Recurrent Vomiting due to Severe Hyponatremic-Hypertensive Syndrome in an Elderly Patient.

Hyponatremic-hypertensive syndrome (HHS) is a rare disorder, particularly in adults. A 76-year-old woman presented with vomiting and severe hyponatremia. The patient had been hospitalized four times over the past four years due to hyponatremia and recurrent vomiting. On admission, magnetic resonance angiography revealed left renal artery stenosis, which led to a diagnosis of HHS. Treatment with enalapril followed by tolvaptan improved the patient's condition, without the need for renal artery angioplasty. HHS should therefore be considered in patients with hyponatremia, hypertension, or recurrent vomiting. In addition to angiotensin-converting enzyme inhibitors and renal artery angioplasty, tolvaptan may also be a new effective treatment option for HHS.