ESPE Abstracts

Introduction: Adipsic diabetes insipidus (ADI) arises from the destruction of both antidiuretic hormone (ADH) neurons and osmoreceptors in the hypothalamus. This condition is characterized by polyuria, loss of thirst sensation and hypernatremia. Managing serum sodium levels is particularly challenging, often resulting in fluctuations in serum sodium and osmolality, which elevate the risk of morbidity and mortality. This report presents the clinical follow-up of a case of ADI following craniopharyngioma surgery.

Case: A three-year-old male patient, born at term with birth weight of 3000 grams, presented to the emergency department with intermittent headaches persisting for two months, followed by an afebrile convulsion. His height was 95.5 cm(-1.66 SDS), body weight 15.4 kg(-0.49 SDS), and head circumference 50 cm(-0.67 SDS). Physical examination revealed no abnormalities. Cranial CT imaging identified a well-defined, lobulated cystic mass with peripheral calcifications, measuring 28x33x48 mm. The patient underwent surgical intervention for the mass and histopathological examination confirmed craniopharyngioma. Postoperatively, the patient developed polyuria and hypernatremia, despite having normal pituitary function preoperatively. The patient, serum Na: 164 mmol/L, serum osmolarity: 338.9 mOsm/kg, urine osmolarity: 135 mOsm/kg, ADH: 7.2 pmol/L (<13), was evaluated as central DI and desmopressin treatment was started. Additionally, the patient developed central hypothyroidism postoperatively and was commenced on L-thyroxine therapy. Recurrent hyponatremia was noted from the 4th postoperative day, raising the suspicion of inappropriate ADH syndrome. This led to the discontinuation of desmopressin therapy following fluid restriction. Although serum sodium levels normalized with intravenous fluid restriction, polyuria and hypernatremia recurred from the 9th postoperative day. The patient exhibited resistant hypernatremia with levels reaching up to 183 mmol/L under desmopressin therapy. The absence of thirst despite significant hypernatremia led to a diagnosis of ADI. Throughout the follow-up period, the patient’s serum sodium levels fluctuated between 122-183 mmol/L. Hypernatremia was managed by targeting the patient's weight, administering 2x22.5 mcg(3 mcg/kg/day) of oral desmopressin and ensuring a daily fluid intake (at least 750 cc/m²/day(8x60 cc)), aim ing to maintain serum sodium levels at 140 mmol/L. The family was educated on adjusting the child's fluid intake based on daily weight measurements.

Conclusion: The management of patients with adipsic diabetes insipidus requires close monitoring of body weight and fluid intake, in conjunction with desmopressin therapy. These factors are particularly critical in cases of craniopharyngioma-associated resistant hypernatremia.

Keywords: Adipsic Diabetes Insipidus, Craniopharyngioma, Resistant Hypernatremia