Wound Healing PDF

Wound healing Introduction  Definition:  The physiological process by which the body repairs tissue damage.  Types of Wounds:  Acute (e.g., surgical incisions)  Chronic (e.g., diabetic ulcers).  Goals of Healing:  Restoring tissue integrity and function; minimizing scarring. Phases  Hemo...

Wound healing Introduction  Definition:  The physiological process by which the body repairs tissue damage.  Types of Wounds:  Acute (e.g., surgical incisions)  Chronic (e.g., diabetic ulcers).  Goals of Healing:  Restoring tissue integrity and function; minimizing scarring. Phases  Hemostasis Phase  Duration: Immediate, lasting minutes to hours  Key Events:  Vasoconstriction to minimize blood loss.  Platelet aggregation forming a clot.  Release of clotting factors that establish a fibrin matrix.  Clinical Note: Patients with clotting disorders may have complications in this phase.  Inflammatory Phase  Duration: Begins within hours, lasting up to 3 days.  Key Events:  Recruitment of immune cells (neutrophils, macrophages) to the wound site.  Clearance of bacteria by neutrophils.  Release of cytokines and growth factors that initiate the repair process.  Signs: Redness, hotness, swelling, pain.  Clinical Note: Chronic inflammation (e.g., in diabetic wounds) impairs healing  Proliferative Phase  Duration: Starts around day 3-5, lasting up to 3 weeks.  Key Events:  Formation of granulation tissue:  Fibroblasts deposit collagen, creating a new extracellular matrix.  Angiogenesis: New blood vessels form to supply the healing tissue.  Epithelialization: Skin cells (keratinocytes) migrate to cover the wound.  Wound contraction: Myofibroblasts pull wound edges together.  Clinical Note: Excess collagen can lead to keloid or hypertrophic scars.  Maturation (Remodeling) Phase  Duration: Starts 3 weeks post-injury, lasts for months or even years.  Key Events:  Collagen remodeling: Type III collagen is replaced by stronger Type I collagen.  Reorganization of the tissue: Increases tensile strength of the wound.  Clinical Note: The wound site only regains 70- 80% of its original strength Types  Primary Intention: Edges are directly closed with minimal tissue loss (e.g., surgical incision), minimal scarring.  Secondary Intention:  Wound edges are not closed; healing occurs via granulation tissue formation (e.g., pressure ulcers).  Larger scar and takes longer to heal.  Tertiary Intention (Delayed Primary Closure):  Wound is initially left open to reduce infection risk, then closed surgically after a few days.   Systemic Factors  Age: Older slower  Reduced cell regeneration  Reduced immune function.  Nutrition: Protein, vitamin C, and zinc  Comorbidities: Diabetes impedes healing Factors  Poor blood flow affecting  Reduced immune response. wound  Medications:  Corticosteroids and immunosuppressants can slow healing down healing by dampening inflammation.   Local Factors  Infection:  Increase inflammatory response  Delay healing  Lead to chronic wounds. Factors  Oxygenation: affecting  Poor blood flow limits oxygen, essential for cell function in healing. wound  Foreign Bodies and Necrotic Tissue: healing  Must be removed to promote healing; debridement may be necessary.   Environmental Factors  Smoking:  Reduces blood oxygen levels and increases healing time.  Alcohol and Substance Use: Factors  Impairs immune function affecting  Reduces nutrient absorption. wound  Psychological Stress: healing  Chronic stress elevates cortisol, impairing wound repair.   Infection:  Seen in chronic wounds  Managed with antibiotics and wound care.  Dehiscence:  Separation of wound edges  Mechanical stress or infection Common  Requires reclosure. complications  Chronic Wounds:  Wounds that do not progress through normal healing stages  Common examples include diabetic foot ulcers and venous leg ulcers.   Assessment of Wound Healing: Regular evaluation  Interventions to Support Healing  Nutritional Support: Adequate protein and micronutrients.  Infection Control:  Wound cleansing Clinical management  Sterile techniques of wound  Antibiotic healing  Dressing Selection:  Appropriate dressings to maintain moisture balance and protect the wound.  Use of auxiliary Therapies  Negative Pressure Wound Therapy (NPWT):  Applies controlled suction to promote healing.  Hyperbaric Oxygen Therapy (HBOT):  Provides increased oxygenation to the wound.  Growth Factors and Skin Substitutes:  Used in chronic and difficult-to-heal wounds.  Hypertrophic scars  Definition  Raised, thickened scars that develop within the boundaries of the original wound.  Characteristics  Remain within the wound edges.  