Digitalis delirium in elderly patients.

Case histories of four elderly patients with central nervous system signs of digitalis toxicity were reviewed. Evidence of toxicity included lethargy, depression which was not present previously, confusion, restlessness, emotional instability, hyperventilation, and vertigo. Vomiting developed four days after the onset of the mental changes. No cardiac arrhythmias were observed. Digoxin serum levels ranged between 4.2 and 7.0 ng/ml. Serum potassium values were within normal limits. Three of the four patients recovered with a return of their mental status to the pretoxic state. The fourth case was fatal. At autopsy long-standing myocardial ischemia was the only significant finding.