Gangrene

Definition

Gangrene is the death of tissue caused by the lack of blood supply.

Description

The severity of gangrene is wide-ranging. It can affect a minuscule skin area or a finger or toe, or even an entire limb such as an arm, a foot, or a leg. Gangrene is usually classified into two categories, dry gangrene and wet gangrene.

Dry gangrene

Dry gangrene occurs when a portion of bodily tissue dies because its blood supply has been decreased or completely cut off. This type of gangrene will not spread to other healthy tissue, and infection is not present. It is usually a slow process, with the affected area gradually becoming cold, discolored, and eventually totally black. Shrinkage and withering away of the affected tissue occurs as the tissue dies.

Wet gangrene

Dry and wet gangrene are two terms often applied to different phases of the same death of tissue. Wet gangrene (also called moist gangrene) occurs when dry gangrene becomes infected, often due to injury, and the infection causes the tissue to die.

In the United States, approximately 50% of moist gangrene cases are the result of a severe traumatic injury; 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.

One particularly dangerous type of wet gangrene is termed gas gangrene, or myonecrosis. This particular type is caused by the infection of injured tissue or surgical wounds from the Clostridium species of bacteria , an especially virulent pathogen. In anaerobic conditions, that is, conditions in which oxygen levels are low, Clostridium can rapidly produce poisonous substances called toxins that cause tissue to die. Four of the Clostridium toxins, Alpha, Beta, Epsilon, and Iota, are capable of causing death.

Gas gangrene differs from other wet gangrenes because it is more involved with muscle than skin tissue. Not only do the toxins manufactured by Clostridium cause the death of tissue, but they also destroy blood cells, constrict blood vessels , thus decreasing circulation, and damage blood vessels so that they leak. Fortunately, in peacetime, and with improvements in medical care, gas gangrene is not a frequently occurring phenomenon. (It occurs in only between one and three thousand people in the United States each year.) However, in the past, in wartime, gas gangrene has killed literally millions.

Causes and symptoms

Dry gangrene

Some of the most common causes of dry gangrene include:

• arterial obstruction, or occlusion of an artery, caused by arteriosclerosis, diabetes mellitus , AIDS or blood clot
• severe blunt trauma to a part of the body causing damage and therefore obstruction of an artery

• frostbite, which occurs when tissue becomes so cold that it is literally deprived of blood and therefore oxygen, and dies
• diseases that affect the blood vessels, and especially the arteries, such as Buerger's disease or Raynaud's disease
• traumatic occurrences such as crushing injuries, fractures , burns , and even injections given into skin or muscle

Wet gangrene

Causative organisms for wet gangrene infection include:

• Streptococcus
• Staphylococcus

A serious but rare form of infection with Group A Streptococcus can impede blood flow and, if untreated, can progress to gangrene caused by chemical reaction. This type of gangrene is more commonly called necrotizing fasciitis, or infection of the skin and tissues directly beneath the skin.

Gas gangrene, the most serious form of wet gangrene, often is caused by Clostridium bacteria, which are normal inhabitants of the gastrointestinal, respiratory, and female genital tracts. They often infect thigh amputation wounds, especially in those individuals who have lost control of their bowel function (incontinence). Gangrene, incontinence, and debility are often combined in patients with diabetes, and it is in the amputation stumps of diabetic patients that gas gangrene often occurs.

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. The onset of dry gangrene is normally characterized by dull, aching pain at the site. The skin usually develops an abnormal, unhealthyappearing pallor and is cold to the touch. As tissues begin to die, dry gangrene may continue to cause some pain; but it may go unnoticed, especially in the elderly or in those individuals with diminished sensation to the affected area. As more tissue dies, its color changes to brown, and finally purplish-black. This dead tissue will gradually separate from the healthy tissue and fall off.

Gas gangrene has a dramatically sudden, rapid onset. It is frequently first noticed as a marked swelling and either a pallid or brownish-red colored area surrounding the wound site. The borders of the infected site can expand literally within minutes. Symptoms of gas gangrene include:

• edema, or swelling, at the injury site that expands quickly
• pain in the area surrounding the skin injury
• crepitus, a bubbly, crackling sound often heard upon palpation
• pallor at the injury site, then increasingly dusky discoloration
• low-grade to moderate temperature elevation
• tachycardia, or increased heart rate
• diaphoresis, or clammy, sweaty skin
• formation of blisters filled with rust-colored fluid
• wound drainage, foul-smelling and rusty or bloody in appearance
• in severe cases, shock (Symptoms of shock include generalized pallor, hypotension, rapid pulse, and cold hands and feet.)

Diagnosis

A diagnosis of gangrene is 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, possibly 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. A gangrenous sample 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.

