54.13 Gas gangrene

This is an anaerobic infection of injured muscle caused by various species of clostridia. Suspect that it may occur if: (1) A patient has extensively lacerated muscles, or a missile wound, especially if this involves his buttocks, thighs, or axillae, or his retroperitoneal muscles following an injury to his colon. (2) The blood supply to these parts of his body has been interfered with. (3) His wound is grossly or deeply contaminated with soil.

Gas gangrene is probably developing f he has been progressing satisfactorily, and then suddenly deteriorates. Over a few hours he becomes anxious, frightened, or euphoric. His face (if he is Caucasian) becomes pale or livid, often with circumoral pallor. His injured limb feels uncomfortable and heavy. Although he has recovered from shock and is not bleeding, his pulse rises. It quickly becomes feeble as his blood pressure falls. He vomits.

Figure 54.13: MUSCLE CHANGES IN GAS GANGRENE. As the infection advances down a muscle, it changes from its normal purple, through brick red and olive green, to purplish black.

Don’t let these features mislead you: (1) He does not always smell of death, and even if he does, he may not have gas gangrene. (2) Gas in the tissues is a late sign, and even if it is present, it does not always mean gas gangrene.

One of the patient’s muscles may be involved, or more often a group of them, or a whole limb, or part of it. Infection spreads up and down a muscle, and has less tendency to spread from one muscle to another. As infection progresses along a muscle, it changes from brick red to purplish black, as shown in Fig. 54-13. At first the wound is relatively dry; later, you can express from its edges a thin exudate with droplets of fat and gas bubbles, which becomes increasingly offensive. Stain this by Gram’s method and look for Gram positive rods.

Prevent gas gangrene like this: (1) Do a thorough wound toilet, especially in all extensive muscle wounds of the buttock, thigh, calf, axilla or retroperitoneal tissues. (2) Give a patient with these wounds 1.5 megaunits of penicillin 4 hourly. If this is not possible, give him tetracycline. If you do a thorough wound toilet and give him penicillin, there is no need for prophylactic antiserum.

Once gas gangrene has developed, don’t delay exploring a patient’s wound because he is shocked. Radical excision and massive doses of penicillin are his only hope. You will be wise to excise too much muscle rather than too little.