"Organic brain syndrome" secondary to 5-fluorouracil toxicity.

A 68-year-old woman, who was treated with 5-fluorouracil (5-FU) intravenous therapy weekly for variable periods following hemicolectomy for adenocarcinoma of the cecum, had at least two well-described episodes of mental confusion, disorientation, and deterioration, in the absence of cerebellar tract signs. The sensorium cleared after cessation of 5-FU, only to deteriorate following readministration of the drug. She was thought to have organic brain syndrome during her most recent mental relapse. Her mental status has now been intact for more than one year since her last exposure to 5-FU. This is believed to be the third patient who has shown mental changes which could be attributable to 5-FU toxicity. Since 5-FU is the most frequently used chemotherapy for the treatment of colonic cancer, it is important that this form of toxicity be recognized lest subject patients be judged to have irreversible organic brain syndrome or metastatic carcinoma.