Sepsis is a severe infection in the body and bloodstream that can lead to shock, a reaction caused by lack of blood flow in the body.

What is going on in the body?

Sepsis can occur when a person has a severe infection. The infection may start in any part of the body, but usually starts with pneumonia (new-moan-ya), a serious inflammation in the lungs, or a urinary infection. Sepsis can also occur after an abdominal infection such as appendicitis (ah-pend-i-site-is). As the infection worsens, bacteria may enter the bloodstream. When this happens, toxins produced by the bacteria can affect the blood vessels. This causes severe low blood pressure. This is known as septic shock, and is a medical emergency. If not treated, septic shock will lead to death.

What are the causes and risks of the infection?

Septic shock can occur with any severe infection. It is more common with severe abdominal infections or lung infections such as pneumonia. People with an immune system that is not working are especially prone to septic shock. This includes people with AIDS or those getting cancer treatment. The very young and very old are also prone to sepsis.