Gangrene - Causes of gangrene
- Introduction
- Symptoms of gangrene
- Causes of gangrene
- Diagnosing gangrene
- Treating gangrene
- Preventing gangrene
Gangrene can develop when the supply of blood to one or more areas of your body is interrupted.
This can happen as the result of an injury, an infection, or an underlying condition that affects your circulation.
Types of gangrene
There are several different types of gangrene, each with a different cause. The main types are:
- Dry gangrene – when the blood flow to an area of the body becomes blocked.
- Wet gangrene – caused by a combination of injury and a bacterial infection.
- Gas gangrene – where an infection develops deep inside the body and the bacteria responsible begin releasing gas.
- Necrotising fasciitis – caused by a serious bacterial infection that spreads quickly.
- Internal gangrene – when the blood flow to an internal organ, usually the intestines, gallbladder or appendix, becomes blocked.
Who is most at risk?
People most at risk of gangrene include those with an underlying health condition that can affect the blood vessels and arteries (particularly if it is poorly managed), and those with a weakened immune system.
Conditions affecting the blood vessels
Conditions that can affect the blood vessels and increase your risk of gangrene include:
- diabetes – a condition that causes a person's blood sugar level to become too high, which can result in damage to nerves and blood vessels (see below)
- atherosclerosis – where arteries narrow and become clogged with a fatty substance known as plaque
- peripheral arterial disease – where a build-up of fatty deposits in the arteries restricts blood supply to leg muscles
- Raynaud's phenomenon – where blood vessels in certain parts of the body, usually the fingers or toes, react abnormally to cold temperatures
As blood vessels are naturally narrow, any damage or extra narrowing has the potential to block blood flow to a part of the body and cause gangrene.
Diabetes
People with diabetes have an increased risk of developing gangrene because the high blood sugar levels associated with the condition can damage your nerves, particularly those in your feet, which can make it easy to injure yourself without realising.
High blood sugar can also damage your blood vessels, restricting the blood supply to your feet. Less blood means your feet will also receive fewer infection-fighting cells, so wounds will take longer to heal and are more likely to become infected.
Therefore, it is essential you take extra care of your feet if you have diabetes. See preventing gangrene for more information about this.
Injuries and surgery
You are also at an increased risk of gangrene if you experience a traumatic injury or serious damage to your skin and tissues, such as:
These injuries can cause a sudden loss of blood to an area of your body, and any open wounds can become infected with bacteria.
Some cases of gangrene occur as a result of infection that develops during surgery. However, advances in surgical techniques and infection control mean the chances of gangrene developing during surgery are small nowadays.
Weak immune system
If your immune system is seriously weakened, minor infections can become more serious and can lead to gangrene. A weak immune system can be caused by:
- chemotherapy or radiotherapy
- HIV
- diabetes
- chronic alcohol misuse
- injecting drugs, such as heroin
- malnutrition
- being over 60 (the older you are, the less efficient your immune system is)
- obesity
- kidney failure
However, for reasons that are unclear, some cases of gangrene occur in young and otherwise healthy people.
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