Gangrene is the term used to describe the decay or death of an organ or tissue caused by a lack of blood supply. It is a complication resulting from infectious or inflammatory processes, injury, or degenerative changes associated with chronic diseases, such as diabetes mellitus
Gangrene may be caused by a variety of chronic diseases and post-traumatic, post-surgical, and spontaneous causes. There are three major types of gangrene: dry, moist, and gas (a type of moist gangrene).
Dry gangrene is a condition that results when one or more arteries become obstructed. In this type of gangrene, the tissue slowly dies, due to receiving little or no blood supply, but does not become infected. The affected area becomes cold and black, begins to dry out and wither, and eventually drops off over a period of weeks or months. Dry gangrene is most common in persons with advanced blockages of the arteries (arteriosclerosis) resulting from diabetes.
Moist gangrene may occur in the toes, feet, or legs after a crushing injury or as a result of some other factor that causes blood flow to the area to suddenly stop. When blood flow ceases, bacteria begin to invade the muscle and thrive, multiplying quickly without interference from the body's immune system.
Gas gangrene, also called myonecrosis, is a type of moist gangrene that is commonly caused by bacterial infection with Clostridium welchii, Cl. perfringes, Cl. septicum, Cl. novyi, Cl. histolyticum, Cl. sporogenes, or other species that are capable of thriving under conditions where there is little oxygen (anaerobic). Once present in tissue, these bacteria produce gasses and poisonous toxins as they grow. Normally inhabiting the gastrointestinal, respiratory, and female genital tract, they often infect thigh amputation wounds, especially in those individuals who have lost control of their bowel functions (incontinence). Gangrene, incontinence, and debility often are combined in patients with diabetes, and it is in the amputation stump of diabetic patients that gas gangrene is often found to occur.
Other causative organisms for moist gangrene include various bacterial strains, including Streptococcus and Staphylococcus. A serious, but rare form of infection with Group A Streptococcus can impede blood flow and, if untreated, can progress to synergistic gangrene, more commonly called necrotizing fasciitis, or infection of the skin and tissues directly beneath the skin.
Chronic diseases, such as diabetes mellitus, arteriosclerosis, or diseases affecting the blood vessels, such as Buerger's disease or Raynaud's disease, can cause gangrene. Post-traumatic causes of gangrene include compound fractures
, burns, and injections given under the skin or in a muscle. Gangrene may occur following surgery, particularly in individuals with diabetes mellitus or other long-term (chronic) disease. In addition, gas gangrene can be also be a complication of dry gangrene or occur spontaneously in association with an underlying cancer
In the United States, approximately 50% of moist gangrene cases are the result of a severe traumatic injury, and 40% occur following surgery. Car and industrial accidents, crush injuries, and gunshot wounds are the most common traumatic causes. Because of prompt surgical management of wounds with the removal of dead tissue, the incidence of gangrene from trauma has significantly diminished. Surgeries involving the bile ducts or intestine are the most frequent procedures causing gangrene. Approximately two-thirds of cases affect the extremities, and the remaining one-third involve the abdominal wall.
Areas of either dry or moist gangrene are initially characterized by a red line on the skin that marks the border of the affected tissues. As tissues begin to die, dry gangrene may cause some pain
in the early stages or may go unnoticed, especially in the elderly or in those individuals with diminished sensation to the affected area. Initially, the area becomes cold, numb, and pale before later changing in color to brown, then black. This dead tissue will gradually separate from the healthy tissue and fall off.
Moist gangrene and gas gangrene are distinctly different. Gas gangrene does not involve the skin as much, but usually only the muscle. In moist or gas gangrene, there is a sensation of heaviness in the affected region that is followed by severe pain. The pain is caused by swelling resulting from fluid or gas accumulation in the tissues. This pain peaks, on average, between one to four days following the injury, with a range of eight hours to several weeks. The swollen skin may initially be blistered, red, and warm to the touch before progressing to a bronze, brown, or black color. In approximately 80% of cases, the affected and surrounding tissues may produce crackling sounds (crepitus), as a result of gas bubbles accumulating under the skin. The gas may be felt beneath the skin (palpable). In wet gangrene, the pus is foul-smelling, while in gas gangrene, there is no true pus, just an almost "sweet" smelling watery discharge.
, rapid heart rate, rapid breathing, altered mental state, loss of appetite, diarrhea
, vomiting, and vascular collapse may also occur if the bacterial toxins are allowed to spread in the bloodstream. Gas gangrene can be a life-threatening condition and should receive prompt medical attention
A diagnosis of gangrene will be based on a combination of the patient history, a physical examination
, and the results of blood and other laboratory tests. A physician will look for a history of recent trauma, surgery, cancer, or chronic disease. Blood tests will be used to determine whether infection is present and determine the extent to which an infection has spread.
A sample of drainage from a wound, or obtained through surgical exploration, may be cultured with oxygen (aerobic) and without oxygen (anaerobic) to identify the microorganism causing the infection and to aid in determining which antibiotic will be most effective. The sample obtained from a person with gangrene will contain few, if any, white blood cells and, when stained (with Gram stain) and examined under the microscope, will show the presence of purple (Gram positive), rod-shaped bacteria.