Treatment

Gas gangrene is a potentially lethal condition requiring immediate action. It is recommended that anyone having any or all of the symptoms of gas gangrene contact a health provider immediately. Generally, once a diagnosis of gas gangrene is made, infected, gangrenous tissue must be removed surgically. To assure its complete removal, it is often necessary to remove all tissue surrounding the infection or even to amputate a portion of the body. Aggressive use of antibiotics , usually intravenously to start, is also begun as soon as possible. Pain medication will also usually be necessary.

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 effected 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-spectrum 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 dissolve 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 is 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 suffering from gangrene are also a large component of treatment. 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 is required, physical, vocational, and rehabilitation therapy will also be required.

Prognosis

Except in cases where the infection has been allowed to spread through the blood stream, as in the case of severe gas gangrene, prognosis for survival is generally favorable. Anaerobic wound infection can progress quickly from initial injury to gas gangrene and the spread of the infection to the blood stream within one to two days. Between 20 and 25% of gas gangrene victims do not survive. If recognized and treated early, however, approximately 80% of patients survive, and only 15 to 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 these health problems that can prove fatal.

Health care team roles

• In most cases, gangrene is discovered while the patient is still in a healthcare facility following trauma, surgery, or treatment of serious medical conditions. A diagnosis of gangrene is generally made by a primary care physician or surgeon.
• Both registered nurses (RNs) and licensed practical nurses (LPNs) must complete a prescribed course in nursing and pass a state examination. RNs typically have a degree in nursing. Both RNs and LPNs care for patients afflicted by gangrene both in general hospitals, homes, or other healthcare facilities. Good nursing care and observation are primary requirements. These will include taking vital signs , monitoring surgical wounds or injuries for signs and symptoms of infection, providing aseptic (germ-free) treatment to wounds and injuries, collecting specimens of wound drainage to be tested, and making all efforts necessary to keep the patient as comfortable as possible. Education about the underlying cause of the gangrene (diabetes, infection, etc.) is an important aspect of caring for these patients.

KEY TERMS

Aerobic —A type of organism that grows and thrives only in environments containing oxygen.

Anaerobic —A type of organism that grows and thrives in an oxygen-free environment.

Arteriosclerosis —Build-up of fatty plaques within the arteries that can lead to the obstruction of blood flow.

Aseptic —Without contamination with bacteria or other microorganisms.

Crepitus —A crackling sound.

Gram stain —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.

Hyperbaric oxygen —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.

Incontinence —A condition characterized by the inability to control urination or bowel functions.

Myonecrosis —The destruction or death of muscle tissue.

Sepsis —The spreading of an infection in the bloodstream.

Thrombosis —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.

• Clinical laboratory scientists have specialized training and must pass a state examination. They do the necessary tests on wound drainage specimens to determine the organism involved in the infection.
• Radiologic technologists have specialized training and must pass a state examination. They take X rays and other tests to visualize and monitor the course of the gangrene.
• Physical therapists must complete a prescribed course and pass a state examination in order to be licensed. Typically they have a degree. Physical therapists work with patients that have sustained an amputation because of gangrene to maintain and maximize mobility in walking, wheelchair use, and transferring (from wheelchair to toilet or from standing to sitting, for example). The physical therapist advises on such mobility aids as wheelchairs, braces, and canes.
• Social workers have a degree in social work. A social worker may help coordinate services and ease the transition out of the hospital back into the home or extended care facility, if necessary. Social workers may help counsel the patient and the family during the difficult rehabilitation period.
• Occupational therapists must complete a prescribed course and pass a state examination in order to be licensed. Typically they have a degree. They help people disabled after an amputation or loss of function caused by gangrene to relearn necessary functions needed to carry out normal activities of daily living such as bathing, dressing, and preparing meals.

All healthcare team members need to be aware that the person with gangrene, and possibly an amputation, and the family members who may care at home for the person will need to learn an entirely new set of skills and adaptations. Both the patient and family often experience stress , anxiety , and depression. Both may need teaching regarding both physical and mental symptoms that often follow gangrene or amputation, and the family may need to be taught how to deliver necessary care. For the patient with gangrene, finding other individuals or a support group composed of people that have had similar illness or injury can be one of the most important steps in the rehabilitation process.

Prevention

Patients with diabetes or severe arteriosclerosis need to 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 infected tissue should be cared for immediately. Any dying or infected skin must be removed promptly to prevent the spread of bacteria.

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 between 4 and 8%.

Resources

BOOKS

Berkow, Robert and Andrew Fletcher. The Merck Manual of Diagnosis and Therapy. Merck Research Laboratories, 1992.

Nettina, Sandra. The Lippincott Manual of Nursing Practice. Philadelphia: J.B. Lippincott Company, 2001.

