The authors studied 24 patients admitted to the neurointensive care unit because of clinical deterioration to drowsiness or stupor and midline shift after complete middle cerebral artery infarction (coMCAI) stroke. Fourteen (58%) experienced further deterioration and either underwent hemicraniectomy or refused surgery and died. These patients were significantly more likely to be female (72% vs 20%) and to have additional vascular territorial infarction (72% vs 0%) on initial CT. These features may help to identify patients at high risk for further deterioration after coMCAI.