A 59-year-old man was admitted with a diagnosis of acute cerebellar infarct. The next day his level of consciousness deteriorated (Glasgow Coma Score 5) and repeat computed tomography (CT) brain scan showed subtle signs of hydrocephalus. Following neurosurgical intervention, he recovered and is now walking with a frame and assistance. The CT changes of hydrocephalus were subtle and difficult to spot. Recognition of these signs of hydrocephalus and prompt neurosurgical intervention were lifesaving.