Red, raised, and may become itchy but usually improve over time.  Form due to excessive collagen deposition during the healing process, especially in the proliferative phase.  Causes and Risk Factors  Common after burns, surgical wounds, and other injuries with delayed healing.  More frequent in areas with high skin tension, like shoulders and chest.  Young age, darker skin, and genetics can increase risk. Treatment options  Treatment Options  Pressure Therapy: Compression garments can reduce scar thickness.  Silicone Gel Sheets: Applied to soften and flatten scars.  Corticosteroid Injections: Reduce inflammation and collagen production.  Laser Therapy: Improves appearance by reducing thickness and redness.  Surgical Revision: May be considered if other treatments are ineffective, though recurrence is possible.  Keloids  Definition  Overgrown scars that extend beyond the original wound boundaries, often forming a raised, thick, and fibrous tissue mass.  Characteristics  Extend beyond the wound edges and do not regress over time.  Can be itchy, painful, and may affect mobility depending on location.  Tend to grow larger than hypertrophic scars and may recur after removal.  Causes and Risk Factors  Result from abnormal wound healing and excessive collagen production.  Frequently seen in areas like the earlobes, chest, shoulders, and upper back.  Increased risk in individuals with darker skin, genetic predisposition, and younger age. Treatment options  Corticosteroid Injections: Common initial treatment to reduce size and symptoms.  Cryotherapy: Freezing keloid tissue, typically combined with other treatments.  Radiation Therapy: Used post-surgery to reduce recurrence risk.  Laser Therapy: Reduces redness and flattens keloid surface.  Surgical Excision: High recurrence risk; usually combined with other therapies, like radiation or corticosteroid injections. Differences Between Hypertrophic Scars and Keloids Feature Hypertrophic Scars Keloids Extend beyond the original Boundaries Stay within the wound edges wound edges Regression May improve over time Do not regress on their own Darker skin, genetic Risk Factors High tension areas, burns predisposition, younger age Symptoms Raised, may be itchy Raised, itchy, possibly painful Pressure therapy, silicone Corticosteroids, cryotherapy, Treatment sheets, corticosteroids radiation therapy MCQs  Which of the following is the first phase of wound healing?  A) Inflammatory phase  B) Proliferative phase  C) Hemostasis phase  D) Maturation phase  Answer: C) Hemostasis phase  During the inflammatory phase of wound healing, which cells arrive first at the wound site to begin clearing debris and bacteria?  A) Fibroblasts  B) Neutrophils  C) Myofibroblasts  D) Keratinocytes  Answer: B) Neutrophils  What is the main function of fibroblasts during the proliferative phase?  A) Release histamine to increase blood flow  B) Phagocytize bacteria and dead cells  C) Lay down collagen to form the extracellular matrix  D) Stimulate wound contraction  Answer: C) Lay down collagen to form the extracellular matrix  In wound healing, the replacement of Type III collagen with stronger Type I collagen primarily occurs during which phase?  A) Hemostasis  B) Inflammatory  C) Proliferative  D) Maturation  Answer: D) Maturation  Which of the following best describes healing by secondary intention?  A) Wound edges are approximated and sutured directly.  B) Wound is left open and heals through granulation tissue formation.  C) Wound is initially left open and closed surgically after a few days.  D) Wound edges are pulled together using skin grafts.  Answer: B) Wound is left open and heals through granulation tissue formation.  Which of the following systemic factors can delay wound healing?  A) Optimal hydration  B) Diabetes mellitus  C) Adequate protein intake  D) Wound dressing selection  Answer: B) Diabetes mellitus  A chronic wound typically fails to progress beyond which phase of healing?  A) Hemostasis  B) Inflammatory  C) Proliferative  D) Maturation  Answer: B) Inflammatory  The use of negative pressure wound therapy (NPWT) helps wound healing by which of the following mechanisms?  A) Increasing oxygenation directly to tissues  B) Reducing bacterial load and promoting granulation tissue  C) Providing additional nutrients to the wound  D) Stimulating blood clot formation  Answer: B) Reducing bacterial load and promoting granulation tissue  Which of the following nutrients is essential for collagen synthesis and thus important for wound healing?  A) Calcium  B) Vitamin D  C) Vitamin C  D) Potassium  Answer: C) Vitamin C  A patient with a post-surgical wound develops dehiscence. Which of the following is a likely cause?  