Wyngaarden, James B., Lloyd H. Smith, and J. Claude Bennett. Cecil Textbook of Medicine. Philadelphia: W.B. Saunders Company, 1992.

OTHER

"Gas Gangrene." Medline, U.S. Department of Health and Human Services, National Institutes of Health. <http://www.nlm.nih.gov/medlingplus>. May 16, 2001.

Joan M. Schonbeck

Gangrene

Definition

Gangrene is the death of tissue caused by the lack of blood supply.

Description

The severity of gangrene is wide-ranging. It can affect a minuscule skin area or a finger or toe, or even an entire limb such as an arm, a foot, or a leg. Gangrene is usually classified into two categories, dry gangrene and wet gangrene.

Dry gangrene

Dry gangrene occurs when a portion of bodily tissue dies because its blood supply has been decreased or completely cut off. This type of gangrene will not spread to other healthy tissue, and infection is not present. It is usually a slow process, with the affected area gradually becoming cold, discolored, and eventually totally black. Shrinkage and withering away of the affected tissue occurs as the tissue dies.

Wet gangrene

Dry and wet gangrene are two terms often applied to different phases of the same death of tissue. Wet gangrene (also called moist gangrene) occurs when dry gangrene becomes infected, often due to injury, and the infection causes the tissue to die.

In the United States, approximately 50% of moist gangrene cases are the result of a severe traumatic injury; 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.

One particularly dangerous type of wet gangrene is termed gas gangrene, or myonecrosis. This particular type is caused by the infection of injured tissue or surgical wounds from the Clostridium species of bacteria, an especially virulent pathogen. In anaerobic conditions, that is, conditions in which oxygen levels are low, Clostridium can rapidly produce poisonous substances called toxins that cause tissue to die. Four of the Clostridium toxins, Alpha, Beta, Epsilon, and Iota, are capable of causing death.

Gas gangrene differs from other wet gangrenes because it is more involved with muscle than skin tissue. Not only do the toxins manufactured by Clostridium cause the death of tissue, but they also destroy blood cells, constrict blood vessels, thus decreasing circulation, and damage blood vessels so that they leak. Fortunately, in peacetime, and with improvements in medical care, gas gangrene is not a frequently occurring phenomenon. (It occurs in only between one and three thousand people in the United States each year.) However, in the past, in wartime, gas gangrene has killed literally millions.

Causes and symptoms

Dry gangrene

Some of the most common causes of dry gangrene include:

• arterial obstruction, or occlusion of an artery, caused by arteriosclerosis, diabetes mellitus, AIDS, or blood clot
• severe blunt trauma to a part of the body causing damage and therefore obstruction of an artery
• frostbite, which occurs when tissue becomes so cold that it is literally deprived of blood and therefore oxygen, and dies
• diseases that affect the blood vessels, and especially the arteries, such as Buerger's disease or Raynaud's disease
• traumatic occurrences such as crushing injuries, fractures, burns, and even injections given into skin or muscle

Wet gangrene

Causative organisms for wet gangrene infection include:

• Streptococcus
• Staphylococcus

A serious but rare form of infection with Group A Streptococcus can impede blood flow and, if untreated, can progress to gangrene caused by chemical reaction. This type of gangrene is more commonly called necrotizing fasciitis, or infection of the skin and tissues directly beneath the skin.

Gas gangrene, the most serious form of wet gangrene, often is caused by Clostridium bacteria, which are normal inhabitants of the gastrointestinal, respiratory, and female genital tracts. They often infect thigh amputation wounds, especially in those individuals who have lost control of their bowel function (incontinence). Gangrene, incontinence, and debility often are combined in patients with diabetes, and it is in the amputation stumps of diabetic patients that gas gangrene often occurs.

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. The onset of dry gangrene is normally characterized by dull, aching pain at the site. The skin usually develops an abnormal, unhealthy-appearing pallor and is cold to the touch. As tissues begin to die, dry gangrene may continue to cause some pain, but it may go unnoticed, especially in the elderly or in those individuals with diminished sensation to the affected area. As more tissue dies, its color changes to brown, and finally purplish-black. This dead tissue will gradually separate from the healthy tissue and fall off.

