Polydipsia and hyponatremia in a woman with anorexia nervosa

Hyponatremia is infrequently reported in the constellation of metabolic abnormalities in patients with eating disorders. We sought to identify the etiology and describe the management of a patient with anorexia nervosa and hyponatremia.

We report the case of a 23-year-old woman with anorexia nervosa who suffered with severe hyponatremia.

The etiology of hyponatremia in this case, as in most patients with eating disorders, was multifactorial, encompassing both hypovolemic and euvolemic categories of hyponatremia. Multiple impairments in the ability to clear free water are responsible for a heightened risk for hyponatremia in patients with anorexia nervosa.

This case underscores the importance of careful scrutiny of fluid intake, an awareness of medications that lead to hyponatremia, and the need for regular monitoring of serum electrolytes, even in patients with anorexia nervosa, to allow for an early diagnosis and to assist in the formulation of an effective treatment and prevention strategy.