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 pathology. We present a patient who experienced transient severe hypernatremia without evidence of brain pathology or known psychiatric disease in whom the transient adipsic hypernatremia was due to an episode of mild depression resolving spontaneously.

CASE DESCRIPTION: A 46 year-old healthy woman who had three recurrent admissions within a month and presented for evaluation of intractable nausea, vomiting with a history of a recent episode of depressive mood change. Each admission showed significant hypernatremia (plasma sodium maximum =166 mEq/L) accompanied by a strong aversion to consuming water. Diagnostic work-up was significant for an elevated serum osmolality and lower than expected urine osmolality (urine osmolality range = 474-501 mOsm/Kg). This finding along with the MRI showing presence of a normal posterior pituitary bright spot suggested that the osmoregulation of her thirst and AVP secretion were both defective during the attack. Patient was evaluated by psychiatry, diagnosed with mild depression, and started on treatment with Mirtazapine, which patient only took for a few days. The patient's hypernatremia completely recovered with resolution of her depression within two months.

CONCLUSION: Mild mood disorder may cause transient dysregulation of the thirst mechanism and AVP secretion through not yet identified mechanisms.