Gas gangrene has a dramatically sudden, rapid onset. It is frequently first noticed as a marked swelling and either a pallid or brownish-red colored area surrounding the wound site. The borders of the infected site can literally expand within minutes. Symptoms of gas gangrene include:

• edema, or swelling, at the injury site that expands quickly
• pain in the area surrounding the skin injury

• crepitus, a bubbly, crackling sound often heard upon palpation
• pallor at the injury site, then increasingly dusky discoloration
• low-grade to moderate temperature elevation
• tachycardia, or increased heart rate
• diaphoresis, or clammy, sweaty skin
• formation of blisters filled with rust-colored fluid
• wound drainage, foul-smelling and rusty or bloody in appearance
• in severe cases, shock (symptoms of shock include generalized pallor, hypotension, or low blood pressure, rapid pulse, and cold hands and feet)

Diagnosis

A diagnosis of gangrene is 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, possibly 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. A gangrenous sample 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), rodshaped 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.

Treatment

Gas gangrene is a potentially lethal condition requiring immediate action. It is recommended that anyone having any or all of the symptoms of gas gangrene contact a health provider immediately. Generally, once a diagnosis of gas gangrene is made, infected, gangrenous tissue must be removed surgically. To assure its complete removal, it is often necessary to remove all tissue surrounding the infection or even to amputate a portion of the body. Aggressive use of antibiotics, usually intravenously to start, is also begun as soon as possible. Pain medication will also usually be necessary.

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 broadspectrum 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 dissolve 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 is 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 suffering from gangrene are also a large component of treatment. 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 is required, physical, vocational, and rehabilitation therapy will also be required.

Prognosis

Except in cases where the infection has been allowed to spread through the blood stream, as in the case of severe gas gangrene, prognosis for survival is generally favorable. Anaerobic wound infection can progress quickly from initial injury to gas gangrene and spread the infection in the blood stream within one to two days. Between 20 and 25% of gas gangrene victims do not survive. If recognized and treated early, however, approximately 80% of patients 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 these health problems that can prove fatal.

Health care team roles

• In most cases, gangrene is discovered while the patient is still in a healthcare facility, following trauma, surgery, or treatment of serious medical conditions. A diagnosis of gangrene is generally made by a primary care physician or surgeon.
• Both registered nurses (RNs) and licensed practical nurses (LPNs) must complete a prescribed course in nursing and pass a state examination. RNs typically have a degree in nursing. Both RNs and LPNs care for patients afflicted by gangrene both in general hospitals, homes, or other healthcare facilities. Good nursing care and observation are primary requirements. These will include taking vital signs, monitoring surgical wounds or injuries for signs and symptoms of infection, providing aseptic (germfree) treatment to wounds and injuries, collecting specimens of wound drainage to be tested, and making all efforts necessary to keep the patient as comfortable as possible. Education about the underlying cause of the gangrene (diabetes, infection, etc.) is an important aspect of caring for these patients.
• Clinical laboratory scientists have specialized training and must pass a state examination. They do the necessary tests on wound drainage specimens to determine the organism involved in the infection.
• Radiologic technologists have specialized training and must pass a state examination. They take X rays and other tests to visualize and monitor the course of the gangrene.
• Physical therapists must complete a prescribed course and pass a state examination in order to be licensed. Typically they have a degree. Physical therapists work with patients that have sustained an amputation because of gangrene to maintain and maximize mobility in walking, wheelchair use, and transferring (from wheelchair to toilet or from standing to sitting, for example). The physical therapist advises on mobility aids such as wheelchairs, braces, and canes.
• Social workers have a degree in social work. A social worker may help coordinate services and ease the transition out of the hospital back into the home or extended care facility, if necessary. Social workers may help counsel the patient and the family during the difficult rehabilitation period.
• Occupational therapists must complete a prescribed course and pass a state examination in order to be licensed. Typically they have a degree. They help people disabled after an amputation or loss of function caused by gangrene to relearn necessary functions needed to carry out normal activities of daily living such as bathing, dressing, and preparing meals.

All healthcare team members need to be aware that the person with gangrene, and possibly an amputation, and the family members who may care at home for the person will need to learn an entirely new set of skills and adaptations. Both the patient and family often experience stress, anxiety, and depression. Both may need teaching regarding both physical and mental symptoms that often follow gangrene or amputation, and the family may need to be taught how to deliver necessary care. For the patient with gangrene, finding other individuals or a support group composed of people that have had similar illness or injury can be one of the most important steps in the rehabilitation process.

Prevention

Patients with diabetes or severe arteriosclerosis need to 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 infected tissue should be cared for immediately. Any dying or infected skin must be removed promptly to prevent the spread of bacteria.

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 between 4 and 8%.

KEY TERMS

Aerobic— A type of organism that grows and thrives only in environments containing oxygen.

Anaerobic— A type of organism that grows and thrives in an oxygen-free environment.

Arteriosclerosis— Build-up of fatty plaques within the arteries that can lead to the obstruction of blood flow.

Aseptic— Without contamination with bacteria or other microorganisms.

Crepitus— A crackling sound.

Gram stain— 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.

Hyperbaric oxygen— 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.

