This document discusses gangrene, which is defined as the invasion and petrification of necrotic tissue by saprophytic bacteria. It commonly occurs in the lungs, intestines, and extremities. There are two main types of gangrene - dry gangrene and moist gangrene. Dry gangrene occurs where moisture and temperature limit bacterial growth, resulting in a dry, shriveled appearance. Moist gangrene occurs where moisture and heat allow rapid bacterial growth in tissues like the lungs and intestines, often resulting in death from sepsis, toxemia and shock. The document describes the gross and microscopic appearances of both dry and moist gangrene.

1. GANGRENE
UNIT-I
VETERINARY PATHOLOGY (PAPER-I)
DR. KAUSHAL KUMAR
Assistant Professor & Head
Department ofVeterinary Pathology
BiharVeterinary College, BASU, Patna, Bihar

2. INTRODUCTION
• It is defined as Invasion and petrification of necrotic tissue by saprophytic bacteria.
• Most Commonly seen in:
• LUNG (due to faulty drenching/infected stomach tube)
• INTESTINE (due to torsion)
• EXTREMETIES(due to freezing/ergot poisoning/Se Toxicity/Fusarium toxicity)

3. Classification of GANGRENE
• Depending on:
 Temperature of tissue
 Moisture content of tissue
 Type of predominant necrosis in the tissue
Two MainType
DRY GANGRENE and
MOIST GANGRENE

4. DRY GANGRENE
Blood
content is
less
Fluid
content is
less
Necrosis
develops
slowly
Occur
in
tissue Legs
Hoof
Tail
Beak
Ear
Common
in
Fungus
(calviceps
purpuria)
Seleniferous
Plants
Feeding
Consistent
pressure on
skin
Causes
Moisture and temperature of the necrosed area are limiting factor for the growth & spread of putrefying bacteria.

5. DRY GANGRENE
GROSS APPEARANCE
Dry, shriveled & mummified appearance
Colour green to black
Zone of hyperemia and inflammation
putrid odour due to H2S
MICROSCOPIC APPEARANCE
Coagulative necrosis in affected area
Phagocytic leukocytes are predominant cell
pink stained with numerous bacteria
GIT is mostly involved, because intestinal wall gets necrosed easily by putrefactive bacteria and thereby rupture
occurs, and finally fecal content discharged in to peritoneal cavity and microorganisms spread rapidly into viscera.
Finally septicemia , toxemia shock & death occurs.

6. MOIST GANGRENE
Abundance of
Moisture
Higher
Temperature
VERY RAPID
growth of
saprophytic
bacteria
Occur
in
tissue
LUNGS
NTESTINE
Common in
INTERNAAL
ORGANS
Necrotizing
bacterial infection
(Clostridial
infection of soft
tissue)
Faulty drenching
of medicine
Intestinal
displacement
Causes
Death of individual is usual the result if moist gangrene is present. In such cases, animals dies of septicemia, toxemia and shock.

7. MOIST GANGRENE
GROSS APPEARANCE
Swelling, blistering & wet appearance
Green, Gray or black Colour due to H2S
Offensive odour
Numerous gas bubble within the tissue
No sharp line of demarcation between living and dead tissue
MICROSCOPIC APPEARANCE
Liquefactive necrosis is predominant type in affected area
Phagocytic leukocytes are predominant cell
pink stained with numerous putrefactive bacteria
Dried & shriveled part may undergo liquefaction with the passage of time and finally may cause sloughing of time
and finally cause sloughing of the affected tissue or area termed asVERTUAL AMPUTATION

8. THANKS