Common types of UC include: 1  proctosigmoiditis, which affects the rectum and lower portion of the colon. 2  left-sided colitis, which affects the left side of the colon beginning at the rectum.  total colitis, which affects the entire large intestine.
Vasovagal syncope. Vasovagal syncope is a sudden loss of consciousness mediated by the vagus nerve. It occurs when the vagus nerve is overreactive to certain triggers, such as the sight of blood or extreme emotional distress, and causes a sudden drop in blood pressure.
Vagus Nerve Stimulation. Sudden stimulation of a vagus nerve can produce what is called a vasovagal reflex, which consists of a sudden drop in blood pressure and a slowing of the heart rate. This reflex can be triggered by gastrointestinal illness or in response to pain, fright or sudden stress. Read about vasovagal syncope.