Gas gangrene

Question 1

What is the other name for gas gangrene?

Answer 1

CLOSTRIDIAL MYONECROSIS

Question 2

Who does gas gangrene effect?

Answer 2

Equal M=F

Question 3

Where is the normal location for gas gangrene?

Answer 3

BUTTOCKS
THIGH
PERINEUM

Question 4

what are the risk factors for gas gangrene?

Answer 4

Post traumatic- assoc with Clostridium perfringens
   RTA- most common
    crush injuries
     gunshot wounds with foreign bodies
     Burns and frostbite
     Iv drug abuser
Post-operative
         bowel resection for peroration
          biliary surgery
Premature wound closure
Sponatenous- colon cancer
                       neutropenia

Question 5

Name the pathogens of gas gangrene?

Answer 5

CLOSTRIDIUM SPECIES
C. PERFINGES -most common
C novyi
C. septicum

Question 6

Where are these organisms found?

Answer 6

In the soil and gut flora

Question 7

What are these bacteria?

Answer 7

Gram positive obligate ANAEROBIC SPORE FORMING RODS that PRODUCE EXOTOXINS- e.e C perfringes = alpha toxin
-> muscle necrosis and vessel thrombosis
can cause haemolysis and shock

Question 8

What is the incubate period?

Answer 8

<24hrs

Question 9

Where is the gas produced from?

Answer 9

By fermentation of glucose

the main component is NITROGEN

Question 10

What other bacteria cause gas gangrene ?

Answer 10

E coli, Pseudomonas aeruginosa, proteus species, klebisella pneumoniae

Question 11

What is the prognosis?

Answer 11

25% mortality
50% morbidity if bacteremic
100% mortality if tx delayed
poorer prognosis for older pts with comorbidies

Question 12

What is there PC?

Answer 12

Triad- Progressive PAIN out of PORTION CF injury ( from thrombosis occlusion of large vessels)
TACHYCARDIA not explained by fever
FEELING OF IMPENDING DOOM

Question 13

What is there to find on examination?

Answer 13

Sweet smelling door
swelling, discolouration and ecchymosis
blebs and haemorrhagic BULLAE
DISHWATER PUS
CREPITUS
altered MENTAL STATE

Question 14

What is shown on radiographs ?

Answer 14

LINEAR STREAKS of gas in SOFT TISSUES

Question 15

What is found on lab studies?

Answer 15

ELEVATED LDH
ELEVATED WBC
METABOLIC ACIDOSIS and RENAL FAILURE

Question 16

What is found on Histology studies?

Answer 16

Gram satin = GRAM POSITIVE BACILLI
ABSENCE OF NEUTROPHILS
LACK OF ACUTE INFLAMMATORY RESPONSE- hallmark of gas gangrene

Question 17

What is the differential dx?

Answer 17

Necrotising fasciitis

Question 18

How is gas gangrene treated?

Answer 18

1)HIGH DOSE IV ANTIBIOTICS
1st line- PENCILLIN G and CLARITHROMYCIN
OR ERYTHROMYCIN, TETRACYCLINE OR CEFRIAXONE
( clindamycin and tetracycline inhibit toxin synthesis)

2) HYPERBARIC 02- useful adjust- effectiveness is inconclusive
3) Operative- RADIAL SURGICAL DEBRIDEMENT WITH FASCIOTOMIES*** 1ST LINE IS SURGERY

Question 19

What are the complications of gas gangrene? what are they mediated by?

Answer 19

SHOCK
RENAL FAILURE

BY TNF alpha, IL-1, IL-6