Hypodipsic hypernatremia and diabetes insipidus following anterior communicating artery aneurysm clipping: diagnostic and therapeutic challenges in the amnestic rehabilitation patient

Hypodipsic hypernatremia (HH) represents a pathological increase in serum s odium due to a lack of thirst and defect in hypothalamic osmoreceptors. Whi le 15% of patients with HH have a vascular aetiology, few cases have been d escribed. Moreover, the presence of such abnormalities in the amnestic pati ent can have particularly threatening implications, as HH tends to recur un less the patient complies with a regimen of water intake. This study report s the case of a 46-year-old male admitted for rehabilitation of functional deficits following subarachnoid haemorrhage (SAH), with clipping of an ante rior communicating artery (ACoA) aneurysm. Clinical examination was remarka ble for profound short-term memory loss and inability to retain new informa tion. Blood chemistry on admission showed a serum sodium level of 160 mEq/L , increasing to 167 mEq/L the following day. The patient denied thirst, and showed no clinical signs of dehydration. Neuroendocrine evaluation reveale d diabetes insipidus (DI) and HH. Treatment initially included DDAVP and in travenous hydration, later supplemented with chlorpropramide. Stabilization of serum sodium and osmolality did not ensue until the treatment regimen i ncluded hydrochlorothiazide and supervision of enforced fluid intake. Endoc rine abnormalities may be encountered among patients with vascular lesions adjacent to the hypothalamus. Rehabilitation interventions include establis hing a structured medication regimen with fluid administration in the amnes tic patient with hypothalamic dysfunction.