ENLmedical.com: Conditions And Concerns: Medical Encyclopedia: Gas gangrene

Gas gangrene

Causes and Risks:
Gas gangrene occurs as a result of infection by Clostridium species of bacteria that under anaerobic (low oxygen) conditions, produce toxins that cause the tissue death and associated symptoms.

Gas gangrene generally occurs at the site of trauma or a recent surgical wound . The onset of gas gangrene is sudden and dramatic. Inflammation begins at the site of infection as pale to brownish-red extremely painful tissue swelling . Gas may be felt in the tissue as a crackly sensation when the swollen area is pressed with the fingers. The margins of the infected area expand so rapidly that changes are visible over a few minutes of time. The involved tissue is completely destroyed.

Clostridia species of bacteria produce many different toxins, four of which (alpha, beta, epsilon, iota) are all fatal. In addition they cause tissue death ( necrosis ), destruction of blood ( hemolysis ), local decrease in circulation ( vasoconstriction ), and leaking on the blood vessels (increased vascular permeability). These toxins are responsible for both the local tissue destruction and the systemic symptoms (the other symptoms throughout the body).

Systemic symptoms develop early in the infection. These consist of sweating , fever , and anxiety . If untreated the individual develops a shock - like syndrome with decreased blood pressure ( hypotension ), renal failure , coma , and finally death.

Prevention:
Clean any skin injury thoroughly. Watch for signs of infection such as redness, pain, drainage, or swelling around the wound , and consult the health care provider promptly if these occur.

Symptoms:
initial symptoms:

moderate to severe pain around a skin injury
progressive swelling around a skin injury
moderate to low fever
skin color initially pale , later dusky to highly discolored
skin color progressing to dark red or purple
vesicle ( blister ) formation, coalescent (combine into large blisters )
blisters filled with brown-red fluid
drainage from the tissues, foul-smelling brown-red or bloody fluid ( serosanguineous discharge)
increased heart rate ( tachycardia )
sweating
subcutaneous emphysema

Note: Symptoms usually begin suddenly and rapidly and progressively worsen.

Signs and Tests:
Shock may be present, as evidenced by general pallor , cold extremities, low blood pressure , and rapid heart rate . Air in the tissues ( crepitus ) may be felt. Infection involving the entire body ( systemic toxicity or sepsis ) may develop. Yellow skin color associated with the excessive breakdown of blood cells ( jaundice ) is possible.

A gram stain of fluid from the infected area shows gram positive rods and spoke formation.
An anaerobic tissue and/or fluid culture reveals Clostridium species.
An X-ray , CT scan, or MRI of the area shows gas in the tissues.

Treatment:
Prompt surgical removal of dead, damaged and infected tissue (debridement) is necessary. Amputation may be indicated to control the spread of infection.

Antibiotics, preferably penicillin-type, should be given. Initially, this is given intravenously (through a vein). Analgesics may be required to control pain.

Hyperbaric oxygen has been tried with varying degrees of success.

Prognosis:
Gas gangrene is progressive and often lethal. Immediate medical attention is required.

Complications:

disfiguring or disabling permanent tissue damage
jaundice with liver damage
kidney failure
spread of infection systemically through the body ( sepsis )
shock
stupor
delirium
coma

Call Your Healthcare Provider:
Call your heath care provider if signs of infection occur at any time around a skin wound ; including pain, swelling , redness, drainage of pus or blood, fever , or similar symptoms.

Go to the emergency room or call the local emergency number (such as 911) if symptoms indicate gas gangrene. This is an emergency condition requiring immediate medical attention!