The role of blood
Blood contains two important things that our cells require for life - oxygen and nutrients, such as glucose, amino acids, and fatty acids. Without an uninterrupted supply of both, the cells will lose the ability to function and die.
Blood also contains white blood cells and T-cells ('T' stands for thymus, an organ in the body which helps produce T-cells), both of which our body uses to fight bacteria and viruses. So, if the blood supply is cut off to a certain part of your body, not only will the tissue die, but the dead tissue will be at a far higher risk of infection.
Gangrene and chronic disease
Any chronic 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
One of the major causes of gangrene, and amputation, in people with diabetes, is diabetic foot ulcers. If you have diabetes, you may be more prone to foot ulcers for the two reasons listed below.
- Reduced sensation - the high blood sugar associated with diabetes can cause damage to the nerves (peripheral neuropathy) particularly in your feet. Once damaged, the nerves cannot transmit sensations of pain to your brain. Therefore, it is easy to damage, or injure, your foot by treading on something sharp, or develop a blister due to ill-fitting shoes, without actually realising it. Due to the lack of pain, you may carry on walking without protecting the wound. This can make the wound worsen, and it can develop into an ulcer.
- Reduced blood supply - high blood sugar can also damage the blood vessels, causing the supply of blood to your feet to become restricted. If the skin on your feet is receiving less blood, this means it also receives less infection-fighting cells, and so wounds can take longer to heal.
So, the reduced sensation means that you are more likely to develop an ulcer, while the reduced blood supply means that the ulcer is more likely to become infected. The infection further restricts the blood supply, and gangrene then develops.
If you have type 1 or type 2 diabetes, it is essential for you to take extra care of your feet, and you should get your feet checked by a podiatrist (a medical professional who specialises in the care of the feet, also known as a chiropodist) on a regular basis. See the 'prevention' section for more information about this.
Gangrene and injury
Wet gangrene can often develop as a result of a traumatic injury. The injury causes a sudden loss of blood to an area of your body, and the tissue in that area then becomes infected with bacteria. It is estimated that around 50% of cases of wet gangrene are caused by serious traumatic injuries.
Car accidents, industrial accidents, crush injuries and burns are common causes of wet gangrene. Gunshot wounds and frostbite are less common causes.
Gangrene and surgery
It is estimated that 40% of cases of wet gangrene are a result of infection that occurs during surgery. However, due to the advances in surgical techniques, and infection control, the chances of gangrene developing in this way are very rare.
