It is the dying or dead body tissue that occurs as a result of a bacterial infection or inadequate blood flow. It tends to affect the extremities – the fingers, toes and limbs. My maternal grandmother’s loss of both limbs in one year started with the development of gangrene in a couple of toes.
- Dry gangrene – Characterised by dry and shrivelled skin, it ranges in colour from brown to purplish-blue to black. Usually, dry gangrene develops slowly. It occurs most commonly in people who have a blood vessel disease.
- Wet gangrene – It is referred to as “wet” if there’s a bacterial infection in the affected tissue. Swelling, blistering and a wet appearance are common features, which can develop after a severe burn, frostbite or injury. People with diabetes who unknowingly injure a toe or foot tend to be at risk.
- Gas gangrene –Typically affects deep muscle tissue. Initially the surface of your skin may appear normal. As the condition progresses, your skin may become pale and then evolve to a gray or purplish-red colour. A bubbly appearance to your skin may become apparent, and the affected skin may make a crackling sound when you press on it because of the gas within the tissue. The bacterial infection produces toxins that release gas hence the name “gas” gangrene and can cause tissue death. Like wet gangrene, it can become life-threatening.
- Internal gangrene – Affects one or more of your organs, most commonly your intestines, gallbladder or appendix. This type of gangrene occurs when blood flow to an internal organ is blocked; for example, when your intestines bulge through a weakened area of muscle in your abdomen (hernia), and become twisted. Internal gangrene often causes a fever and severe pain. Left untreated, internal gangrene can be fatal.
- Fournier’s gangrene – It’s uncommon and involves the genital organs. Men are more often affected, but women can develop it as well. Usually arising from an infection in the genital area or urinary tract, it causes genital pain, tenderness, redness and swelling.
- Progressive bacterial synergistic gangrene (Meleney’s gangrene) – A rare type of gangrene which typically occurs after surgery, with painful skin lesions developing one to two weeks after.
When gangrene affects your skin, signs and symptoms may include:
- Discolouration — ranging from pale to blue, purple, black, bronze or red, depending on the type of gangrene
- Severe pain followed by a feeling of numbness
- A foul-smelling discharge leaking from a sore.
A condition called septic shock can occur if a bacterial infection that originated in the gangrenous tissue spreads throughout your body.
One or both of the following may be responsible:
- Lack of blood supply. Your blood provides oxygen, nutrients to feed your cells, and immune system components, such as antibodies, to ward off infections. Without a proper blood supply, cells can’t survive, and your tissue decays.
- Infection. If bacteria thrive unchecked for long, infection can take over and cause your tissue to die.
How is it diagnosed?
A person should suspect gangrene if any local body area changes colour (especially if it is red, blue, or black), and becomes numb or painful. If the symptoms include those stated above for either dry or wet gangrene, the individual should immediately seek medical help.
The diagnosis is usually based on the clinical symptoms of either wet or dry gangrene. Often other tests are done in cases of wet gangrene to further define the infecting agent(s), the type of gangrene, and the extent of the infection. For example, X-rays, CT, or MRI studies are done to see how far the infection has progressed from the local site. These studies are often done to help determine the extent of gangrene in both limb and internal types of gangrene.
Tissue that has been damaged by gangrene can’t be saved, but steps can be taken to prevent gangrene from spreading. These treatments include:
- Antibiotics – Given through a vein (intravenously), it may be used to treat gangrene that has become infected.
- Surgery – Your doctor removes the dead tissue, which helps stop it from spreading, and allows healthy tissue to heal. If possible, your doctor may repair damaged or diseased blood vessels in order to increase blood flow to the affected area.
A skin graft is a type of reconstructive surgery that may be used to repair damage to your skin caused by the gangrene. During a skin graft, your doctor removes healthy skin from another part of your body — usually a place hidden by clothing — and carefully spreads it over an affected area. The healthy skin may be held in place by a dressing or by a couple of small stitches. A skin graft can be done only if an adequate blood supply has been restored to the damaged skin.
In severe cases, an affected body part, such as a toe, finger or limb, may need to be surgically removed (amputated). In some cases, you may later be fitted with an artificial limb (prosthesis).
If tissue obtains good oxygenation by adequate arterial blood flow and does not become infected, then both dry and wet gangrene can be prevented. Consequently, avoiding tobacco use can prevent external trauma gangrene. Keeping patients with diabetes under good glucose control, and having them do daily home inspections of their feet for any signs of cuts, infection, or redness is also recommended. Patients with diabetic neuropathy (for example, numbness in extremities), should be extremely careful with the types of footwear they use and check at least morning and evening.
If any wound or burn occurs, it should be treated immediately to prevent infection. This is especially important in people with diabetes or a compromised immune system.
Some patients who notice coolness and redness of a local area (for example, toes, fingers), and get an angiogram that shows arterial blockage can have successful prevention of dry (and possibly the wet), if the vascular surgeon can remove the clot or obstruction in the artery before the local tissue dies.
Your feet mirror your general health . . . cherish them!