What is gangrene? – Types, Causes and Symptoms

What is Gangrene?

Gangrene is a serious condition in which the blood supply from the circulatory system to certain parts of the tissue stops and the tissue eventually decays and dies. This often happens in the extremities (the parts farthest from the heart) like hands and legs (especially in the toes and fingers) . In very few cases, this can happen to internal organs like the gallbladder which is called internal gangrene. The part affected by it usually appears greenish-black in color. 

Blood supply to the tissues usually stops when the individual has any underlying condition contributing to it like diabetes or atherosclerosis (a disease that hardens the arteries and obstructs the blood flow to the vessels). In some cases infection, smoking and conditions like Raynaud’s disease can also be the cause of this dangerous condition. 

Gangrene when left unnoticed or untreated early is fatal. It can even lead to amputation when the condition worsens. 

In rare cases, gangrene can spread through the body and can cause the person to go into temporary shock. Shock can lead to death in due course if immediate treatment is not considered.

What are the types?

1. Dry Gangrene – this type happens when blood flow to certain parts of the body is affected due to poor circulatory systems and the tissues in those areas dry and die. It normally affects the hands and feet and is slow to develop . The tissue may change colour and seem brown or black. This type doesn’t usually become infected. However, in rare cases, if it becomes infected, it may lead to wet gangrene. People with diseases related to blood vessels (vascular diseases), diabetes and autoimmune diseases are likely to get dry gangrene.

2. Wet Gangrene – Gangrene is said to be wet if there is a bacterial infection in the affected tissue. Common features are blistering, swelling and a wet appearance.

Wet gangrene usually happens when there is an injury in any part of the body, wherein the tissues get crushed or squeezed and eventually die or after a severe burn or frostbite. These dead tissues lead to infection, resulting in wet gangrene and the infection from a wet gangrene quickly spreads throughout the body. Often, it occurs in those with diabetes who unknowingly injure a toe or foot. This is fatal and is more dangerous.

3. Gas gangrene – This is a rare type of gangrene that is deadly and which normally happens when there is an infection deep inside muscle tissues. If you have gas gangrene, your skin’s surface may appear normal at first. The skin may become pale and turn into grey or purplish-red as the condition gets worse

The skin may also appear bubbly and may make a crackling sound when it is pressed because of the gas within the tissue. A bacterium called Clostridium perfringens causes Gas gangrene infection. The infection can be due to any trauma or injury. A toxin releasing bacteria called clostridia ejects dangerous toxins along with gas, which gets accumulated in the tissue. The skin around the affected region turns pale or gray, showing the sign of gangrene formation. Gas gangrene is very dangerous if immediate treatment is not considered.

4. Fournier’s gangrene – This is a type of gangrene that affects men more than women. Fournier’s gangrene happens when there is an infection in the genital area. This is also a rare type of gangrene, however, needs to be treated at the earliest. As long as the infection stays in the genitals it is curable, but if the infection spreads into the bloodstream, a condition called sepsis happens, which will lead to malfunctioning of the organs in the body and could be fatal.

5. Progressive bacterial synergistic gangrene or Meleney’s gangrene – This is again a rare type of gangrene that causes lesions on the skin around the affected spot, which usually happens due to any injury or minor trauma or may be after a surgery. This type of gangrene usually takes time to develop (1-2 weeks after the injury or a surgery). When treated at the proper time, it can be brought into control. 

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What causes Gangrene?

The causes depend on the type. They can be as follows:

Causes of Dry Gangrene

• Vascular problems – damaged blood vessels are the reason for this condition. The poor health of arteries and veins in legs and toes leads to the complication when the person has severe ailments like diabetes, peripheral arterial disease and high blood pressure. Severe burns, scalds and cold – chemical reactions on the skin, heat, cold, or even frostbite can cause dry gangrene to form. This may later develop into wet gangrene. 
• Raynaud’s disease – This rarely causes dry gangrene, when there is weakened blood circulation to the fingers and toes. 
• Diabetes – Diabetes is one of the main reasons for many serious health complications including gangrene. People with diabetes usually have fluctuated sugar levels in the blood due to the loss of insulin. These imbalanced blood sugar levels affect the blood vessels and nerves, which in turn obstruct the supply of blood and essential nutrients to the extremities.

