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Wound

  • Introduction

    • Wound is discontinuity or break in surface epithelium

    • Simple when only skin is involved

    • Complex when it involves underlying nerves, vessels and tendons

  • Types of wounds

    • Closed Wound

      • Contusion

        • Minor soft tissue injury without break in skin

        • It produces discoloration of skin due to collection of blood underneath


      • Abrasion

        • Epidermis of skin is scraped away exposing dermis

        • Painful, as dermal nerve endings are exposed


      • Hematoma

        • Collection of blood following injury

        • It can be subcutaneous, intramuscular, subperiosteal

        • They get absorbed, if not they get infected



    • Open Wound

      • Incised Wound

        • Caused by sharp objects

        • Has sharp edge and it is less contaminated

        • Primary suturing is ideal


      • Lacerated Wound

        • Caused by blunt injuries

        • Due to blunt nature of object, there is crushing of tissue which may result in hematoma, bruising or even necrosis of tissue


      • Penetrating wound

        • Look like innocent injury with small, 1 or 2 cm long cut but internal organs such as intestines, liver, spleen or mesenteric blood vessels may have been damaged


      • Crushed or Contused wounds

        • Caused by blunt trauma

        • May cause severe hemorrhage, death of tissue and crushing of blood vessels.

        • More prone to gas gangrene, tetanus



    • Tidy Wounds

      • Incised, clean, healthy tissue

    • Untidy Wounds

      • Crushed or avulsed, contaminated, devitalised tissue and often with tissue loss

    • Acute Wound

      • Stab wound, blast injuries, RTA

    • Chronic Wound

      • Leg ulcers, pressure sore


  • Healing of wound

    • By primary intention- Produces clean, neat, thin scar

    • By secondary intention- Produces ugly scar


  • Components of wound healing

    • Inflammatory phase (Lag Phase)

      • Release of mediators of inflammation like histamine from platelets, mast cells and granulocytes. This causes increase capillary permeability

      • Later kinins and prostaglandins act and they play a chemotactic role for white cells and fibroblasts

      • In first 48 hours, polymorphonuclear leukocytes dominate. They play role of scavengers by removing dead and necrotic tissue



    • Proliferative Phase (Collagen Phase)

      • Between 3rd and 5th day, polymorphonuclear leukocytes diminish and monocytes increase. They are specialized scavengers

      • By 5th and 6th day, fibroblast appear, proliferate and eventually give rise to protocollagen which is converted in collagen

      • Enzyme protocollagen hydroxylase, oxygen, ferrous ions and ascorbic acid are necessary for this step

      • Epithelialisation occurs from edges of wound by process of cell migration and cell multiplication by marginal basal cells. Within 4 hours entire wound is re-epithelialised



    • Remodelling Phase (Maturation)

      • Starts after 4th day and completed by 14th day

      • Brought by specialised fibroblast called as myofibroblasts

      • Corticosteroids, irradiation, chemotherapy delay wound contraction



    • Phase of Scar formation

      • Fibroplasia and laying of collagen is increased

      • Vascularity become less

      • Epithelialisation continues

      • Ingrowth of lymphatics and nerve fibres takes place

      • Remodelling of collagen takes place with cicatrisation, resulting in a scar


  • Complication of wound healing

    • Infection- Majority of bacteria are endogenous

    • Ugly scar

    • Keloid and hypertrophic scar

    • Incisional Hernia and wound dehiscence

    • Pigmentation

    • Marjolin's ulcer


  • Wound closure or wound suturing

    • Primary suturing-

      • Within few hours

      • It should be incised or cut wound

      • There should not be any infection

      • Foreign body if present should be removed

      • Associated injuries to other structure should be repaired

      • Injection TT should be given



    • Wound excision and primary suturing

      • When wounds edges are jagged

      • Wound is contaminated with organisms or foreign body

      • Tissue are crushed

      • In such conditions, wound is explored and devitalised tissues and foreign body if present are removed. The wound is irrigated with antiseptic agents.

      • Precautions

        • Done within 6 hours

        • Tetanus and gas gangrene prophylaxis

        • Repair of tendons and nerves can be done at later date if contamination is excessive



    • Wound excision and delayed primary suturing

      • Indicated in lacerated wounds with major crush injuries.

