What happened, in summary

A 54-year-old woman with stage IV gastric cancer developed sudden difficulty speaking 1 day after starting FLOT chemotherapy. The regimen included 5-fluorouracil, leucovorin, oxaliplatin, and docetaxel, with 5-fluorouracil given over 48 hours. She had no limb weakness, chest pain, shortness of breath, headache, vision changes, or palpitations. Her speech improved spontaneously within hours.

During the admission, she had chemotherapy-related vomiting and a temporary drop in blood pressure to 80/50 mm Hg with a heart rate of 120 beats per minute. Testing also found severe new weakness of the heart muscle without blocked coronary arteries. The timing and rapid reversibility supported 5-fluorouracil-related cardiotoxicity.

She was managed conservatively and started carvedilol and lisinopril, then discharged with a wearable defibrillator. At follow-up 1 week later, her ejection fraction had fully recovered to 65%. Because of the suspected 5-fluorouracil reaction, her subsequent gastric-cancer chemotherapy was changed to carboplatin and paclitaxel.