Causes of Wet Gangrene

• Injury – deep wounds due to crushing or squeezing can lead to wet gangrene, as bacteria can cause infection on these wounds and in turn the tissues in the affected region decay and die. 
• Immune deficiency – A weakened immune system makes way for infections to easily develop in the organs, leading to wet gangrene formation. Immune system may be damaged due to many reasons like HIV, diabetes, chemotherapy or radiotherapy, frequent consumption of alcohol or any drugs, smoking, etc.  

What are the risk factors?

Some of the risk factors are:

• Surgery or severe injury: Anything that causes trauma to the skin and the underlying tissue, including frostbite or an injury, raises the risk of developing gangrene, especially if there’s an underlying condition which affects the blood flow to the injured area.
• Diabetes: If you are diabetic, your body does not produce enough insulin, a hormone the helps cells take up blood sugar, or is resistant to insulin. High blood sugar levels may damage blood vessels eventually, interrupting or reducing blood flow to a part of the body.
• Blood vessel disease: Narrowed or hardened arteries (atherosclerosis) and blood clots can also block the blood flow to an area of the body.
• Obesity. Often obesity accompanies vascular disease and diabetes. However, the extra weight stress alone can also compress the arteries, causing reduced blood flow and increasing the risk of infection including poor wound healing.
• Smoking: Smokers are at a higher risk of gangrene.
• Medicines or drugs that are injected: In some rare occasions, some medicines and injectable illegal drugs may cause infection with bacteria that may lead to gangrene 
• Immunosuppression: If you are human immunodeficiency virus (HIV) positive or if you are undergoing radiation therapy or chemotherapy, the ability of your body to fight off an infection is impaired.
• COVID-19 Complications: There are some reports of people infected with dry gangrene in their toes and fingers after having COVID-19-related coagulopathy (blood clotting problems). However, more research is needed to confirm this link.

What are the symptoms experienced?

The symptoms of gangrene depend on the causes. Some of the common symptoms for all types of gangrene are:

• Discoloration of skin – skin turns pale and cold
• No feeling felt on the affected area – numbness
• Infrequent pain felt on the affected area
• Redness and swelling are seen on the skin around the affected area

When the gangrene is infected, the symptoms may include:

• Chills
• Persistent fever with high temperature
• Dizziness
• breathing issues
• Rise in heartbeat
• Bleeding and pus formation in the sores and blisters – often a discharge is seen
• Discomfort or severe pain in the gangrenous area
• Crackling feeling on the affected area – this happens in the case of  gas gangrene
• Discoloration of skin around the affected area (the color change may be from red to brown and to purple to black
• Low blood pressure, mental confusion – when the gangrene is internal
• Sudden shock

How can this condition be prevented?

Gangrene can be prevented in the following ways:

• Checking blood glucose levels – People who have issues in the circulatory system due to their condition, but particularly due to diabetes need to take care of their blood sugar levels. It is always important to keep diabetes under control in order to prevent gangrene.
• Watching out on injuries – keeping an eye on the extremities for any injuries and getting them treated at the earliest is essential, so as to not have them develop gangrene in the long run. 
• Quitting smoking and avoiding alcohol consumption is an important way to prevent gangrene and many other related health problems
• Exercising regularly helps with improving the circulatory system and people with diabetes must exercise on a daily basis to keep the disease under control and to avoid many other related serious health problems including gangrene.
• Help prevent infections: Wash open wounds with water and mild soap, and keep them clean and dry until they get healed.
• Pay attention when the temperature drops: Frostbitten skin can cause gangrene as frostbite reduces circulation of blood in an affected area.