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.
This sequence of events is called the vasovagal response, and it can cause you to feel weak, nauseous and even faint. In fact, it's the most common cause of fainting. When vasovagal response causes fainting, it is called vasovagal syncope. Vasovagal response is usually harmless.