Gangrene is the medical term for the death of soft tissue as a result of the
loss of blood supply to the affected part of the body. The loss of blood
supply in turn can result from a disorder of the circulatory system, from
trauma, or from infection. Gangrene most commonly involves the fingers,
toes, hands, or feet, but can also develop within the internal organs.
There are two major types of gangrene, dry and wet. Dry gangrene is
caused by a gradual loss of blood flow through the arteries. It typically
develops slowly over a period of years as the person
impaired by atherosclerosis (hardening of the arteries), diabetes, or
long-term smoking.
Wet gangrene develops much more rapidly than dry gangrene. It is
caused by an untreated wound infection or by bacteria growing in tissue
that has broken down as a result of pressure. Bedsores are a type of wet
gangrene that may develop in patients who are bedridden for long periods
of time.
Gas gangrene is a deadly subtype of wet gangrene caused by bacteria
known as
in the absence of oxygen. It produces gas as well as toxins; these compounds
expand and spread rapidly through nearby tissues. Gas gangrene
is a medical emergency.Description
Dry gangrene typically begins in the parts of the hands and feet that are
furthest from the trunk of the body. These are the parts that are most likely
to lose their blood supply in patients with diseases that affect the circulatory
system. The affected area becomes cold and numb; it begins to turn red as
the blood cells inside the smaller vessels begin to break down. It then turns
a darker brown or blackish color. The dead tissue may eventually fall off if
it is not removed by surgery first.
Wet gangrene develops when the blood flow to the affected body part
is blocked
tissues supports the rapid growth of bacteria, which causes the tissues to
swell and produce a foul-smelling discharge. The affected area is usually
discolored and very painful, and the patient typically develops a fever. If
the gangrene is not treated, the bacterial infection can spread throughout
the body via the bloodstream and kill the patient. The possibility of death
from spreading infection is the reason why military surgeons from the time
of Augustus Caesar through the end of the nineteenth century routinely
amputated the limbs of wounded soldiers; the operations were necessary
to give the soldiers a chance to survive injuries to their arms or legs.
Gas gangrene is a type of wet gangrene caused by
a bacterium that grows in the absence of oxygen. In addition to
swelling and pain in the affected area, the tissue may also crackle or make
a popping sound if the doctor presses on the affected area. The patientwill become very sick very quickly with gas gangrene, often going into
shock, sweating heavily, and developing mental symptoms (confusion
and disorientation).
Demographics
The frequency of gangrene depends on the type. Gas gangrene is fortunately
rare in the United States, with an average of 900 to 1,000 cases
reported each year. According to the National Institute of Diabetes and
Digestive and Kidney Diseases (NIDDK), about 71,000 amputations
of the feet and lower legs are performed each year in the United States
on diabetics who have developed gangrene. More than 60 percent of allnontraumatic lower-limb amputations in the United States occur in
people with diabetes.
Both wet and dry gangrene affect both sexes and all races equally.
Risk factors for gangrene include:
•leading to gangrene or to be confined to bed and develop bedsores.
Old age. The elderly are more likely to develop circulatory disorders •
•
•
•
•
•blood vessels to narrow, reducing the supply of oxygen to body
tissues.
Diabetes. Diabetes tends to weaken the blood vessels over time.Diseases of the blood vessels.HIV infection.Radiation or chemotherapy for cancer.Severe injury, including frostbite.Long-term smoking. The chemicals in tobacco smoke cause the Causes and Symptoms
The basic cause of gangrene is the loss of blood supply to the soft tissues
in a part of the body. This loss may result from circulatory disorders,
from traumatic injury, or from infection.
The basic symptoms of wet and dry gangrene have already been
described. Gangrene is a serious condition, and anyone with any of the
following symptoms should see their doctor at once:
•appearance of the wound.
Pain in the affected area that is out of proportion to the outward •gas gangrene, the discharge has a mousy or slightly sweet odor.
A foul-smelling ooze or discharge leaking from a wound or sore. In •
•
Diagnosis
Skin that is colorless, pale, cold, and numb.Skin that is turning blue, brown, or black. The diagnosis of gangrene is based on a combination of the patient
a physical examination, a blood test, and imaging studies. The
doctor will ask the patient about any recent injuries, exposure to extreme
cold, recent surgery, chronic diseases (particularly diabetes), smoking
habits, and any disorders that affect the immune system. The physical
examination will include examination of the affected body part as well
as taking the patientTests and imaging studies that are usually done to evaluate gangrene
include.
•indicates an infection. A blood test may also be done to identify
the specific bacterium causing the infection (in wet gangrene).
Blood test. A higher than normal white blood cell count usually •soft tissue when gas gangrene is suspected.
X-ray study. This test may be performed to look for gas bubbles in •(MRI). These tests may be ordered to check for the spread
of gangrene.
Computed tomography (CT) scans and magnetic resonance imaging •on an x-ray is injected into the patient
help the doctor determine whether any of the patient
blocked. This type of test is usually done for patients with dry
gangrene.
