Variable. From none to chronic headache, focal deficits, increased pressure on brain, seizure, dementia etc etc.
Emergency? Could well be an asymptomatic finding in pts on anti-coagulants, but could initially cause headaches, perhaps unilateral weakness, or leg weakness, and could expand with a catastrophic brain herniation (life threatening). In elderly, may see cognitive loss and confusion. Might contribute to seizures. Hospitalization with cafeful monitoring advised in most cases.