Gangrene refers to the death of tissues of your body due to a lack of adequate blood supply or a serious bacterial infection. In majority of the cases, gangrene occurs in regions farthest from your heart, such as toes and fingers. However, it can also affect other body parts, including internal organs such as the gall bladder. Gangrene is considered a medical emergency and should be treated as soon as possible. Lack of treatment or delay can spread gangrene to the entire limb, in which the affected limb will have to be amputated. In severe cases, it can progress to a septic shock, leading to death.
Lack of sufficient blood supply and bacterial infections are the most common causes of gangrene. Your blood carries oxygen and nutrients necessary for the proper functioning and growth of body tissues. If blood supply is constricted or cut off due to some reason, the affected tissue regions will begin to die. This results in gangrene. Blood supply can be compromised due to cardiovascular diseases, thromboembolic diseases, and the buildup of cholesterol in arteries (atherosclerosis). Diseases such as diabetes and hypertension can increase the risk of gangrene.
Gangrene can also result as a consequence of a severe bacterial infection. A gunshot wound or injury from a car accident results in open wounds that are exposed to several bacteria. These bacteria can penetrate deep into your skin and cause the death of tissues. Gangrene can also occur as a result of severe temperatures such as frostbite or sunburn. Poor blood circulation can further accelerate the spread of gangrene.
Gangrene is generally divided into three types on the basis of its clinical presentation: dry, wet, and gas gangrene.
Dry gangrene occurs due to a lack of adequate blood supply. People with diabetes or cardiovascular diseases are more prone to develop dry gangrene. The most common cause of dry gangrene is atherosclerosis. The affected regions appear dry and dark in color.
Wet gangrene occurs in the case of a bacterial infection. The causative bacteria cause swelling, inflammation, and pus discharge, resulting in a wet appearance. The affected tissues appear darker in color, with blisters or swelling present. It can also occur due to sunburn or frostbite.
Gas gangrene affects the deeper layers of your muscles. The superficial skin may look normal at first, but it begins to change color as the condition worsens. Bubbles appear on the skin because of gas accumulation in the tissues. Many bacteria can cause gas gangrene, but the most common pathogen is Clostridium perfringens.
Several risk factors can increase the chance of developing gangrene. Among these, diabetes is the most common factor. High blood sugar levels can damage your blood vessels. You may begin losing sensation in your foot region at first which may increase in severity. Blood vessel diseases such as atherosclerosis can also put you at risk of dry gangrene. Other possible risk factors include traumatic injury, surgery, smoking, obesity, immunosuppression, drug abuse, and injection of certain medications.
Around 1% of people in the United States develop dry gangrene in their toes or fingers due to constriction or lack of blood supply. Cases of wet gangrene occur more often than gas gangrene. All types of gangrene can affect people at any age, although they are seen frequently among the older population.
The signs and symptoms of gangrene may vary slightly depending on its type. In many cases, gangrene begins with skin discoloration. Depending on the type, the affected region of your skin may turn brown, black, red, purple, or blue. People with dry gangrene will have blackish or brown-colored skin, which will have a dry and shriveled appearance. Wet gangrene is accompanied by blistering or swelling in the affected site. In gas gangrene, there may be an appearance of bubbles that crack when pressed. You will experience severe pain in the initial stages, followed by numbness. Gangrenous tissues have a foul smell and feel cold to touch, unlike normal body tissues. You may also develop other symptoms such as fever, low blood pressure, rapid heartbeat, fatigue, and shortness of breath.
Your doctor will require a detailed medical history to suspect the possible causes of gangrene. This is followed by a clinical examination of the wound. The type of gangrene is decided based on its clinical appearance. Further tests are required to diagnose the cause. A complete blood count is ordered to check the amount of white blood cells. An abnormally high amount of WBCs can be a sign of infectious gangrene. Samples of the affected tissues or fluid discharge are also taken and tested for causative bacteria. Imaging tests such as X-rays, CT scans, and MRI can be used to determine the spread of gangrene.
Gangrene should be differentiated from other conditions that may present with a similar appearance. These include compartment syndrome, toxic shock syndrome, group A streptococcus infections, ergotism, calciphylaxis, and septic shock.
Gangrene is treated as a medical emergency. The tissues that have already necrosed due to gangrene cannot be saved, but it is important to limit the spread of this disease. The initial process begins with tissue debridement in which the dead tissues are removed. If a whole body part has been affected, such as a toe or finger, it will need to be amputated. This is done to control spread and reduce the risk of severe infection. Skin grafting surgery can be done to replace the damaged tissues with healthy skin tissues. Hyperbaric oxygen therapy can also be used to improve the oxygen supply to tissues. This can limit the growth of bacteria and accelerate wound healing.
Antibiotics are given orally or intravenously to kill bacteria or reduce the risk of further infection. Pain killers such as narcotics or opioids may be provided to reduce initial pain.
Prognosis of gangrene depends on its type, severity, the extent of spread, and presence or comorbidities. Among all types, gas gangrene has the highest fatality rate. Other types can be treated by tissue debridement and necessary surgical procedures.
Gangrene can be prevented in some cases by maintaining your health. If you have diabetes or any cardiovascular disease, consult a specialist for proper guidance and medications to manage these conditions. Maintain a healthy diet and exercise regularly to improve blood circulation. Avoid smoking and the use of illegal drugs. If you get any open wound, get it checked by a physician and take proper care of it, keeping it clean and dry until it heals.
Our clinical experts continually monitor the health and medical content posted on CURA4U, and we update our blogs and articles when new information becomes available. Last reviewed by Dr.Saad Zia on May 19, 2023.
Gangrene - StatPearls - NCBI Bookshelf (nih.gov)
Gangrene - NHS (www.nhs.uk)