X-ray studies and more sophisticated imaging techniques, such as computed tomography scans
(CT) or magnetic resonance imaging
(MRI), may be helpful in making a diagnosis since gas accumulation and muscle death (myonecrosis) may be visible. These techniques, however, are not sufficient alone to provide an accurate diagnosis of gangrene.
Precise diagnosis of gas gangrene often requires surgical exploration of the wound. During such a procedure, the exposed muscle may appear pale, beefy-red, or in the most advanced stages, black. If infected, the muscle will fail to contract with stimulation, and the cut surface will not bleed.
Gas gangrene is a medical emergency because of the threat of the infection rapidly spreading via the bloodstream and infecting vital organs. It requires immediate surgery and administration of antibiotics
Areas of dry gangrene that remain free from infection (aseptic) in the extremities are most often left to wither and fall off. Treatments applied to the wound externally (topically) are generally not effective without adequate blood supply to support wound healing. Assessment by a vascular surgeon, along with x rays to determine blood supply and circulation to the affected area, can help determine whether surgical intervention would be beneficial.
Once the causative organism has been identified, moist gangrene requires the prompt initiation of intravenous, intramuscular, and/or topical broad-spec-trum antibiotic therapy. In addition, the infected tissue must be removed surgically (debridement
), and amputation of the affected extremity may be necessary. Pain medications (analgesics
) are prescribed to control discomfort. Intravenous fluids and, occasionally, blood transfusions are indicated to counteract shock
and replenish red blood cells and electrolytes. Adequate hydration and nutrition
are vital to wound healing.
Although still controversial, some cases of gangrene are treated by administering oxygen under pressure greater than that of the atmosphere (hyperbaric) to the patient in a specially designed chamber. The theory behind using hyperbaric oxygen is that more oxygen will become dissolved in the patient's bloodstream, and therefore, more oxygen will be delivered to the gangrenous areas. By providing optimal oxygenation, the body's ability to fight off the bacterial infection are believed to be improved, and there is a direct toxic effect on the bacteria that thrive in an oxygen-free environment. Some studies have shown that the use of hyperbaric oxygen produces marked pain relief, reduces the number of amputations required, and reduces the extent of surgical debridement required. Patients receiving hyperbaric oxygen treatments must be monitored closely for evidence of oxygen toxicity. Symptoms of this toxicity include slow heart rate, profuse sweating, ringing in the ears, shortness of breath
, nausea and vomiting, twitching of the lips/cheeks/eyelids/nose, and convulsions.
The emotional needs of the patient must also be met. The individual with gangrene should be offered moral support, along with an opportunity to share questions and concerns about changes in body image. In addition, particularly in cases where amputation was required, physical, vocational, and rehabilitation
therapy will also be required.
Except in cases where the infection has been allowed to spread through the blood stream, prognosis is generally favorable. Anaerobic wound infection can progress quickly from initial injury to gas gangrene within one to two days, and the spread of the infection in the blood stream is associated with a 20-25% mortality rate. If recognized and treated early, however, approximately 80% of those with gas gangrene survive, and only 15-20% require any form of amputation. Unfortunately, the individual with dry gangrene most often has multiple other health problems that complicate recovery, and it is usually those other system failures that can prove fatal.
Patients with diabetes or severe arteriosclerosis should take particular care of their hands and feet because of the risk of infection associated with even a minor injury. Education about proper foot care
is vital. Diminished blood flow as a result of narrowed vessels will not lessen the body's defenses against invading bacteria. Measures taken towards the reestablishment of circulation are recommended whenever possible. Any abrasion, break in the skin, or infection tissue should be cared for immediately. Any dying or infected skin must be removed promptly to prevent the spread of bacteria.
— Organism that grows and thrives only in environments containing oxygen.
— Organism that grows and thrives in an oxygen-free environment.
— Build-up of fatty plaques within the arteries that can lead to the obstruction of blood flow.
— Without contamination with bacteria or other microorganisms.
— A staining procedure used to visualize and classify bacteria. The Gram stain procedure allows the identification of purple (Gram positive) organisms and red (Gram negative) organisms.
— Medical treatment in which oxygen is administered in specially designed chambers, under pressures greater than that of the atmosphere, in order to treat specific medical conditions.
— A condition characterized by the inability to control urination or bowel functions.
— The destruction or death of muscle tissue.
— The spreading of an infection in the bloodstream.
— The formation of a blood clot in a vein or artery that may obstruct local blood flow or may dislodge, travel downstream, and obstruct blood flow at a remote location.
Penetrating abdominal wounds should be surgically explored and drained, any tears in the intestinal walls closed, and antibiotic treatment begun early. Patients undergoing elective intestinal surgery should receive preventive antibiotic therapy. Use of antibiotics prior to and directly following surgery has been shown to significantly reduce the rate of infection from 20-30% to 4-8%.
