Localized herpes zoster infection: a rare cause of syndrome of inappropriate secretion of antidiuretic hormone

Hyponatremia is the most common electrolyte abnormality observed in clinical practice and syndrome of inappropriate secretion of antidiuretic hormone (SIADH) is diagnosed in nearly 40% of the hospitalized hyponatremic patients. We present a case report of herpes zoster infection causing a severe hyponatremia/hypokalemia. This rare association between SIADH and varicella-zoster virus infection is described in only few case in the literature. In our case report, the associated hypokalemia was not related to the use of diuretics but, probably, dependent on the frank serum hyposmolality able to induce an aldosterone release.