Definition and Overview
In layman’s terms, gangrene means the death of body tissue. It commonly occurs when blood supply to a part of the body is cut off.
Every part of the body needs a regular supply of oxygen-rich blood. This is how they get the nutrients they need to survive. This is also how they get their supply of white blood cells (WBCs) that fight infections. If blood supply is cut off, the cells and tissues can die in a matter of hours.
There are many factors that can affect normal blood flow. The most common are the narrowing of blood vessels and formation of blood clots. Other possible causes are trauma and severe bacterial infection.
Gangrene can be either dry or wet. The dry form occurs when the tissue dries up because of lack of blood supply. The wet form, on the other hand, occurs due to an infection that causes pus to build up. The former can progress into the latter if the patient develops an infection. Between the two, the wet form is more serious because it can cause the infection to spread to other parts of the body. This form has four types, namely:
Internal gangrene - This damages the internal organs. It can affect the intestines as well as the appendix and gallbladder.
Gas gangrene - This occurs when bacteria releases deadly gases deep inside the body. This is a medical emergency. Unless treated promptly, the patient can die in a matter of days.
Fournier’s gangrene - This form affects the genitals. It can affect any person of any age, but it is more common in elderly men. Its risk factors are alcoholism and diabetes as well as having a weak immune system.
Meleney’s gangrene - This can occur after surgery. It is common in abdominal and thoracic procedures. It can develop days or weeks after surgery and is marked by extreme pain.
Causes of Condition
The main cause of gangrene is lack of blood supply. This can occur due to:
Blocked arteries. This can be due to plaque build-up or formation of blood clots.
Trauma - Traumatic injuries caused by stab or gunshot wounds can sever the arteries. Wounds can also allow pathogens to enter the body. This increases the risk of infection that can cause tissues and cells to die.
Frostbite - This can occur if a person is exposed to extreme cold. This can cause the blood vessels to narrow. When this happens, the flow of warm blood to the hands, feet, and face can be cut off.
People with conditions that can cause damage to the blood vessels have an increased risk for gangrene. These conditions include diabetes and blood vessel disease as well as obesity and smoking. Those with a suppressed immune system and taking illegal drugs also have an increased risk.
The first signs of gangrene are swelling and change in skin colour. The affected skin would often turn blue or black. The skin can also swell, and blisters filled with fluid can then develop. Unless treated at this point, more symptoms will appear. The skin can become cold to the touch. The sore can also leak a foul-smelling discharge. Other signs include severe pain followed by numbness.
If there is an infection, symptoms will also include a high fever, dizziness, and loss of appetite as well as shivering and a rapid heartbeat.
Who to See and Types of Treatments Available
The effects of gangrene cannot be reversed. Available treatments are used to:
Prevent the condition from progressing.
Treat existing complications and prevent new ones from occurring.
Remove dead tissue.
Treat or prevent infection.
Treat medical problems that caused the condition.
Dead tissue can be removed through debridement. It can also be done through conventional surgery. The dead tissue can be cut off using surgical tools or chemicals. The removal of dead tissue prevents the infection from spreading. In severe cases, the amputation of the affected body part (such as fingers, hands, toes, or feet) is necessary. Patients can be fitted with prostheses after surgery.
Antibiotics are also part of the treatment. These medications help the body fight infection. They also prevent new infections from developing. In some cases, hyperbaric oxygen therapy (HBOT) is also used to speed up the healing process. For this therapy, the patient goes into a special chamber where he or she inhales 100% oxygen. This therapy delivers an extra supply of oxygen to support the body’s own healing process. It is known to enhance the white blood cells’ ability to kill bacteria. It also promotes the growth of new blood vessels and reduces swelling.
Patients are also treated for their underlying medical conditions. Blood clots, for example, are treated with blood-thinning medications. They can also be treated with surgery. Surgery can remove blood clots and make the blood vessels wider. Diabetes and high blood pressure, on the other hand, are kept under control with medicines and lifestyle modifications.
When diagnosed and treated early, the prognosis is very good for patients with dry gangrene. However, the outlook is not as good for wet gangrene. This is especially true if the infection has already spread to the bloodstream. Unless treated promptly with antibiotic therapy and debridement, such cases can lead to death. Gas gangrene has the worst prognosis. It is associated with a high death rate because it causes the infection to quickly spread to the bloodstream.
Lipworth AD, et al., eds. Necrotizing soft tissue infections: Necrotizing fasciitis, gangrenous cellulitis, and myonecrosis. In: Fitzpatrick’s Dermatology in General Medicine. 8th ed. New York, N.Y.: McGraw-Hill; 2016. http://accessmedicine.mhmedical.com.
Yang, Z.; Hu, J.; Qu, Y.; Sun, F.; Leng, X.; Li, H.; Zhan, S. (2013). “Interventions for treating gas gangrene (Protocol)”. Cochrane Database of Systematic Reviews (6): Article number: CD010577.
Ziegler-Graham K, MacKenzie EJ, Ephraim PL, Travison TG, Brookmeyer R (March 2008). “Estimating the prevalence of limb loss in the United States: 2005 to 2050”. Arch Phys Med Rehabil. 89 (3): 422–9. PMID 18295618. doi:10.1016/j.apmr.2007.11.005.