A) Adequate blood flow  B) Infection at the wound site  C) Absence of scar formation  D) Presence of Type I collagen only  Answer: B) Infection at the wound site  Inadequate oxygen supply to a wound can impair healing by:  A) Increasing fibroblast activity  B) Reducing collagen synthesis and cellular activity  C) Enhancing angiogenesis  D) Preventing infection  Answer: B) Reducing collagen synthesis and cellular activity  Hyperbaric oxygen therapy (HBOT) aids in wound healing by:  A) Delivering high levels of oxygen to enhance healing  B) Removing necrotic tissue from the wound  C) Acting as an antibiotic for infected wounds  D) Directly stimulating keratinocyte migration  Answer: A) Delivering high levels of oxygen to enhance healing  In the maturation phase of wound healing, wound strength reaches about what percentage of its original tensile strength?  A) 100%  B) 90-95%  C) 70-80%  D) 50-60%  Answer: C) 70-80%  A wound with a significant amount of necrotic tissue may require which of the following interventions to promote healing?  A) Antibiotic ointment application  B) Debridement  C) Hyperbaric oxygen therapy  D) Vitamin supplementation  Answer: B) Debridement  Which cell type is primarily responsible for wound contraction during the proliferative phase?  A) Keratinocytes  B) Neutrophils  C) Myofibroblasts  D) Platelets  Answer: C) Myofibroblasts  Which of the following is TRUE about hypertrophic scars?  A) They grow beyond the boundaries of the original wound.  B) They are more likely to improve in appearance over time.  C) They typically require radiation therapy as a primary treatment.  D) They are painless and never cause itching.  Answer: B) They are more likely to improve in appearance over time.  Keloids are different from hypertrophic scars because they:  A) Stay within the boundaries of the original wound.  B) Regress over time and become less noticeable.  C) Extend beyond the original wound edges.  D) Form only in people with lighter skin tones.  Answer: C) Extend beyond the original wound edges.  Which of the following areas is at a higher risk for keloid formation?  A) Upper back and shoulders  B) Forearms  C) Lower legs  D) Abdomen  Answer: A) Upper back and shoulders  Which treatment option is most commonly used first for keloids?  A) Laser therapy  B) Cryotherapy  C) Surgical excision alone  D) Corticosteroid injections  Answer: D) Corticosteroid injections  A hypertrophic scar differs from a keloid because it:  A) Can extend beyond the wound margin  B) Remains confined to the original wound area  C) Is usually painless and colorless  D) Requires surgical removal  Answer: B) Remains confined to the original wound area  Which of the following is a common risk factor for developing keloids?  A) Advanced age  B) Use of corticosteroids  C) High skin tension areas and genetic predisposition  D) Light skin tone  Answer: C) High skin tension areas and genetic predisposition  Which therapy is often combined with surgical excision to reduce the recurrence of keloids?  A) Pressure therapy  B) Silicone gel sheets  C) Radiation therapy  D) Topical antibiotics  Answer: C) Radiation therapy  Which of the following statements is FALSE regarding hypertrophic scars?  A) They typically remain within the wound edges.  B) They can occur in response to delayed healing or high-tension areas.  C) They are more likely to appear in individuals with darker skin tones.  D) They do not improve in appearance over time.  Answer: D) They do not improve in appearance over time.  Which of the following treatments is often recommended to help flatten and reduce hypertrophic scars?  A) Cryotherapy  B) Silicone gel sheets  C) Antibiotic ointment  D) Wound debridement  Answer: B) Silicone gel sheets  Which of the following best describes the recurrence rate of keloids after surgical removal without adjunct therapy?  A) Low recurrence rate  B) High recurrence rate  C) No recurrence after complete removal  D) No difference with or without adjunct therapy  Answer: B) High recurrence rate  Which of the following is often a clinical feature of keloids but not typically of hypertrophic scars?  A) Confinement to the wound margins  B) Spreading beyond the wound area  C) Flattening over time  D) Formation immediately after injury  Answer: B) Spreading beyond the wound area  Which therapy is most commonly used to reduce redness and thickness in both hypertrophic scars and keloids?  A) Topical antibiotics  B) Radiation  C) Laser therapy  D) Negative pressure wound therapy  Answer: C) Laser therapy