Gangrene - Definition and their types

1. GANGRENE
By
Rohini Surti
BPT 2NDYEAR

2. INTRODUCTION :
• Gangrene is necrosis of tissue associated with Suporadded putrefaction
most often following coagulative necrosis due to ischaemia.
• Gangrenous /necrotising inflammation is characterised primary by
inflammation of provoked by virulent bacteria resulting in massive tissue
necrosis.
• Examples of necrotising inflammation are gangrenous appendicitis and
gangrenous stomatitis.

3. TYPES OF GANGRENE :
1. Wet Gangrene
2. Dry Gangrene
3. Gas Gangrene
Generally,there are two types of gangrene wet and dry and A variant
Gangrene is called Gas Gangrene.

4. 1.WET GANGRENE :
• It occurs naturally in many tissue and organs such as bowel, lungs, mouth, cervix,vulva,etc.
• Clinical significance are:Diabetic foot, they have high content of sugar provide more bacterial
growth.
Bed sores occurring in a bed ridden Patient due to pressure on sites like sacrum,buttocks and heels.
• It develops due to blockage of both venous & arterial blood flow.
• The affected part is stuffed with blood which favours rapid growth of putrefaction bacteria.
• Toxic products formed by bacteria are absorbed causing profound systemic manifestation and
finally death.

5. Morphologic fractures :
• Grossly:The affected part is soft, swollen, putrid,rotten,and dark. Ex.Gangrene of bowel,
commonly due to strangulated hernia, volvulus.The part is stained dark black due to same
mechanism as in dry gangrene .
• Histologically:There is coagulative necrosis with stuffing of affected part with blood.
Mucosa will be ulcerated and sloughed.
lumen of bowel contains mucus and blood.There is intense acute inflammatory exudates
and thrombosed vessel.
The line of demarcation between gangrenous and viable bowel is generally not clear cut.

7. 2.DRY GANGRENE :
• This begins from distal part of limb due to ischaemia.
• The typical Exmaples is dry gangrene in toe and feet of an old patient due to severe
atherosclerosis.
• It is usually intaited in one of the toes which is farthest from the blood supply,containing
so little blood that even the invading bacteria find it difficult to grow in the necrosed area.
• Gangrene grows slowly upward until reaches a point where blood supply is adequate to
keep tissue viable.

8. Morphologic features :
• Grossly:The affected part is dark black,resembling the foot of a mummy.It is black due
to liberation of hemoglobin from haemolysed rbc which is acted upon hydrogen
disulphide produced by bacteria resulting in formation of black iron sulfide.
The line of separation usually brings about complete separation with eventual falling off
the granulation tissue,if not removed surgically.
• Histologically : There is necrosis with smudging of the tissue.Line of separation
consist of inflammatory granulation tissue.

10. 3.GAS GANGRENE :
• It is special form of Wet Gangrene caused by gas forming clostridia.
• It gains entry through tissue of open contaminated wounds,especially in muscles,colon
operation
• Clostridia produce various toxins which produce necrosis and oedema locally and are
absorbed producing profound systemic menifestations.

11. Morphologic features :
Grossly:The affected part is swollen, oedmatous,painful,and criptant due to accumulation
of gas bubbles of CO2 within tissue formed by fermentation of sugars by bacterial toixns.
So it becomes dark black & foul smelling.
• Microscopically :The muscles fibres undergo coagulative necrosis can be identified.At
periphery,a zone of leucocytic infiltration,oedema and congestion are found.

13. THANKYOU

14. REFERENCE :
•Harsh Mohan PathologyTextbook 7th
edition