Incontinence— A condition characterized by the inability to control urination or bowel functions.

Myonecrosis— The destruction or death of muscle tissue.

Sepsis— The spreading of an infection in the bloodstream.

Thrombosis— 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.

Resources

BOOKS

Berkow, Robert and Andrew Fletcher. The Merck Manual of Diagnosis and Therapy. Merck Research Laboratories, 1992.

Nettina, Sandra. The Lippincott Manual of Nursing Practice. Philadelphia: J.B. Lippincott Company, 2001.

Wyngaarden, James B., Lloyd H. Smith, and J. Claude Bennett. Cecil Textbook of Medicine. Philadelphia: W.B. Saunders Company, 1992.

OTHER

"Gas Gangrene." Medline, U.S. Department of Health and Human Services, National Institutes of Health. 〈http://www.nlm.nih.gov/medlingplus〉. May 16, 2001.

Gangrene

Definition

Gangrene is the death of tissue caused by the lack of blood supply.

Description

The severity of gangrene is wide-ranging. It can affect a minuscule skin area or a finger or toe, or even an entire limb such as an arm, a foot, or a leg. Gangrene is usually classified into two categories, dry gangrene and wet gangrene.

Dry gangrene

Dry gangrene occurs when a portion of bodily tissue dies because its blood supply has been decreased or completely cut off. This type of gangrene will not spread to other healthy tissue, and infection is not present. It is usually a slow process, with the affected area gradually becoming cold, discolored, and eventually totally black. Shrinkage and withering away of the affected tissue occurs as the tissue dies.

Wet gangrene

Dry and wet gangrene are two terms often applied to different phases of the same death of tissue. Wet gangrene (also called moist gangrene) occurs when dry gangrene becomes infected, often due to injury, and the infection causes the tissue to die.

In the United States, approximately 50% of moist gangrene cases are the result of a severe traumatic injury; 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.

One particularly dangerous type of wet gangrene is termed gas gangrene, or myonecrosis. This particular type is caused by the infection of injured tissue or surgical wounds from the Clostridium species of bacteria, an especially virulent pathogen. In anaerobic conditions, that is, conditions in which oxygen levels are low, Clostridium can rapidly produce poisonous substances called toxins that cause tissue to die. Four

of the Clostridium toxins, Alpha, Beta, Epsilon, and Iota, are capable of causing death.

Gas gangrene differs from other wet gangrenes because it is more involved with muscle than skin tissue. Not only do the toxins manufactured by Clostridium cause the death of tissue, but they also destroy blood cells, constrict blood vessels, thus decreasing circulation, and damage blood vessels so that they leak. Fortunately, in peacetime, and with improvements in medical care, gas gangrene is not a frequently occurring phenomenon. (It occurs in only between one and three thousand people in the United States each year.) However, in the past, in wartime, gas gangrene has killed literally millions.

Causes and symptoms

Dry gangrene

Some of the most common causes of dry gangrene include:

• arterial obstruction, or occlusion of an artery, caused by arteriosclerosis, diabetes mellitus, AIDS, or blood clot
• severe blunt trauma to a part of the body causing damage and therefore obstruction of an artery
• frostbite, which occurs when tissue becomes so cold that it is literally deprived of blood and therefore oxygen, and dies
• diseases that affect the blood vessels, and especially the arteries, such as Buerger's disease or Raynaud's disease
• traumatic occurrences such as crushing injuries, fractures, burns, and even injections given into skin or muscle

Wet gangrene

Causative organisms for wet gangrene infection include:

• Streptococcus
• Staphylococcus

A serious but rare form of infection with Group A Streptococcus can impede blood flow and, if untreated, can progress to gangrene caused by chemical reaction. This type of gangrene is more commonly called necrotizing fasciitis, or infection of the skin and tissues directly beneath the skin.

Gas gangrene, the most serious form of wet gangrene, often is caused by Clostridium bacteria, which are normal inhabitants of the gastrointestinal, respiratory, and female genital tracts. They often infect thigh amputation wounds, especially in those individuals who have lost control of their bowel function (incontinence). Gangrene, incontinence, and debility often are combined in patients with diabetes, and it is in the amputation stumps of diabetic patients that gas gangrene often occurs.

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. The onset of dry gangrene is normally characterized by dull, aching pain at the site. The skin usually develops an abnormal, unhealthy-appearing pallor and is cold to the touch. As tissues begin to die, dry gangrene may continue to cause some pain, but it may go unnoticed, especially in the elderly or in those individuals with diminished sensation to the affected area. As more tissue dies, its color changes to brown, and finally purplish-black. This dead tissue will gradually separate from the healthy tissue and fall off.