Berktow, Robert, editor. The Merck Manual of Diagnosis and Therapy. 17th ed. Rahway, NJ: Merck Research Laboratories, 1997.
Basoglu, M., et al. "Fournier's Gangrene: Review of Fifteen Cases." American Surgeon November 1997: 1019-1021.
gangrene (gang'gren?, gan') [Gr. gangraina, an eating sore]
Necrosis or death of tissue, usually resulting from deficient or absent blood supply. See: illustration
Gangrene is usually caused by obstruction of the blood supply to an organ or tissue, e.g., from inflammation, injury, or degenerative changes such as arteriosclerosis. It is commonly a sequela of infections, frostbite, crushing injuries, or diseases such as diabetes mellitus and Raynaud disease. Emboli in large arteries in almost any part of the body can cause gangrene of the area distal to that point. The part that dies is known as a slough (for soft tissues) or a sequestrum (for bone). The dead matter must be removed before healing can take place.
The older or diabetic patient is assessed for arterial insufficiency related to decreases in the strength and elasticity of blood vessels. Capillary refill is also assessed. The presence and strength of distal pulses and the patient's normal sensation response to light and deep palpation are checked. Symmetry, color, temperature, and quantitative and qualitative changes in fingernails or toenails, skin texture, and hair patterns are assessed. Any unusual areas of pigmentation indicating new skin lesions or scarring from past injury or ulceration are observed and documented, with description given of the extent and nature of gangrene that is present.
If prescribed, vasodilating and thrombolytic agents are administered, and the patient's response is evaluated. If surgical intervention is required, the patient's understanding of the procedure, its desired effects, and possible complications are evaluated. Health care professionals collaborate with the surgeon to instruct and prepare the patient for surgery and the postoperative period. Care required will depend on the particular procedure. If amputation is required, the patient must understand that the level of amputation depends on determining the presence of viable tissues to ensure healing and the requirements for fitting a prosthesis. The entire health care team must understand the patient's perception of the amputation in order to assist with resolution of grief and adjustment to a permanent change in body image. Physical and occupational therapists help the patient deal with changes in mobility and ability to perform activities of daily living. The multidisciplinary rehabilitation team involves the patient, nurse, physician, social worker, psychologist, prosthetist, and physical and occupational therapists. The patient's age and presence of other body system dysfunctions affect immediate and long-term responses to treatment. The at-risk patient should be taught preventive measures such as avoiding exposure to cold; keeping the extremities covered with gloves, clean, dry socks, and well-insulated footwear; and promptly treating any breaks in skin integrity.
Gangrene, esp. of the lower extremities, occurring in some diabetics as a result of vascular insufficiency, neuropathy, and infection.
Gangrene that results when the necrotic part has a progressive reduction in its blood supply but does not typically become infected. This occurs when arterial blood flow to a tissue is obstructed. The tissue gradually dries, the process continuing for weeks or months.
Dry gangrene causes pain in the early stages. The affected part is cold and black and begins to atrophy. The most distal parts (the fingers or toes) are generally affected first. Dry gangrene is often seen in arteriosclerosis associated with diabetes mellitus.
Patient care concerns for dry gangrene are similar to those of moist gangrene. Necrotic matter must be removed and circulation to the remaining tissues ensured before healing can occur. The older diabetic patient with microvascular and macrovascular disease may experience very little pain because of a reduction in feeling produced by peripheral neuropathy. The condition may come to light only upon inspection. For this reason, all patients with diabetes mellitus or peripheral vascular disease should avoid cigarette smoking, be taught proper foot inspection and care, and show their feet to their caregivers at every office and/or home visit.
The recommended plan of care may include amputation of gangrenous tissue or observation while the tissue sloughs on its own. The gangrenous limb should be kept clean and dry and protected as much as possible from trauma or infection. Psychological needs resulting from the loss of a body part may require a psychiatric nurse practitioner, a psychologist, or a spiritual counselor of the patient's choice.
Gangrene arising after an embolic obstruction.
Fournier gangrene See: Fournier gangrene
Gangrene in a wound infected by a gas-forming microorganism, the most common causative agent being Clostridium perfringens
Gas gangrene is treated with débridement of the wound site, antibiotics, and clostridial antitoxin.
hospital gangreneNecrotizing fasciitis.
Gangrene of unknown cause.
Gangrene associated with acute infections and inflammation.
Synonym: wet gangrene
Gangrene that is wet as a result of tissue necrosis and bacterial infection. The condition is marked by serous exudation and rapid decomposition.
At first the affected part is hot and red; later it is cold and bluish, starting to slough. Moist gangrene spreads rapidly and carries a significant risk of local or systemic infection and occasionally death.
Gangrene developing in a part without previous inflammation.
Gangrene developing after local inflammation.
Gangrene on opposite sides of the body in corresponding parts, usually the result of vasomotor disturbances. It is characteristic of Raynaud disease and Buerger disease.
Tissue death caused by serious injuries, e.g., compartment syndrome or crush injury.
wet gangreneMoist gangrene.
Gangrene caused by local impairments of blood flow.