An Uncommon Cause of Choreoathetosis.

Choreoathetosis is an uncommon presentation in the emergency department setting. The differential diagnosis is broad and includes life-threatening as well as benign causes. Lethal etiologies include metabolic derangements such as hyponatremia as in the case presented here. Hypotonic hyponatremia is the most common electrolyte imbalance and can result from 1 of 2 broad categories of dysregulation: excess free-water intake and solute depletion. Here we describe a case of hypotonic hyponatremia due to a less common route of excess free-water intake. Choreoathetosis as a presenting symptom of hyponatremia is described in case reports. We present a case of a 77-year-old Thai woman who presented to the ED with complaints of weakness, mild headache, confusion, vomiting, and choreoathetoid movements for 1 day. She endorsed chronic, worsening constipation and decreased appetite. She was found to be severely hyponatremic with a serum level of 114 mEq/L requiring admission to the intensive care unit (ICU) for emergent electrolyte correction. She denied any diuretic use or excess oral water or alcohol intake. The etiology was unclear until a careful history was taken, whereupon it was revealed that she had been self-administering tap-water enemas excessively for relief of constipation. Choreoathetosis resolved with careful electrolyte correction. A home-administered tap-water enema leading to hyponatremia and choreoathetosis is a subtle presentation that underscores the importance of careful social history-taking, especially when dealing with vague or non-specific symptoms. We review some more common causes of hyponatremia and discuss its initial management.