A 72-year-old woman on dialysis acutely developed disturbed consciousness and severe hypertension. Head computed tomography (CT) demonstrated only ventriculomegaly without bleeding. Her consciousness level further deteriorated after dialysis using heparin, and subsequent head CT revealed a new, minor intraventricular hemorrhage. Hemorrhage-associated hydrocephalus was diagnosed, and the installation of a ventriculoperitoneal shunt resulted in good recovery. The patient might have experienced minor repeated bleeding and developed latent post-hemorrhagic hydrocephalus. Even minor bleeding could cause acute exacerbation of hydrocephalus; therefore, clinicians should be alert to hydrocephalus when a dialysis patient develops disturbed consciousness without any evidence of stroke on head CT.