Gangrene, introduction, definition, causes, symptoms, types, wet and dry gangrene, morphological features.

1. By: Nityanand Upadhyay
Associate Professor
Integral University, Lucknow

2.  A form of necrosis of tissue with
superadded putrefaction.
 The necrosis is usually coagulative
due to ischaemia.
 In all type of gangrene, necrosis
undergoes liquefaction by the
action of putrefactive bacteria.

3.  Putrefaction involves the decomposition of
proteins, breakdown of the tissues, and
liquefaction of the organs by the action of
microorganisms resulting in the production
of a foul smell.
 e.g. Staphylococcus(aerobic),
Clostridium(Anaerobic).

4.  Ischaemia- Lack of blood supply.
 Severe burns, scalds, and cold
 Raynaud’s disease:- There is impaired
circulation to the ends of fingers and toes,
especially in cold weather.
 Diabetes
 Injury
 Embolism
 Immune deficiency:

5.  Skin discoloration — ranging from pale to
blue, purple, black, bronze or red, depending
on the type of gangrene you have
 Swelling or the formation of blisters filled
with fluid on the skin
 A clear line between healthy and damaged
skin
 Sudden, severe pain followed by a feeling of
numbness
 A foul-smelling discharge leaking from a sore

6.  Thin, shiny skin, or skin without hair
 Skin that feels cool or cold to the touch
 The affected tissue is swollen and very painful
 A condition called septic shock can occur if a
bacterial infection that originated in the
gangrenous tissue spreads throughout your
body.

7.  Dry Gangrene
 Wet Gangrene
 Gas Gangrene

8.  This form of gangrene begins in
the distal part of a limb due to
ischaemia.
 The typical example is the dry
gangrene in the toes and feet of
an old patient due to
arteriosclerosis.

10.  The affected part is dry, shrunken and dark
black, resembling the foot of a mummy.
 It is black due to liberation of haemoglobin
from haemolysed red blood cells which is
acted upon by hydrogen disulfide (H2S)
produced by bacteria resulting in formation of
black iron sulfide.
 The line of separation usually brings about
complete separation with eventual falling off of
the gangrenous tissue if it is not removed
surgically.

11.  Naturally moist tissues and organs such as the
mouth, bowel, lung, cervix, vulva.
 Develops rapidly due to blockage of venous, and
less commonly, arterial blood flow from
thrombosis or embolism.
 The affected part is stuffed with blood which
favours the rapid growth of putrefactive bacteria.
 The toxic products formed by bacteria are
absorbed causing profound systemic
manifestations of septicaemia, and finally death.

12.  Diabetic foot – high sugar
content in
the necrosed tissue which
favours growth of
bacteria.
 Bed sores – bed-ridden
patient due to pressure
on sites like the sacrum,
buttocks and heels

14.  The affected part is soft, swollen, putrid,
rotten and dark.
 The classic example is gangrene of bowel,
commonly due to strangulated hernia,
volvulus or intussusception.
 The part is stained dark due to the same
mechanism as in dry gangrene.

16.  Special form of wet gangrene caused by gas-
forming clostridia (gram-positive anaerobic
bacteria).
 Gain entry into the tissues through open
contaminated wounds.
 Such as in the muscles, or as a complication
of operation on colon which normally
contains clostridia.
 It produce various toxins which produce
necrosis and oedema locally.
 Also absorbed producing profound systemic
manifestations.

18.  The affected area is swollen, oedematous,
painful and crepitant due to accumulation of
gas bubbles within the tissues.
 Subsequently, the affected tissue becomes
dark black and foul smelling.

19. THANKS……