CAUSES OF DIABETIC GANGRENE
The role of blood
Blood contains two important components that the body’s cells require for life:
- oxygen
- nutrients, such as glucose, amino acids, and fatty acids
Without an uninterrupted supply of oxygen and nutrients, the body’s cells will lose the ability to function and they will die.
Blood also contains white blood cells and T-cells (âTâ stands for thymus, an organ in the body which helps to produce T-cells), both of which the body uses to help fight bacteria and viruses. Therefore, if the blood supply to a certain part of your body is cut off, not only will the tissue die but the dead tissue will have a far higher risk of becoming infected.
Gangrene and chronic disease
Any chronic (long-term) condition that can affect your blood vessels and arteries has the potential to cause gangrene, particularly if the condition is poorly managed. The blood vessels are already very narrow, so any damage or extra narrowing of the vessels can block the flow of blood to a part of the body.
Diabetic foot ulcers
Diabetic foot ulcers (an open wound or sore that develops on the skin) are one of the major causes of gangrene and amputation in people with diabetes. If you have diabetes, you may be more at risk of developing foot ulcers as a result of:
- reduced sensation
- reduced blood supply
These are described in more detail below.
Reduced sensation
The high blood sugar that is associated with diabetes can cause damage to the nerves (peripheral neuropathy), particularly in your feet. Once damaged, the nerves are unable to transmit sensations of pain to your brain.
Therefore, it is easy to damage or injure your foot by treading on something sharp, or to develop a blister due to ill-fitting shoes without actually realizing it. As a result of the lack of pain, you may continue walking without protecting the wound. This can make the wound worse and it may develop into an ulcer.
Reduced blood supply
High blood sugar can damage your blood vessels, causing the blood supply to your feet to become restricted. If the skin on your feet receives less blood, it will also receive a lower number of infection-fighting cells, which means that wounds will take longer to heal.
Therefore, the reduced sensation means that you are more likely to develop an ulcer, and the reduced blood supply means that the ulcer is more likely to become infected. The infection is likely to restrict the blood supply further, leading to gangrene.
If you have type 1 or type 2 diabetes, it is essential that you take extra care of your feet. You should get your feet checked regularly by a podiatrist (a medical professional, also known as a chiropodist, who specializes in foot care). See Gangrene -prevention for more information about this.
Gangrene and injury
Wet gangrene often develops as a result of a traumatic injury. The injury causes a sudden loss of blood to an area of your body, causing the tissue in that area to become infected with bacteria. It is estimated that around 50% of cases of wet gangrene are caused by serious traumatic injuries.
Common causes of wet gangrene can include:
- car accidents
- industrial accidents
- crush injuries
- burns
Gunshot wounds and frostbite are also causes of wet gangrene, but they are less common.
Gangrene and surgery
It is estimated that 40% of wet gangrene cases occur as a result of infection that develops during surgery. However, due to advances in surgical techniques and infection control, the chances of gangrene developing during surgery are very rare.
Gangrene and infection
Gangrene that results from infection, such as gas gangrene, or necrotising fasciitis, is very rare because the immune system usually prevents the spread of any harmful bacteria that may enter your body through a cut or other type of wound.
However, if your immune system is seriously weakened, minor infections may turn into serious infections. This can lead to gangrene developing.
Factors that are known to weaken the immune system, and increase the risk of developing infection that is associated gangrene include:
- chemotherapy
- radiotherapy
- HIV
- diabetes (both type 1 and type 2)
- chronic alcohol misuse
- intravenous drug abuse (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 still uncertain, a significant number of cases of necrotising fasciitis occur in young and otherwise healthy people.
