Adipsia

Adipsia is a rare disorder defined by a reduced or absent sense of thirst, resulting in inadequate fluid intake. Without sufficient drinking, individuals with adipsia are at risk of dehydration and electrolyte imbalance. It can occur on its own or as part of hypothalamic dysfunction that disrupts thirst regulation.

Most cases involve damage or dysfunction in hypothalamic regions responsible for detecting body fluid status, including osmoreceptors in areas such as the organum vasculosum of the lamina terminalis and nearby structures. Causes include traumatic brain injury, brain tumors, infections, congenital malformations, ischemia, inflammatory processes, and surgical injury. Adipsia may occur with other pituitary or hypothalamic disorders, and can be accompanied by hypodipsia, where thirst responsiveness is diminished but not completely absent.

Clinically, adipsia presents as reduced or absent drinking, signs of dehydration such as dry mucous membranes, reduced skin turgor, low urine output, tachycardia, and potential mental status changes in severe cases. In children, it can contribute to poor growth and weight loss. Diagnosis relies on history and physical examination, laboratory tests showing dehydration or electrolyte abnormalities, and neuroimaging to identify hypothalamic or pituitary causes.

Management centers on preventing dehydration and treating the underlying cause. This includes careful rehydration, electrolyte correction, regular monitoring of fluid intake, and strategies to ensure adequate hydration, which may involve caregiver-supported plans or supervised administration. Prognosis varies with the underlying etiology and the feasibility of restoring or compensating for impaired thirst regulation.