PATHOPHYSIOLOGY OF HEALING WITH PRIMARY & SECONDARY INTENTION.pptx

This presentation deals with Pathophysiology of healing & Mechanism of repair with Primary Intention and Secondary intention

1. PATHOPHYSIOLOGY OF HEALING WITH PRIMARY AND SECONDARY INTENTION AND REPAIR MECHANISM Dr Akshay Shetty Associate Professor SSRAMC & H Inchal

2. Contents Objectives Definition of Healing Pathophysiology of healing Primary intention Secondary intention Summary References 20/01/2024 PATHOPHYSIOLOGY OF HEALING WITH PRIMARY AND SECONDARY INTENTION AND REPAIR MECHANISM(Dr Akshay Shetty) 2

3. Objectives By the end of the presentation the students must be able to – Define Healing Illustrate Pathophysiology of healing & Repair Mechanism Describe Primary intention Explain Secondary intention 20/01/2024 PATHOPHYSIOLOGY OF HEALING WITH PRIMARY AND SECONDARY INTENTION AND REPAIR MECHANISM(Dr Akshay Shetty) 3

4. HEALING Injury to tissue may result in cell death and tissue destruction. Healing on the other hand is the body response to injury in an attempt to restore normal structure and function. 20/01/2024 PATHOPHYSIOLOGY OF HEALING WITH PRIMARY AND SECONDARY INTENTION AND REPAIR MECHANISM(Dr Akshay Shetty) 4

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6. Regeneration & Repair 20/01/2024 PATHOPHYSIOLOGY OF HEALING WITH PRIMARY AND SECONDARY INTENTION AND REPAIR MECHANISM(Dr Akshay Shetty) 6

7. Cell cycle is defined as the period between two successive cell divisions and is divided into 4 unequal chases: M (mitosis) phase: phase of mitosis. G1, (gap i ) phase: The daughter cell enters G1, phase after mitosis. S (synthesis) phase: During this phase, the synthesis of nuclear DNA takes place. G2, (gap 2) phase: After completion of nuclear DNA duplication, the cell enters G, phase. G0, (gap 0) phase: This is the quiescent or resting phase of the cell after an M phase. 20/01/2024 PATHOPHYSIOLOGY OF HEALING WITH PRIMARY AND SECONDARY INTENTION AND REPAIR MECHANISM(Dr Akshay Shetty) 7

8. Not all cells of the body divide at the same pace. Some mature cells do not divide at all while others complete a cell cycle every 16-24 hours. The main difference between slowly-dividing and rapidly-dividing cells is the duration of G, phase. Depending upon their capacity to divide, the cells of the body can be divided into 3 groups: Labile cells Stable cells Permanent cells. 20/01/2024 PATHOPHYSIOLOGY OF HEALING WITH PRIMARY AND SECONDARY INTENTION AND REPAIR MECHANISM(Dr Akshay Shetty) 8

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12. RELATIONSHIP OF PARENCHYMAL CELLS WITH CELL CYCLE 20/01/2024 PATHOPHYSIOLOGY OF HEALING WITH PRIMARY AND SECONDARY INTENTION AND REPAIR MECHANISM(Dr Akshay Shetty) 12

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15. REPAIR 20/01/2024 PATHOPHYSIOLOGY OF HEALING WITH PRIMARY AND SECONDARY INTENTION AND REPAIR MECHANISM(Dr Akshay Shetty) 15

16. WOUND HEALING 20/01/2024 PATHOPHYSIOLOGY OF HEALING WITH PRIMARY AND SECONDARY INTENTION AND REPAIR MECHANISM(Dr Akshay Shetty) 16

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18. Healing by First Intention (Primary Union) 20/01/2024 PATHOPHYSIOLOGY OF HEALING WITH PRIMARY AND SECONDARY INTENTION AND REPAIR MECHANISM(Dr Akshay Shetty) 18