Gas gangrene has a dramatically sudden, rapid onset. It is frequently first noticed as a marked swelling and either a pallid or brownish-red colored area surrounding the wound site. The borders of the infected site can literally expand within minutes. Symptoms of gas gangrene include:

• edema, or swelling, at the injury site that expands quickly
• pain in the area surrounding the skin injury
• crepitus, a bubbly, crackling sound often heard upon palpation
• pallor at the injury site, then increasingly dusky discoloration
• low-grade to moderate temperature elevation
• tachycardia, or increased heart rate
• diaphoresis, or clammy, sweaty skin
• formation of blisters filled with rust-colored fluid
• wound drainage, foul-smelling and rusty or bloody in appearance
• in severe cases, shock (symptoms of shock include generalized pallor, hypotension, or low blood pressure, rapid pulse, and cold hands and feet)

Diagnosis

A diagnosis of gangrene is based on a combination of the patient history, a physical examination, and the results of blood and other laboratory Gangrene 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, possibly 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. A gangrenous sample 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.

Treatment

Gas gangrene is a potentially lethal condition requiring immediate action. It is recommended that anyone having any or all of the symptoms of gas gangrene contact a health provider immediately. Generally, once a diagnosis of gas gangrene is made, infected, gangrenous tissue must be removed surgically. To assure its complete removal, it is often necessary to remove all tissue surrounding the infection or even to amputate a portion of the body. Aggressive use of antibiotics , usually intravenously to start, is also begun as soon as possible. Pain medication will also usually be necessary.

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 broadspectrum 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 dissolve 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 is 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 suffering from gangrene are also a large component of treatment. 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 is required, physical, vocational, and rehabilitation therapy will also be required.

Prognosis

Except in cases where the infection has been allowed to spread through the blood stream, as in the case of severe gas gangrene, prognosis for survival is generally favorable. Anaerobic wound infection can progress quickly from initial injury to gas gangrene and spread the infection in the blood stream within one to two days. Between 20 and 25% of gas gangrene victims do not survive. If recognized and treated early approximately 80% of patients 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 these health problems that can prove fatal.

Caregiver concerns

• In most cases, gangrene is discovered while the patient is still in a healthcare facility, following trauma, surgery, or treatment of serious medical conditions. A diagnosis of gangrene is generally made by a primary care physician or surgeon.
• Both registered nurses (RNs) and licensed practical nurses (LPNs) must complete a prescribed course in nursing and pass a state examination. RNs typically have a degree in nursing. Both RNs and LPNs care for patients afflicted by gangrene both in general hospitals, homes, or other healthcare facilities. Good nursing care and observation are primary requirements. These will include taking vital signs, monitoring surgical wounds or injuries for signs and symptoms of infection, providing aseptic (germ-free) treatment to wounds and injuries, collecting specimens of wound drainage to be tested, and making all efforts necessary to keep the patient as comfortable as possible. Education about the underlying cause of the gangrene (diabetes, infection, etc.) is an important aspect of caring for these patients.
• Clinical laboratory scientists have specialized training and must pass a state examination. They do the necessary tests on wound drainage specimens to determine the organism involved in the infection.
• Radiologic technologists have specialized training and must pass a state examination. They take x rays and other tests to visualize and monitor the course of the gangrene.
• Physical therapists must complete a prescribed course and pass a state examination in order to be licensed. Typically they have a degree. Physical therapists work with patients that have sustained an amputation because of gangrene to maintain and maximize mobility in walking, wheelchair use, and transferring (from wheelchair to toilet or from standing to sitting, for example). The physical therapist advises on mobility aids such as wheelchairs, braces, and canes.
• Social workers have a degree in social work. A social worker may help coordinate services and ease the transition out of the hospital back into the home or extended care facility, if necessary. Social workers may help counsel the patient and the family during the difficult rehabilitation period.
• Occupational therapists must complete a prescribed course and pass a state examination in order to be licensed. Typically they have a degree. They help people disabled after an amputation or loss of function caused by gangrene to relearn necessary functions needed to carry out normal activities of daily living such as bathing, dressing, and preparing meals.

KEY TERMS

Aerobic —A type of organism that grows and thrives only in environments containing oxygen.

Anaerobic —A type of organism that grows and thrives in an oxygen-free environment.

Aseptic —Without contamination with bacteria or other microorganisms.

Crepitus —A crackling sound.

Gram stain —A staining procedure used to visualize and classify bacteria. The Gram stain procedure allows the identification of purple (Grampositive) organisms and red (Gram-negative) organisms.

Hyperbaric oxygen —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.

Myonecrosis —The destruction or death of muscle tissue.

Sepsis —The spreading of an infection in the bloodstream.

