Causes, Risks, and Types of Gangrene in People with Diabetes

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Gangrene is a condition that involves the death and decay of tissue caused by a loss of its blood supply or by a bacterial infection. It usually affects the tissues furthest from your heart, such as, your hands and feet. It is typically treated by removing the dead tissue, often by amputation, as well as with antibiotics. People with diabetes are at increased risk of developing gangrene, especially if they have trouble controlling their blood sugar and have underlying health issues, such as atherosclerosis or peripheral arterial disease.

The Link Between Diabetes and Gangrene

People with diabetes are educated on the importance of blood sugar control and healthy foot care in order to prevent complications, such as gangrene. Elevated blood sugars can inhibit the bodies' ability to fight infection, which can prolong or prevent the ability to heal cuts and wounds. A person with diabetes, who sufferes from peripheral neuropathy (nerve damage to the extremities, such as hands and feet), or reduced circulation as a result of peripheral arterial disease (a condition in which one or more of the arteries supplying blood to the legs, arms, head or abdomen become blocked or partially blocked,) may not be able to feel a foot injury. For example, a person may stub his toe on the wall and not feel it. If unnoticed and coupled with elevated blood sugars ,overtime the wound won't heal properly and will likely become infected. An infection can increase the risk of gangrene. In addition to toes, feet, lower limbs, hands, and sometimes fingers can all become vulnerable to the conditions that may cause gangrene.

General Risk Factors for People with Diabetes

There are many different types of gangrene: dry, wet, gas, internal, Fournier's, and progressive bacterial synergistic gangrene. Of these, people with diabetes, who have damage to their blood vessels from high blood sugar and an impaired ability to fight infection are a higher risk of having dry and wet gangrene. In addition, atherosclerosis, peripheral neuropathy, peripheral arterial disease, and smoking increase the risk.

Symptoms of Gangrene

Symptoms of gangrene depend on the type. But generally, symptoms that affect the skin include: numbness in the affected part and it may also be cold to the touch. Discoloration from red to blue or black may be seen and there may be a foul-smelling discharge.

Dry Gangrene

Reduced blood flow or lack of circulation resulting from diabetes, cardiovascular problems, and smoking are the most common causes. It typically occurs in the hands, fingers, feet, and toes. Damage to the vessels inhibits oxygen and nutrient supply to the tissues, causing them to die and decay.

As the blood flow is choked off, tissues begin to die. It may develop slowly. At first, the area may become reddened but it gradually progresses to a brownish color. The skin may appear waxy. In the final stage, the affected body part will look withered and black in color.

General Causes:

An arterial blood clot, athersclerosis, and smoking are all caused of dry gangrene.

In People with Diabetes:

High blood sugar over time damages the blood vessels, which increases the risk of developing dry gangrene if you have diabetes.

Wet Gangrene

Wet gangrene, the most common type of gangrene, is a result from an untreated or poorly treated infections and can occur when a condition compromises blood flow.

General Causes:

General causes can include: burns, vascular trauma (for example, a knife wound, gunshot wound, traumatic accident).

In People with Diabetes:

In people with diabetes, wet gangrene can develop at the site of foot ulcers. where bacterial infections breed as the germs invade the tissues.

Having diabetes can impaire your immune system and make it more of a threat as you are more likely to be unable to fight off an infection in your feet or other tissues. As the infection causes swelling, it can cut off blood circulation and this leads to the tissues dying. It can progress rapidly. If it is not treated, there is a risk of developing septic shock, which can be deadly.

Gas Gangrene

This type of gangrene is most often caused by the Clostridium perfringens bacteria, which produces gas and toxins. It can cause gangrene anywhere in the body, sometimes deep in the organs. Gas gangrene can develop after surgery or trauma.

Risk Factors:

Risk factors for gas gangrene include diabetes, atherosclerosis, and colon cancer. It can develop suddenly and progress swiftly. This condition often requires emergency action to prevent shock, kidney failure, coma, and death. 

Internal Gangrene

Internal gangrene can affect your inner tissues and organs, without presenting symptoms on the skin or limbs. Common symptoms of internal gangrene include, pain, unexplained fever that lasts a long time, or low blood pressure. You may also experience confusion. This can occur, for example, when your intestines bulge through a weakened area of muscle in your abdomen (hernia) and become twisted.

Fournier's Gangrene

A very rare type of gangrene, Fournier's Gangrene, is more common in men then women, due to increase risk in infections on or near the genital area. It affects the genital area and is accompanied by symptoms of fever, pain, and swelling in the genitals or anal area, unpleasant odor coming from skin, dehydration, crackling sound when touching the affected area. The affected tissue can present purple, green, or even black in color. It can occur when there is an infection in the scrotum (which includes the testicles), penis, or perineum. The perineum is the area between the scrotum and anus for a man; or the area between the anus and vulva for a woman. The dead tissue can stretch to the thighs, stomach, and chest.

General Causes:

An infection, such as a urinary tract infection or bladder infection can cause this type of gangrene. It can also occur when someone undergoes a hysterectomy or presents with an abscesses.

In People with Diabetes:

People with diabetes are at increased risk of getting Fournier's gangrene, because elevated blood sugars complicate the bodies' ability to fight a urinary tract or bladder infection.

Progressive Bacterial Synergistic Gangrene

This is another very rare type of gangrene that is caused by skin lesions which develop a few weeks after surgery or an operation.

Gangrene Prevention

Adequate blood sugar control, regular check ups, and proper foot care can help to prevent gangrene in people with diabetes. Additionally, if you have diabetes and smoke, smoking cessation can decrease the risk of developing gangrene, as smoking inhibits blood flow and circulation.

A Word from Verywell

Gangrene can develop as a complication of diabetes when there is a lack of blood supply and poor blood sugar control to a specific are of the body. It is more likely to occur in the extremeties such as the feet. It's very important for people with diabetes to be aware of the different types of gangrene as well as the importance of healthy foot care and blood sugar control for prevention.

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Article Sources
  • Gas gangrene, MedlinePlus, U.S. National Library of Medicine.
  • Gangrene, MedlinePlus, U.S. National Library of Medicine.
  • Gangrene, Mayo Clinic Staff, Mayo Clinic.