Gangrene

Question 1

2 Main types of gangrene

Answer 1

• Dry gangrene
• Moist gangrene

Question 2

Causes of gangrene

Answer 2

1. Necrosis: sudden ischemia or bacterial toxins
2. Putrefaction: saprophytic bacteria break down ptn into hydrogen sulfide (bad odor) , hydrogen sulfide binds to iron of hemoglobin to form iron sulfide (black color)

Question 3

Dry gangrene is caused by:

Answer 3

gradual occlusion of an Artery ( ex: atherosclerosis)

Question 4

moist gangrene is Caused by:

Answer 4

sudden Arterial or Venous occlusion

Question 5

Compare between Dry gangrene & moist gangrene

Answer 5

• Dry gangrene occurs mainly in limbs and in old age (senile) #️⃣ Moist gangrene occurs mainly in internal organs (preferably intestines)
• Dry gangrene has slow spread & slow putrefaction, so it’s dry #️⃣ Moist gangrene has rapid spread & rapid putrefaction
• Dry gangrene shows mild toxemia #️⃣ Moist gangrene shows Severe toxemia (fatal)
• Dry gangrene is Dry, Shrunken, Black, mummified #️⃣ Moist gangrene is edematous & swollen
• Dry gangrene has prominent lines of Demarcation & seperation –> self Amputation #️⃣ Moist gangrene has NO lines of demarcation & seperation

Question 6

explain why intestines are more common site of moist gangrene

Answer 6

• No surface for evapouration (internal)
• Saprophytic bacteria is more prominent in intestines

Question 7

Define line of demarcation

Answer 7

red zone of Acute inflammation between healthy & necrotic tissue, caused by irritation of Healthy tissue by the necrotic tissue

Question 8

Define line of Seperation

Answer 8

• groove near line of demarcation formed by healing by granulation & fibrosis
• It deepens gradually until the dead gangrenous part seperate from living tissue leaving conical stump

Question 9

Diabetic gangrene is more common in ___

Answer 9

females age 45

Question 10

explain why Diabetic gangrene occurs

Answer 10

due to Hyperlipidemia & hyperglycemia
* + sensory loss & low immunity

Question 11

explain why Diabetic gangrene starts off Dry then becomes moist

Answer 11

• there is low immunity
• excessive blood sugar

this causes Rapid spread in bacteria, memicing moist gangrene

Question 12

clinical procedure after diagnosis of Diabetic gangrene

Answer 12

surgical amputation

Question 13

Explain how bed sores occur

Answer 13

1. Skin ulcers over bony prominence due to prolonged recumbenence
2. blood strangulation
3. thrombosis
4. bacterial infection

Question 14

explain how Infective gangrene occurs

Answer 14

pathogenic bacteria causes necrosis –> saprophytic bacteria acts on the necrotic tissue

Question 15

Examples of Infective gangrene

Answer 15

• Lung gangrene (due to lung abscess)
• Cancrum oris/ Gangrenous stomatitis

Question 16

Bacteria of Cancrum oris

Answer 16

• Treponema vincenti
• bacillus fusiform

Question 17

Bacteria of gas gangrene

Answer 17

gm +ve bacteria:
* Clostridium perfringes
* Clostridium Welchii