All healthcare team members need to be aware that the person with gangrene, and possibly an amputation, and the family members who may care at home for the person will need to learn an entirely new set of skills and adaptations. Both the patient and family often experience stress, anxiety , and depression . Both may need teaching regarding both physical and mental symptoms that often follow gangrene or amputation, and the family may need to be taught how to deliver necessary care. For the patient with gangrene, finding other individuals or a support group composed of people that have had similar illness or injury can be one of the most important steps in the rehabilitation process.

Prevention

Patients with diabetes or severe arteriosclerosis need to 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 infected tissue should be cared for immediately. Any dying or infected skin must be removed promptly to prevent the spread of bacteria.

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 between 4 and 8%.

Resources

BOOKS

Berkow, Robert, and Andrew Fletcher. The Merck Manual of Diagnosis and Therapy. Merck Research Laboratories, 1992.

Nettina, Sandra. The Lippincott Manual of Nursing Practice. Philadelphia: J.B. Lippincott Company, 2001.

Wyngaarden, James B., Lloyd H. Smith, and J. Claude Bennett. Cecil Textbook of Medicine. Philadelphia:W.B. Saunders Company, 1992.

OTHER

“Gas Gangrene.” Medline, U.S. Department of Health and Human Services, National Institutes of Health. http://www.nlm.nih.gov/medlingplus. May 16, 2001.

Joan M. Schonbeck

Gangrene

Definition

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.

Description

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.

Symptoms

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.

Fever, 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

Diagnosis

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.

Treatment

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.

Prognosis

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.

Prevention

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.

KEY TERMS

Aerobic— Organism that grows and thrives only in environments containing oxygen.

Anaerobic— Organism that grows and thrives in an oxygen-free environment.

Arteriosclerosis— Build-up of fatty plaques within the arteries that can lead to the obstruction of blood flow.

Aseptic— Without contamination with bacteria or other microorganisms.

Crepitus— A crackling sound.

Gram stain— 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.

Hyperbaric oxygen— 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.

Incontinence— A condition characterized by the inability to control urination or bowel functions.

Myonecrosis— The destruction or death of muscle tissue.

Sepsis— The spreading of an infection in the bloodstream.

Thrombosis— 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%.

Resources

BOOKS

Berktow, Robert, editor. The Merck Manual of Diagnosis and Therapy. 17th ed. Rahway, NJ: Merck Research Laboratories, 1997.

PERIODICALS

Basoglu, M., et al. "Fournier's Gangrene: Review of Fifteen Cases." American Surgeon November 1997: 1019-1021.

Gangrene

Definition

Gangrene is a term used to describe the decay or death of an organ, tissue, or bone caused by a lack of oxygen and nutrients. It is a complication resulting from tissue injuries (such as frostbite), the obstruction of blood flow, or the processes of chronic diseases such as diabetes mellitus . Externally, the hands and feet are the areas most often affected by gangrene; internally, it is most likely to affect the gallbladder and the intestines. Gangrene is referred to as wet, or moist, if a bacterial infection is involved. In dry gangrene, there is no infection.

Description

Gangrene is often characterized by pain followed by numbness. The infection may first go unnoticed, especially in the elderly or those individuals with a loss of sensation. The area affected by gangrene may be cold and pale, especially early in the disease. Blisters may be apparent and the patient may experience an increased heart rate and profuse sweating. As the tissue dies, the skin begins to darken. The dead tissue gradually separates and falls away from the healthy tissue.

Dry gangrene is often seen in advanced cases of diabetes and arteriosclerosis. The tissue doesn't become infected, rather it dries out and shrivels over a period of weeks or months. Wet gangrene progresses much more rapidly. The affected area becomes swollen and gives off a foul smelling discharge. Death may occur within a matter of hours or days. Fever , rapid heart rate, rapid breathing, altered mental state, loss of appetite, diarrhea, vomiting , and vascular collapse may occur as the infection progresses.

Causes & symptoms

The primary cause of gangrene is often an injury to the blood vessels, causing either an interruption of blood flow, the introduction of a bacterial infection, or both. Such injuries may include burns , infected bedsores, boils , frostbite, compound fractures , deep cuts, or gunshot wounds . Gangrene can also develop due to the poor circulation and obstructions in the blood vessels associated with abnormal blood clots , torsion of organs, and diseases such as diabetes, heart disease , and Raynaud's disease. Gangrene of the internal organs may be attributed to a ruptured appendix, internal wounds, or the complications of surgery.

The bloodstream is the body's main transport system. When blood flow is diminished, the flow of the oxygen and nutrients needed to keep tissues healthy is greatly decreased. The white blood cells needed to fight infection are not readily available. In such an environment, invading bacteria thrive and multiply quickly. Streptococcus spp. and Staphylococcus spp. are the most common agents of external skin infection.

