Gangrene, Fat necrosis, Gas gangrene

Question 1

Gangrenous types

Answer 1

1.dry gangrene
2.moist (wet) gangrene

Question 2

Dry gangrene

Answer 2

-ischemic coagulation necrosis (infarction) of extremities
>ergot (fungus causing constriction of vessels), frostbite, septicemia

Question 3

Gross appearance of dry gangrene

Answer 3

-shrunken, dry, brown to black

Question 4

Moist gangrene

Answer 4

-an area of coagulation necrosis which is further degraded by the liquefactive action of saprophytic bacteria
>aspiration pneumonia

Question 5

Gross appearance of moist gangrene

Answer 5

-soft
-moist
-red-brown to green-black with putrid odor

Question 6

Wet vs dry gangrene severity

Answer 6

-less severe in dry, more in wet

Question 7

Aspiration pneumonia

Answer 7

-wet gangrene
-aspirate vomit (bacteria, acid, nutrients) resulting in necrosis of the lung. Easy because gravity carries it there

Question 8

Gas gangrene

Answer 8

-penetrating wound infected with clostridia

Question 9

Gross examination of gas gangrene

Answer 9

-dark red to black with gas bubbles

Question 10

Blackleg

Answer 10

-caused by closteridium chauvoeli. Not introduced by penetrating wound therefore not genuine gangrene
-occurs when there is poor oxygen supply

Question 11

Gross appearance of blackleg

Answer 11

-dark red to black with gas bubbles
>hemorrage, dead tissue, gas bubbles

Question 12

Pancreatic fat necrosis

Answer 12

-areas of fat destruction by activated lipases within and around the pancreas
-lipases split the triglyceride esters contained within fat cells, then fatty acids combine with calcium resulting in fat saponification (chalky white)
**easier to see this than to see lesion within the pancreas

Question 13

Outcome of necrosis

Answer 13

-inflammatory reaction
>can be worse than initial cause
>will result in digestion and liquefying the necrotic tissue
-Regeneration
>if there are germinal cells, blood supply, tissue scaffold and removal of debris
-fibrosis
-sequestrum
-mineralization

Question 14

ID of necrosis

Answer 14

-swollen, pale, demarcated (short lived, tissue dependent)
-loss of strength, more friable
>reliable at early stages, but increase in firmness will occur resulting in fibrosis
>if calcified= white and gritty

Question 15

White muscle disease

Answer 15

-common in pigs
-Vitamin E and selenium deficiency (means inability to absorb free radicals)
-white muscle of the heart; calcification
>occurs in heart because it is a continuously working muscle and therefore lots of free radicals being produced

Question 16

Significance to animal

Answer 16

-depends on:
>location (brain and heart more fatal than elsewhere)
>size (functional reserve of affected organ)
>speed and progression
>sequels of necrosis (esophageal fibrosis, endothelial necrosis and thrombosis)

Question 17

Significance of necrosis to diagnostician

Answer 17

-character and location of necrosis may provide important clues about the cause and pathogenesis of the necrosis and death even though lesions themselves may not be of functional significance