Last updated: 04 October 2011
Sepsis is a life-threatening illness caused by the body overreacting to an infection.
The body’s immune system goes into overdrive, setting off a series of reactions that can lead to widespread inflammation (swelling) and blood clotting in the body.
Sepsis occurs in three stages:
- Uncomplicated sepsis is caused by infections, such as flu or dental abscesses. It is very common and does not usually require hospital treatment.
- Severe sepsis occurs when the body’s response to infection has started to interfere with the function of vital organs, such as the heart, kidneys, lungs or liver.
- Septic shock occurs in severe cases of sepsis, when your blood pressure drops to a dangerously low level, preventing your vital organs from receiving enough oxygenated blood. See the Health A-Z topic on Septic shock for more information.
If it is not treated, sepsis can progress from uncomplicated sepsis to septic shock and can eventually lead to multiple organ failure and death.
How common is it?
It is estimated that there are over 30,000 cases of severe sepsis in the UK every year, and the number of cases seems to be rising.
If sepsis is detected early enough and has not yet affected the vital organs, it may be possible to treat the infection at home with a course of antibiotic tablets. Most people with uncomplicated sepsis make a full recovery.
Severe sepsis and septic shock are considered medical emergencies and normally require admission to an intensive care unit, where the body’s organs can be supported while the infection is treated.
Because of problems with vital organs, people with severe sepsis are likely to be very ill, and approximately 30-50% will die because of the condition.
Continue to next section: Symptoms of sepsis