capable of inducing the rare triphasic DI pattern. This patient developed psychiatric disturbances that may have led to inconsistent technique in self-administration of intranasal desmopressin, in addition to inappropriate polydipsia. With stabilization of her sodium fluctuations, the patient was able to continue with rehabilitation for her other deficits of diplopia, gait dysfunction, and cognition. No new neurocognitive sequelae arose from the water balance disorder and she was discharged well to independent living. Her sodium levels were stable at follow-up 1 and 3 months later, with good treatment compliance to long-term desmopressin. Conclusions Water balance disorders post-neurosurgery can be rapid and drastic, and a triphasic response of post-surgical DI can arise from seemingly-minor pituitary manipulation and even remote sphenoid meningioma excision. Post-treatment monitoring of fluid status in such patients remains crucial and physiatrists should maintain sensitivity to psychiatric disturbances and changes in mentation, if any. Author(s) Disclosures None.