Endocrine Abstracts

JOINT3795

Introduction: Adipsic diabetes insipidus (ADI) is a rare variant of central diabetes insipidus, characterized by hypotonic polyuria due to arginine-vasopressin deficiency and failure to generate the sensation of thirst in response to hypernatremia secondary to hypothalamic osmoreceptors damage. This predisposes to the development of significant hypernatremia, so its management is complex and requires strict water balance control and treatment with desmopressin.

Clinical case: 23-year-old male with neurofibromatosis type 1 and suprachiasmatic pilocytic astrocytoma treated with surgery, chemotherapy and proton therapy. After his last surgery in January 2021, he was diagnosed with ADI, panhypopituitarism and hypothalamic syndrome. For the treatment of ADI, he required high doses of desmopressin (minimum 600 mg/24 hours orally) and instructions were given to family members for its adjustment, as well as for the fluid intake control (minimum 2 liters/24 hours). He had basal natremias between 142 and 150 mmol/l, with frequent episodes of hypernatremia (around 1 to 4 per month) without trigger, up to >160 mmol/l, which were very difficult to control due to multiple factors (adipsia, neurological deterioration, refusal to eat, inability to record diuresis, …). For a period of less than 2 years, he required regular analytical measurements (at least 1 to 2 per month), several Home Hospitalization Unit visits for the administration of intravenous hypotonic solution, and as a last option, visits to the Emergency Department. In addition, he had 2 hospital admissions for this reason. In May 2023, a portable home blood analyzer (EPOC blood analysis system) was provided, properly validated for the determination of capillary sodium, and already used in pediatric ADI patients. Family members began to perform 1 or 2 capillary sodium measurements per week or when symptoms suggested hypernatremia, and instructions for adjusting desmopressin and water intake were reviewed. Given the earlier detection of elevated natremia, to date the patient has not required Home Hospitalization Unit assistance nor has he gone to the Emergency Department again for this sole reason, and switched to having lab tests only every 3 months. In addition, and also importantly, the quality of life of the patient and their relatives improved significantly.

Conclusion: Home capillary monitoring of natremia is an appropriate and cost-effective therapeutic measure for the treatment of ADI in both children and adults. For its proper use, it requires structured education for the patient and/or family members to adjust the treatment based on the results of capillary natremia.