Tissue anywhere in the body can die for various reason. Usually this is a result of a bacterial infection or lack of blood supply. When this body tissue dies, it is referred to as gangrene. Most of the time gangrene occurs in the feet and lower legs but it can occur anywhere in or on the body. Untreated gangrene, especially when there is a bacterial infection, can be life threatening.
Types of Gangrene
Groups of cells are referred to as tissue and collections of tissues make up the various organs and parts of the body. Every cell in the body needs a constant supply of oxygen and nutrients. Any interruption to the blood supply means that the cells do not receive the vital oxgen and nutrients to sustain life. Similarly if microorganisms like bacteria enter the tissue and the body’s defenses cannot counteract it, the health of the infected tissue is compromised. Eventually tissue death will occur if there is no prompt medical treatment.
Dry gangrene is usually caused by narrowed blood vessels (atherosclerosis) and diabetes. It develops slowly. The affected site typically appears dry. There is always a risk of the area becoming infected and then dry gangrene may become wet gangrene.
Wet gangrene arises with a bacterial infection and develops rapidly. This is more likely to occur with injury to the area which then becomes infected. It is more commonly seen in diabetics who injure their toe or foot and with other injuries like frostbite and severe burns.
Gas gangrene occurs when the tissue under the skin is infected and dies. It is more likely to arise with an injury or surgery where gas-producing bacterium like Clostridium perfringens gains entry to deeper-lying tissue like muscle while the blood supply to these areas are compromised.
Internal gangrene is when there is tissue death within an internal organ. It mainly occurs when the blood supply to an organ or part of an organ is cut off. Apart from atherosclerosis and blood clots, arteries that become compressed may also release to internal gangrene. This can be seen in conditions like bowel strangulation. It can be life threatening if left untreated.
Read more on bowel strangulation.
Fournier’s gangrene is where there is tissue death in the genital area. It occurs with infections of the genitalia or urinary tract. This type of gangrene is more common among men but can also affect women.
Progressive bacterial synergistic gangrene
Also known as Meleney’s gangrene, it arise about 1 to 2 weeks after surgery. Overall, progressive bacterial synergistic gangrene is rare.
How To Spot Gangrene
While any person can develop gangrene after certain types of injuries or with an infection, diabetics in particular have to cautious. The combination of poor blood supply, impaired sensory perception and weakened immune system that occurs with diabetes increases the risk of gangrene, especially in the feet and lower legs. Therefore diabetics need to inspect their feet and lower legs on a regular basis for any sign of possible gangrene. This is more important for long term diabetics and especially those with poorly managed diabetes.
Read more on diabetic foot.
Most of the signs and symptoms discussed below relate to dry and wet gangrene as well as gas gangrene. Symptoms may vary with the other types of gangrene. It is important to note that some forms of gangrene, like gas gangrene in the early stages and internal gangrene, may not have a typical presentation as discussed below. In fact internal gangrene symptoms can be misleading and it may not be immediately suspected. Therefore the signs and symptoms alone should not be relied upon as an indicator of all types of gangrene.
Brown, Purple or Black Skin
Discoloration of the skin is most evident from the outset in dry and wet gangrene. However, it may eventually become apparent in gas gangrene as the condition progresses. The skin discoloration in dry gangrene can vary from brown to purplish-blue and eventually black in color. It is not uncommon for there to be reddish or even pale discoloration of the skin in early stages of drug gangene as well as in wet gangrene and gas gangrene.
Spongy, Blistering and Bubbling
Swelling of the skin may also be seen particularly with wet gangrene and as gas gangrene progresses. On its own, swelling is not a conclusive sign of gangrene as it can occur for other reasons, especially in the feet and lower legs. Sometimes the swelling may not as obvious and the area feels a bit spongy compared to surrounding tissue.
There may also be blistering of the skin where there are tiny fluid-filled bumps. In gas gangrene there is a bubbly appearance of the skin and a crackling sound may be heard when pressing on the skin over the affected area. In some types of gangrene, the affected are may become hard.
Numbness to Pain
Despite gangrene being a sign of severe damage, pain may not necessarily be present. Diabetics in particular may not experience pain with injuries and infections that even precede the onset of gangrene. This is a result fo diabetic neuropathy, where the nerves are damaged due to diabetes. Sometimes there is numbness with gangrene while in other cases the pain may be very severe.
A foul-smelling discharge (pus) that is oozing from a sore is another possible sign of gangrene. This is due to the decomposition of tissue as well as the presence of bacteria. This odor is described as fetid and other terms that may also be used is “rotting”. Although all signs of gangrene should be investigated by a doctor, foul-smelling pus is of particular concern as this can indicate a bacterial infection that may rapidly spread and cause septicemia.
Fever and Malaise
Fever may not always be present in gangrene. It is a non-specific sign meaning that the presence of a fever does not indicate a specific condition. Gangrene may not be immediately suspected in internal gangrene due to non-specific symptoms like fever and pain. Malaise is a general feeling of being unwell. As is the case with fever, it is a non-specific sign but may occur with gangrene and worsen as the condition progresses.