Gangrene

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

1. Gangrene 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. Definition

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). Putrefying Bacteria

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 : Causes

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 Symptoms

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. Symptoms

7. Types of Gangrene 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. Dry Gangrene

9. 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. Morphological Features

10. 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. Wet Gangrene

11. Wet Gangrene 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

12. Wet gangrene Intestine

13. 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. MORPHOLOGICAL FEATURES

14. Contrasting Features of Dry and Wet Gangrene

15. 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. GAS GANGRENE

16. GAS GANGRENE

17. 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 . MORPHOLOGICAL FEATURES

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