Gangrene is a condition where there is extensive damage to tissues or death of tissues. It may occur due to infection or an injury and a reduced supply of blood (and thereby oxygen) to the affected tissues.
Severe burns, extreme cold (frostbite), and untreated bed sores can also result in gangrene. The risk of acquiring gangrene is higher in individuals with severe medical conditions like diabetes, peripheral artery disease, or Raynaud’s syndrome.
In all cases, the primary reason for the death of cells (necrosis) and tissues is the disruption in blood supply.
Gangrene is not a very common condition, but it has high mortality rates.
Though it can occur in any part of the body, gangrene usually starts at the extremities, especially enveloping the toes, feet or the fingers.
There are three main types of gangrene:
- Dry / ischemic: This is due to poor blood supply from central blood vessels and causes ischemia (reduced blood supply and lack of adequate oxygen) in the lower extremities. When peripheral arteries are blocked, gangrene of the digits of the limbs sets in. It often starts at the toes, and usually affects elderly people.
Most individuals complain of pain in the affected limb. Initially there is pain only on exertion. However, it persists even when the person is in a rest position. It worsens when the leg is elevated. The affected part becomes grey or black with dead tissue. Also, hair loss and brittle nails are observed.
- Wet / moist: This is an acute condition affecting moist tissues of the bowel, lungs, and the cervix, and includes untreated infections arising from bed sores. It is a more serious condition than dry gangrene because of the bacterial infection.
People with an existing foot ulcer or complications due to diabetes suffer swelling, severe pain, loss of sensation and then paralysis of the affected limb.
- Gas gangrene: Gas gangrene typically has a history of trauma, like road accidents, crush injuries of limbs and gunshot wounds. When anaerobic bacteria infect the deep tissues, gas gangrene develops quickly
There is often pain, swelling and blisters filled with blood. Bacterial infection of the soft tissues causes changes in skin colour and shedding of tissues.
The bacteria produce toxins that destroy deep muscle tissues and release gas which spreads the infection quickly. It can also arise as a post-surgical complication with subsequent infection.
- When an internal organ like the gallbladder or the appendix is deprived of blood, it is called internal gangrene.
Who is vulnerable?
There is an increased risk of gangrene among people with certain pre-existing conditions or comorbidities. They include:
- People with diabetes or kidney failure
- Those with atherosclerosis and peripheral arterial disease – where fatty deposits result in narrowed down arteries and a reduction in blood supply to the limbs
- Those undergoing chemotherapy/radiotherapy
A physical examination of the region along with a detailed medical history is necessary for diagnosis. Your doctor might observe some obvious signs in the affected region such as foul odour and discoloured skin to start the treatment.
A few other tests can be carried out to confirm the diagnosis:
- Routine blood tests to check for infection
- Tissue culture and/or blood culture to determine the exact strain of the bacteria and the severity of the infection. Depending on their results, suitable antibiotics can be administered as directed by your doctor
- X-rays, CT scans and MRI help to gauge the spread of gangrene and locate the blockages
The cause of gangrene and its location determine the treatment.
- Surgery: It involves surgical cleaning of the wound, and debridement or removal of dead tissues. This may include amputation to prevent the gangrene from spreading to healthy tissue
- Bio surgery: New concepts of debridement involve using larvae that are cultured in labs and are free of microbes. The maggots are packed into the wound and a dressing is placed over them. They have proven to be useful as they feed only on dead tissue and help against infection
Other procedures may also be performed in cases of ischemic gangrene. They include the following procedures to repair the damaged blood vessels and improve blood circulation:
- Clot removal
- Balloon catheterisation or placement of stents to keep the affected artery open
- Bypass surgery to reconnect blood vessels
- Treatment with hyperbaric oxygen to speed up the healing process
Finally, the healed wound may be covered with a patch of healthy skin from another part of the body. The procedure is called skin grafting.
Medical treatment includes
- Injecting large doses of antibiotics, fluids and if necessary, blood transfusion as directed by your doctor
- Anti-clotting medicines prescribed by your doctor to prevent further blocks
- Statins to lower lipids in the blood and keep the arteries clean
- Managing comorbidities like diabetes which increase the risk of recurrence
- Protecting affected areas from cold temperatures
In individuals who survive gangrene, the loss of body parts impacts the quality of their life to a considerable extent. Even without amputation, there is usually significant pain and loss of function due to the deep cleaning and removal of dead tissue from the wound.
Gangrene can be prevented by following a healthy diet and lifestyle. Persons with diabetes should take good care of their feet and keep looking out for signs like numbness of the digits, ulcers, discolouration or swelling.