WOUNDS
SKINIt is the outer envelope of the body. Is the largest organ of the body. It measures about 2 square meter surface area. The anatomical features, including its thickness, amount of dermis , hair distribution and number of its appendages, and pigmentation of skin are variable from one area to another.
It is composed of two layers;Epidermis: the outer layer , consists of keratinized stratified Squamous epithelium arranged in five layers; stratum basali, stratum granulosum, stratum spinosum, stratum, stratum cornium, stratum lucidum. There are four main types;1-Keratenocyte, the structural cells.2-Melanocytes, the pigment cells.3-Merckel cells, sensation.4-Langhan’s cells immune cell.
Dermis: the inner layer, arranged in two layers an outer papillary( more vascular, more sensitive, less fibrous) and inner (less vascular, less sensitive, more fibrous) consists of connective tissue and contain five main elements;1-Ground substance.2-Cells; different types like fibroblasts, mast cells, mesenchymal cells, etc…3-Fibers, mainly collagen, and elastin.4-Skin appendages; sweat glands and Pilosebaceous apparatus. 5-Vessels and nerves.
Functions of skin:1.Protection against physical, mechanical, and biological traumas.2.Appearance3.Thermoregulation4.Metabolic.
Wound: break in tissue continuity.Types:A-Acute wounds:1.Contusions and bruises result from blunt trauma Characterized by internal bleeding and hematoma.2.Abrasive wounds, superficial wounds involving the epidermis and outer layer of dermis, healed by method of partial thickness wound healing process.3.Incision wounds. Traumatic and iatrogenic, depth is less than length.
4.Penetrating wounds their depth is more than length, including different types; puncture, stab and perforating wounds.5.Laceration wounds usually multiple and parallel, and oblique in direction.6.Crush wounds; result from trauma by heavy object with high velocity and associated injury to deeper tissues.7.Avulsion wounds. associated with separation or loss of tissue at the of an avascular plain loose areolar tissue 8.Bites including insect bites, animal and human bites. Human bite is more contamining than animal bite.
b-Chronic wounds like; leg and foot ulcers ( varicose , diabetic, ischemic, etc….). pressure ulcer, malignant ulcers , chronic discharging sinuses and fistulas, etc…
Clinical features:1.Pain.2.Bleeding.3.Deformities.4. Symptoms and signs of inflammations like; Swelling (edema), redness, hotness, tenderness.5.Manifestations of deeper tissue injuries.
Wound healing: is the process of repair of tissue.Steps of wound healing include:1. Inflammatory phase: 0-4days.A)Vascular; Vasoconstriction early for few minutes to stop bleeding,, and vasodilatation result in increased blood at wounded site which is responsible for the symptoms and signs of inflammation like redness, swelling, hotness, tenderness, and tenderness.
B)Cellular; platelets are the first reaching to the wounded area, play a rule in hemostasis and release factor that promote wound healing process Neutrophiles Reach the wounded area within the first 48 hours and as a phagocytic cells only. Macrophages are modified monocytes and are the dominant cells at the wound site at the end of inflammatory phase. Their functions are phagocytosis, releases of factors that control wound healing, and antigen processing.Lymphocyte are chronic inflammatory cells and reached late in this phase.
2. Proliferative phase: 5-21 days, characterized by formation of granulation tissue and collagen fibers deposition. Granulation is a connective tissue composed of capillaries, fibroblasts and collagen fibers 3. Remodeling phase: 21 days-six months, maturation of scar.
Types of wound healings:Primary intention when the wound margins are closely approximated as in incisional wounds, there will be minimal collagen deposition and scar formation, and epithelialization completed within 24-48 hours.
Secondary intention: when there is a gap between the wound margin as in full thickness wounds, third degree burn and ulcers, epithelialization will be delayed and there will be prolonged Proliferative phase, more granulation tissue formation and scar deposition. Wound contraction is process by which the wound size decreases and mediated by myofbroblasts. Myofbroblasts are star shaped cells contain actin fibrils and release collagen. Contracture is the end result of wound contraction process.
Healing of partial thickness wound; as in abrasive wounds, second degree burn and donor sites of split thickness skin graft, characterized by less scar formation and epithelialization from wound margins and skin appendages in the base of the wound.
1.Factors affecting wound healing:A-Systemic factors;1.Nutrition as proteins, carbohydrates (calories), fat, Vitamins, minerals, and trace elements.2.Age.3.Systemic diseases; Anemia, Diabetes mellitus, systemic acute and chronic infections, neoplastic diseases, uremia, jaundice, etc….4.Associated traumas.
B-Local factors:1. Site. 2. Size.3. Shape.4. Local circulation. 5. Edema. 6. Infection. 7. Foreign bodies.8. Trauma. 9. Irradiation. Etc…
Management:History: Cause, Mechanism , duration, symptoms, etc…Clinical examination: -Local site, shape, size, type, injury to the deeper stractures,etc….-Systemic as manifestation of shock, associated trauma,etc….Investigations hematological as blood grouping , radiological as X ray, CT scan, MRI and Ultrasonagraphy
Treatment: 1. Hemostasis. 2. Cleaning as wash. 3. Debridment (wound excision). 4. Wound closure (with consideration of repair of deeper tissue injuries). 5.Dressing: consist of Greased gauze, dry gauze, cotton, bandages and adhesive tapes according to the site, shape and type of the wounds. The aims and functions of dressing include: a. Protection against traumas. b. Immobilization.c. Pressure for hemostasis.d. Absorption.e. Appearance.