Signs and symptoms may include:

High blood pressure Irregular or slow pulse Severe headache Weakness Cardiac arrest (no pulse) Loss of consciousness, coma Loss of all brainstem reflexes (blinking, gagging, and pupils reacting to light) Respiratory arrest (no breathing) Wide (dilated) pupils and no movement in one or both eyes

Tests may include:

X-ray of the skull and neck CT scan of the head MRI scan of the head Blood tests if an abscess or a bleeding disorder is suspected