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20. EPITHELIAL CHANGES . The basal cells of epidermis from both the cut margins start proliferating and migrating towards incisional space in the form of epithelial spurs. A well-approximated wound is covered by a layer of epithelium in 48 hours. The migrated epidermal cells separate the underlying viable dermis from the overlying necrotic material and clot, forming scab which is cast off. The basal cells from the margins continue to divide. By 5th day, a multilayered new epidermis is formed which is differentiated into superficial and deeper layers. 20/01/2024 PATHOPHYSIOLOGY OF HEALING WITH PRIMARY AND SECONDARY INTENTION AND REPAIR MECHANISM(Dr Akshay Shetty) 20

21. ORGANISATION . By 3rd day, fibroblasts also invade the wound area. By 5th day, new collagen fibrils start forming which dominate till healing is completed. In 4 weeks, the scar tissue with scanty cellular and vascular elements, a few inflammatory cells aid epithelialized surface is formed. 20/01/2024 PATHOPHYSIOLOGY OF HEALING WITH PRIMARY AND SECONDARY INTENTION AND REPAIR MECHANISM(Dr Akshay Shetty) 21

22. SUTURE TRACKS . Each suture track is a separate wound and incites the same phenomena as in healing of the primary wound i.e. filling the space with haemorrhage, some inflammatory cell reaction, epithelial cell proliferation along the suture track from both margins, fibro- blastic proliferation and formation of young collagen. . 20/01/2024 PATHOPHYSIOLOGY OF HEALING WITH PRIMARY AND SECONDARY INTENTION AND REPAIR MECHANISM(Dr Akshay Shetty) 22

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24. Healing by Second Intention (Secondary Union) 20/01/2024 PATHOPHYSIOLOGY OF HEALING WITH PRIMARY AND SECONDARY INTENTION AND REPAIR MECHANISM(Dr Akshay Shetty) 24

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27. Epithelial changes. As in primary healing, the epidermal cells from both the margins of wound proliferate and migrate into the wound in the form of epithelial spurs till they meet in the middle and re- epithelialise the gap completely. However, the proliferating epithelial cells do not cover the surface fully until granulation tissue from base has started filling the wound space. In this way, pre-existing viable connective tissue is separated from necrotic material and clot on the surface, forming scab which is cast off. In time, the regenerated epidermis becomes stratified and keratinised. 20/01/2024 PATHOPHYSIOLOGY OF HEALING WITH PRIMARY AND SECONDARY INTENTION AND REPAIR MECHANISM(Dr Akshay Shetty) 27

28. Granulation tissue. The main bulk of secondary healing is by granulations. Granulation tissue is formed by proliferation of fibroblasts and neovascularisation from the adjoining viable elements. The newly-formed granulation tissue is deep red, granular and very fragile. With time, the scar on maturation becomes pale and white due to increase in collagen and decrease in vascularity. The specialised structures of skin like hair follicles and sweat glands are not replaced unless their viable residues remain which may regenerate. 20/01/2024 PATHOPHYSIOLOGY OF HEALING WITH PRIMARY AND SECONDARY INTENTION AND REPAIR MECHANISM(Dr Akshay Shetty) 28

29. Wound contraction. Contraction of wound is an important feature of secondary healing, not seen in primary healing. Due to the action of myofibroblasts present in granulation tissue, the wound contracts to one-third to one-fourth of its original size. Wound contraction occurs at a time when active granulation tissue is being formed. Presence of infection. Bacterial contamination of an open wound delays the process of healing due to release of bacterial toxins that provoke necrosis, suppuration and thrombosis. Surgical removal of dead and necrosed tissue, debridement, helps in preventing the bacterial infection of open wounds 20/01/2024 PATHOPHYSIOLOGY OF HEALING WITH PRIMARY AND SECONDARY INTENTION AND REPAIR MECHANISM(Dr Akshay Shetty) 29

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32. Summary 20/01/2024 PATHOPHYSIOLOGY OF HEALING WITH PRIMARY AND SECONDARY INTENTION AND REPAIR MECHANISM(Dr Akshay Shetty) 32

33. References Harsh Mohan Text Book of Pathology https://youtu.be/G3B0ApUsYag?feature=shared 20/01/2024 PATHOPHYSIOLOGY OF HEALING WITH PRIMARY AND SECONDARY INTENTION AND REPAIR MECHANISM(Dr Akshay Shetty) 33

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