Gas gangrene

1. Gas Gangrene

2. Learning Objectives
• What is GAS GANGRENE?
• Cause
– Organisms
– Risk factors
• Effect
• Clinical features
• Diagnosis
• treatment

3. What is gas gangrene?
• an infective gangrene
• caused by clostridial organisms
• involving mainly skeletal muscle as
oedematous myonecrosis.
• Earlier it was called as malignant oedema

4. Etiology
• Source:
– Contaminated, manured or cultivated soil
– Intestines
• Faecal flora
• Organism:
– Clostridium Welchii (perfringens): 60%
• Gram-positive, anaerobic central spore bearing,
nonmotile, capsulated
– Others-
• C. oedematiens; C. septicum; C. histolyticum

5. Clostridium Welchii
• Toxins produced:
– Alpha (most common); Beta; Epsilon; Iota
– Phi toxin-myocardial depressant
– Kappa toxin-destruction of connective tissue and
blood vessels
– Bursting factor and circulating factor
– Exotoxins:
• Lecithinase, Hemolysin, Hyaluronidase, Proteinase

6. Predisposing factors
• Crush wounds, following RTI
• Gunshot wounds- all war wounds
• After amputations
• Ischaemic limb
Injury or ischaemia or necrosis of the muscle due to
trauma predisposes infection.
Anaerobic environments in the wound- initial infection
with aerobic organism utilises existing oxygen in tissues

7. Effects of infection
• Extensive necrosis of muscle with production
of gas
– hydrogen sulphide; nitrogen; carbon dioxide
– muscle brown or black: anaerobic myositis/ myonecrosis
• Usually muscle is involved from origin to
insertion
• Often may extend into thoracic & abdominal
muscles
• When it affects the liver it causes necrosis
with frothy blood- foaming liver
• Rapidly spreading infection: often fatal

8. Effects of infection..
• Limbs are commonly involved;
– but organs like liver can also be affected
• Muscle glycogen is broken down into lactic
acid, CO2 and hydrogen.
• Proteinase released by organism forms amino
• acids which further releases ammonia and
hydrogen sulphide.
• Acid released earlier is neutralised by
ammonia and calcium to progress further
multiplication of organisms.

9. Clinical Features
• Site:
– limbs, abdominal wall, appendix, gallbladder, common bile
duct, intestine, uterus
• Features of toxaemia, fever, tachycardia (out of
proportion
to fever) pallor.
• Wound is under tension with foul smelling discharge
– Sickly sweety/decaying apple odour
• Khaki brown coloured skin due to haemolysis.
• Crepitus can be felt.
• Jaundice may be ominous sign
• Oliguria signifies renal failure.

10. Clinical subtypes
• Fulminant type
• Massive type
• Group type
• Single muscle type
• Subcutaneous type

11. Diagnosis
• Clinical diagnosis- characteristic
• Supporting investigations:
– X Ray part
– LFT, KFT, TLC, Blood gases
– CECT of part-??
– Gram stain
– RCM media- turns meat to pink, sour smell, acid
– 2% human serum culture media- Nagler reaction

12. Treatment
• Antibiotics:
– B. Penicillin + metronidazole + AMG/3rd gen.
Cephalosporins
• Blood transfusion
• Resuscitation: rehydration, u/o monitoring
• Polyvalent antiserum
• Hyperbaric oxygen
• Electrolyte management

13. Treatment..
• Surgery:
– Liberal incisions & adequate debridement
– Limb amputations- life saving
• Guillotine
– ** fumigation of ward/ O.R.
• Patients may require HDU/ICU care
*** early diagnosis & aggressive treatment

14. Gas gangrene is preventable
• Penicillin as prophylactic antibiotic
• Proper debridement of devitalised crushed
wounds
• Devitalized wounds should not be sutured
• Adequate cleaning of the wounds
• Frequent dressing and rechecking of wound

15. Thank you
Any questions?