Arteriogram. An arteriogram is a test in which a dye that shows up’s blood circulation. It can’s arteries are •examined under the microscope for signs of tissue death.
Removal of a sample of the affected tissue. The sample can be •be cultured in a laboratory to look for signs of
gas gangrene is suspected.
In some cases the patient may be taken directly into surgery to determine
how far the gangrene has spread inside the body.
Removal of a sample of fluid from the affected area. The fluid canC. perfringens when Treatment
Gangrene is a serious condition requiring treatment in a hospital.
A patient diagnosed with dry gangrene will be assessed by a surgeon who
specializes in vascular disorders to determine whether it is possible to
restore blood flow to the affected area. The tissue that has already died,
however, is usually removed surgically.
Wet gangrene requires immediate treatment with intravenous antibiotics
to stop the spread of infection and debridement (surgical removal
of the dead tissue). If the affected area is large, the patient may need a
skin graft to restore the appearance of the limb. In severe cases, the
patient
spread of infection to vital organs.
Gas gangrene is a medical emergency. The patient is given intravenous
antibiotics while the wound is debrided. Following surgery, thepatient may be placed in a hyperbaric oxygen chamber, a room in which
pure oxygen under pressure is delivered to the patient. Hyperbaric
oxygen raises the oxygen levels in the patient
help to fight the bacteria that cause gas gangrene.
’s blood, which in turn may Prognosis
The prognosis depends on the type of gangrene, the length of time before
the patient sought treatment, and the patient
conditions, and immune status. Dry gangrene usually has a better prognosis
than wet gangrene because it does not involve infection. Gas gangrene
has a mortality rate ranging from 25 percent in otherwise healthy
patients to 67 percent in patients being treated for cancer.
’s age, underlying medical Prevention
All people can prevent gangrene by cleansing wounds promptly with an
antiseptic; by watching for signs of infection in the wound (pus, redness,
swelling, and unusual pain); and by going to the doctor at once if a
wound looks infected.
People with diabetes need to take special care to prevent gangrene
in the feet, which is a potential complication of the disease. The reason
for this complication is that diabetes sometimes affects the nerves in the
feet, causing a loss of sensation. The diabetic person may not notice a
cut or other injury to the foot because they cannot feel it. An infection
can then develop and lead to gangrene. NIDDK recommends that
people with diabetes take the following precautions to prevent gangrene
in their feet:
•completely, particularly between the toes.
Wash the feet in warm (not hot) water every day and dry them •or toenail problems.
Check the feet every day for cuts, blisters, swelling, redness, calluses, •
•
•wearing sandals.
Cut the toenails once a week after washing the feet.Always wear shoes or slippers to protect the feet from injuries.Always wear socks or stockings to prevent blisters, even when •sure there are no rough edges that might injure the feet.
The Future
Gangrene will always be a potential complication of traumatic injuries as
well as such chronic diseases as diabetes and HIV infection. Recent
advances in wilderness and battlefield medicine have reduced the risk
of gangrene in injured hikers, explorers, and military personnel. Current
clinical trials are evaluating the effectiveness of new antibiotics in treating
diabetic foot gangrene and of hyperbaric oxygen therapy in treating gas
gangrene.
SEE ALSO
Diabetes; Frostbite; Necrotizing fasciitis For more information
BOOKS
Dvorchak, George.
of Outdoor Emergencies
Giesbrecht, Gordon G.
Survival, Rescue and Treatment
Books, 2006.
The Pocket First-Aid Field Guide: Treatment and Prevention. Accokeek, MD: Stoeger Publishing Company, 2007.Hypothermia, Frostbite, and Other Cold Injuries: Prevention,. 2nd ed. Seattle, WA: Mountaineers WEB SITES
eMedicine Health.
.com/gangrene/article_em.htm (accessed August 5, 2008).
Mayo Clinic.
gangrene/DS00993 (accessed August 5, 2008).
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK).
Gangrene. Available online at http://www.emedicinehealthGangrene. Available online at http://www.mayoclinic.com/health/ Prevent Diabetes Problems: Keep Your Feet and Skin Healthy
at http://diabetes.niddk.nih.gov/dm/pubs/complications_feet/ (accessed
August 6, 2008).. Available onlineWORDS TO KNOW
Amputation: Surgical removal of a limb.
Bedsore: A type of wet gangrene that develops
when a bedridden person cannot turn over to
relieve pressure on soft tissue caused by the
weight of the body. Bedsores are sometimes
called pressure ulcers.
Debridement: The medical term for the surgical
removal of dead or damaged soft tissue.Wear shoes that fit well, and check them before wearing to make’s toes, fingers, or limbs may have to be amputated to prevent the’s history,’s pulse, temperature, and blood pressure.—often by a traumatic injury—the blood that collects in the softClostridium perfringens,’s circulation isClostridium perfringens. C. perfringens is an organism that grows
Gangrene
Definition