Hypernatremic Hydrophobic Transient Adipsia Without Organic or Severe Psychiatric Disorder.

Context: Psychogenic adipsic hypernatremia is an exceedingly rare and life-threatening condition, occurring in those with severe psychiatric disorders. Its diagnosis requires exclusion of congenital or acquired hypothalamic pathologic entities. We present the case of a patient who experienced transient severe hypernatremia without evidence of brain pathologic features or known psychiatric disease. In our patient, the transient adipsic hypernatremia had resulted from an episode of mild depression that resolved spontaneously.

Case Description: A 46-year-old healthy woman who had had three recurrent admissions within 1 month had presented for evaluation of intractable nausea and vomiting with a history of a recent episode of a depressive mood change. Each admission had shown substantial hypernatremia (maximum plasma sodium, 166 mEq/L) accompanied by a strong aversion to consuming water. The findings from the diagnostic evaluation showed elevated serum osmolality and lower than expected urine osmolality (urine osmolality range, 474-501 mOsm/kg). This finding, along with an MRI scan showing the presence of a normal posterior pituitary bright spot, suggested that the osmoregulation of her thirst and arginine vasopressin (AVP) secretion were both defective during the attack. The patient was evaluated by psychiatry. Mild depression was diagnosed, and the patient started treatment with mirtazapine, which she only took for a few days. The patient's hypernatremia had completely recovered with resolution of her depression within 2 months.

Conclusion: A mild mood disorder can cause transient dysregulation of the thirst mechanism and AVP secretion through not yet identified mechanisms.