Symptoms usually start with a loss of alertness that can progress into complete loss of consciousness. As the herniation increases, the pupil of the eye on the same side of the head as the swelling will dilate, which means it gets bigger. Weakness on the opposite side of the body will usually follow. Breathing will become irregular. The pulse will start to slow down. Finally, both pupils become dilated, breathing becomes labored, and the pulse rate steadily decreases.