Gas gangrene, also called progressive or clostridial myonecrosis, is a type of moist gangrene most commonly caused by an infection of Clostridium perfringens, or other species that are capable of thriving under conditions where there is little oxygen. These bacteria produce gases and poisonous toxins as they grow in the tissues. Gas gangrene

causes the death of tissue, the destruction of red blood cells, and the damaging of the walls of the blood vessels and parts of the kidneys. Early symptoms include sweating, fear, and anxiety . Gas gangrene is a life-threatening condition and should receive prompt medical attention.

Diagnosis

A diagnosis of gangrene will be based on a combination of patient history, a physical examination, blood test results, and other laboratory findings. 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 to determine how much the infection has spread. A sample of drainage from a wound or obtained through surgery may be tested to identify the bacteria causing the infection and to aid in determining treatment. In the case of gas gangrene, the gas produced by the bacteria may be detected beneath the skin by pressing into the swollen areas. The crackling sounds of gas bubbles may also be heard in the affected area and the surrounding tissues.

X-ray studies and other imaging techniques, such as computed tomography (CT) scans or magnetic resonance imaging (MRI), may be helpful in making a diagnosis by showing evidence of gas accumulation or muscle tissue death. These techniques, however, are not sufficient alone to provide an accurate diagnosis of gangrene. Precise diagnosis often requires surgical exploration of the wound.

Treatment

Chelation therapy is a treatment that uses an intravenous solution containing the drug ethylenediamine tetra-acetic acid (EDTA), among other substances. In the bloodstream, EDTA binds and removes toxins and plaque formation on arterial walls. It promotes circulation throughout the body, and is reportedly, although not proven, able to reverse the processes leading to gangrene. Early intervention is necessary, however.

Other alternative and complementary treatments are used to treat gangrene. Herbal remedies such as goldenseal can be applied topically. Biofeedback and hypnosis can increase blood flow. Diabetics will receive herbal and traditional Chinese medicine remedies and nutritional supplements to help prevent gangrene.

Allopathic treatment

Pain medications and large amounts of intravenous antibiotics are given. Prompt surgical removal of infected and destroyed tissue is required for healing to take place. Gas gangrene is often treated with the antitoxin for clostridium as well. In a number of cases, amputation may have to be used to keep the infection under control.

In hyperbaric oxygen (HBO) therapy the patient is placed in a pressurized chamber and receives 100% pure oxygen to breathe. This has been shown useful in inhibiting the production of toxins in gas gangrene and for getting oxygen quickly to tissues, especially following a crushing injury that might lead to gangrene. HBO therapy must be carried out early in the process and used before any surgical removal. The therapy, though useful, does have adverse side effects. It requires skilled technicians and may not be widely available.

Expected results

The outcomes for gangrene are generally favorable if the infection is recognized and treated early in the progression of the disease. Left untreated, gas gangrene will result in a decrease in blood pressure, kidney failure, and coma. Overall, about 20% of those infected with gas gangrene die from the disease, and another 20% require an amputation. Gangrene is most dangerous to the elderly, those who are immuno-compromised, and those who have internal infections and chronic conditions such as diabetes. Individuals suffering from dry gangrene often have multiple health problems that complicate recovery and may prove fatal.

Prevention

Infections and injuries should be thoroughly cleaned and monitored; medical attention should be pursued if symptoms worsen or remain unresolved. Gastrointestinal wounds should be surgically explored, drained, and repaired. Use of antibiotic therapy prior to and directly following surgery has been shown to reduce the rates of infection.

Patients with diabetes or severe arteriosclerosis should take particular care of their hands and feet to avoid the decreased circulation and unchecked infection that may lead to gangrene. Any injury or infection, however slight, should be cared for promptly. There should be a focus on proper foot care, including keeping the feet clean, dry, and warm, wearing well-fitting shoes and not going barefoot. It is important to avoid smoking , since tobacco use constricts the blood vessels of the hands and feet, decreasing circulation.

Resources

BOOKS

Bunch, Bryan, ed. The Family Encyclopedia of Diseases: a Complete and Concise Guide to Illnesses and Symptoms. New York: Scientific Publishing, Inc., 1999.

The Burton Goldberg Group Alternative Medicine: The Definitive Guide. Tiburon, CA: Future Medicine Publishing, 1993.

OTHER

drkoop.com http://www.drkoop.com/conditions/foot_care/library/gangrene.asp.

drkoop.com http://www.drkoop.com/conditions/ency/article/000620.htm.

The Merck Manual http://www.merck.com/pubs/mmanual/section21/chapter292/292a.htm.

Patience Paradox