      • Primary suturing within 6 hours is not done in these wounds because of

        • Gross oedema

        • Increased tissue tension

        • Hematoma

        • Contamination with bacteria

      • Principles of debridement

        • Done under General Anaesthesia

        • Assess the extent of injuries and loss of tissue

        • Control bleeding

        • Excision of devitalised tissue

        • Good saline wash than betadine and hydrogen peroxide

      • Complication of skin loss

        • Secondary infection

        • Underlying structures are in danger

        • Septicemia

        • Deformity and disability in later date



    • Secondary Suturing

      • Suturing after 7 to 14 days later after controlling infection

      • Skin is freed from the edges of the wound and the granulation tissue and skin are approximated


  • Factors affecting wound healing

    • General factors

      • Age

        • Dermal collagen content decrease with aging

        • Collagen fibres show distorted architecture and organisation on aging

      • Malnutrition

        • Delayed because of deficiency of vit C

          • It is important for synthesis and maintenance of collagen

          • Following injury vitamin C deficiency can occur after 3 to 4 weeks

        • Zinc deficiency is known to delay the healing of pilonidal sinus

        • Albumin levels must be less than 2 g/dL to have an effect on wound healing

      • Diabetic Patient

        • Due to microangiopathy, atherosclerosis, decreased phagocytic activity and proliferation of bacteria

      • Jaundice and uraemic patient

        • Fibroblastic repair is delayed

      • Cytotoxic drug like doxorubicin

      • Malignancy

        • Chemotherapeutic drug causes

          • Decreased mesenchymal cell proliferation

          • Reduce number of platelets

          • Reduced inflammatory cells

          • Reduce growth factors

          • Decrease wound breaking strength

      • Generalised infection

      • Corticosteroids

        • If given early after healing they do no interfere



    • Local Factor

      • Poor blood supply

        • Wound on knee and shin of tibia

      • Local infection

        • If bacteria count exceeds 10,0000 organism/ mg and if beta hemolytic streptococci are present then wound does not heal

        • Collagen synthesis is reduced and collagenolysis is increased

      • Hematoma

      • Faulty technique

      • Tension

      • Hypoxia

        • Killing property of macrophages reduced

        • Production of fibroblasts reduced

        • Collagen synthesis affected

        • Smoking causes vasoconstriction and elevate carbon monoxide level

      • Ionizing radiation


  • Hypertrophic Scar


    • Hypertrophy of mature fibroblasts in hypertrophic scar.

    • Occurs from prolonged inflammatory phase

    • No itching

    • Non tender

    • Not vascular

    • Does no extend beyond the boundary of original incision or wound

    • Precipitating Factor

      • Over Sternum

      • Over Joints

      • Young person

    • Treatment

      • Often not necessary

      • Stocking, gloves

      • Elastic bandage

      • Excision can be done

      • Topical retinoids


  • Keloids


    • In keloid, proliferation of immature fibroblasts with immature blood vessels are found

    • Collagen bundle are virtually absent

    • Marked tendency for local recurrence after excision

    • Common site- Over Sternum

    • Continue to get worse even after 1 year

    • Severe itching

    • Margin is tender

    • Vascular red and erythematous

    • Precipitating factors

      • Generally in black races

      • Tuberculosis patient

      • Hereditary

      • Vaccination sites

      • Does not become small

    • Complication

      • Ulceration

      • Infection

    • Treatments

      • Injection Kanacort

      • Intrakeloidal excision and skin grafting

      • Silicone application

      • Topical retinoids

    • Keloid Sites

      • High chances

        • Skin of ear lobe

        • Presternal

        • Deltoid

        • Upper back

      • Least Chances

        • Eyelid

        • Genitalia

        • Palm

        • Sole

        • Across joint


  • Response to injury

    • Depends upon severity of injury

    • Neuroendocrine response

      • Earliest to get activated

      • Starts with nociceptive receptors

      • Stimulation of hypothalamus leads to release of corticotrophin releasing hormone (CRH), which triggers release of ACTH from anterior pituitary.

      • ACTH act on adrenals to increase the secretion of cortisol.

      • Activation of sympathetic nervous system, which in turn causes release of adrenaline and glucagon

      • Increased release of growth hormone and glucagon



      • Hormones which increase following injury

        • ACTH

        • GH

        • Glucagon

        • Cortisol

        • Adrenaline

      • Hormone whose level fall following inury

        • Insulin

        • Thyroid hormones

        • Testosterone



    • Immune response

      • Pro inflammatory response

        • Causes

          • Pyrexia, due to action of pro inflammatory cytokines on hypothalamus

          • Proteolysis in skeletal muscles

          • Production of acute phase protein in liver

        • Pro inflammatory cytokines

          • IL- 1

          • IL- 6

          • IL- 8

          • TNF alpha

      • Anti inflammatory response

        • Anti inflammatory cytokines

          • IL- 4

          • IL- 5

          • IL- 9

          • IL- 13

          • TNF Beta




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