MYONECROSIS

OR GAS GANGRENE

Dr. Mansoor KhanResident Surgery, MBBS, FCPS-I

Khyber Teaching Hospital, Peshawar

BACTERIA

GRAM (+) GRAM (-)

AEROBIC ANAEROBIC AEROBIC ANAEROBIC

CLOSTRIDIUM

CLOSTRIDIUM PERFRINGENS

Clostridium perfringens A is important in human

Cellulitis: Infection with gas formationin the soft tissue.

Fasciitis or suppurative myositis:Infection and gas in the muscle planes.

Myonecrosis:or gas gangrene:a life-threatening disease.

Range of infections

Spores germinate

Distension oftissues

InterferingBlood supply

Ischemia/gangrene

Toxemia anddeath

vegetative cells multiply

Spores germinate

CarbohydratesFermentation

Gas productionIn tissues

PATHOGENESISIncubation period is

1-7 days

Crepitation in tissues,foul smelling discharge,

rapidly progressing necrosis,fever, hemolysis, toxemia, shock,

renal failure, and death

Presentation

Culture and sensitivity

Storming fermentation

Lecithinase test

Lab. Investigations

G

A

S

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F

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U

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G

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R

U

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G

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I

N

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G

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(1) Do a thorough wound toilet.(2) In high risk wounds give the patient penicillin 1.5 megaunits 4 hourly, or tetracycline

Prevention

Isolate the patient from other surgical patients

10 megaunits of benzyl penicillin daily for 5 days as

four 6 hourly doses.

OrTetracycline 0.5 g

intravenously or 1 g orally every 6 hours.

Clostridia not sensitive to metronidazole, some other anaerobic bacteria are, so give it.

Do this in a septic theatre, or even in the out-patient department,

and not where clean cases go for operation.

EXPLORATION

AMPUTATION

Amputate under a tourniquet Close the stump by delayedprimary suture

Fournier,s gangrene

Myonecrosis of right leg

Myonecrosis of left foot

Stump of above knee amputation

Dr. Mohammad ZarinFCPS, MRCS (Eng), FMASAssistant Prof. SCW

A disease caused by Clostridium tetani characterized by local or generalized spasmodic contraction of muscles

Gram positive, anaerobic, spore forming rods

Clostridium tetani

Contamination of devitalized tissue with the spores, germination of the spores,

release of tetanospasmin, the toxin reaches CNS by retrograde axonal transport or via the bloodstream

the toxin is fixed to gangliosides in spinal cord or brainstem and exerts its actions

TETANOSPASMIN

Inhibits release of an inhibitory mediator

(e.g., GABA or glycine) which acts on

postsynaptic spinal neurons

(causing spastic paralysis).

Localized tetanus

Confined to the musculature of

primary site of infection

Neonatal tetanus

(infection of the umbilical wound):

mortality > 90%, and developmental defects are present in survivors.

Generalized tetanus first the area of injury, then the muscles of the jaw (trismus or lockjaw risus sardonicus.

Other voluntary muscles become involved gradually, resulting in generalized tonic spasms (opistotonus).

Death usually results from interference with respiration. The mortality rate of generalized tetanus: ~50%.

Prevention is much more important than treatment:

1. Active immunization with toxoid.

‘Booster shot’ for previously immunized individuals. This may be accompanied by antitoxin injected into a different area of the body.

2. Proper care of wounds. Surgical débridement to remove

the necrotic tissue.

3. Prophylactic use of antitoxin.

4. Antibiotic treatment. Metronidazole

*Patients with symptoms of tetanus should receive muscle relaxants, sedation and assisted ventilation.

Prevention and treatment

Prophylaxis

THANKS