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Ch 9 Inflammation Lecture

Inflammation Overview

  • Introduction to Inflammation
    • Source: Chapter nine of the textbook.
    • Closely related to immunity, which will be discussed in a separate lecture.

Innate Immunity

  • Definition:

    • Innate immunity is the immunity that individuals are born with.
    • It reacts consistently to antigens without alteration regardless of exposure frequency.

  • Characteristics:

    • Present at birth; an innate response.
    • Goals:
      • To limit and control the inflammatory process.
      • To prevent and limit infection or damage.
      • To initiate adaptive immune responses.
      • To assist in the healing process.

Types of Inflammation

  • Acute Inflammation:

    • Characteristics:
      • Self-limited; duration from hours to days, not permanent.
      • Rapid occurrence following cell injury.

  • Chronic Inflammation:

    • Definition:
      • Unsuccessful acute response.
    • Characteristics:
      • Considered a dysfunction of inflammation.
      • Results in inhibition of healing, cellular damage, and organ dysfunction.

Cardinal Signs of Inflammation

  • Five cardinal signs:
    1. Erythema (redness)
    2. Heat
    3. Swelling
    4. Pain
    5. Loss of function
  • Example Demonstration:
    • Context: Injury from a splinter or cut.
    • Relation: Swelling correlates with loss of function; e.g., joint movement limitation due to swelling.

Wound Healing Process

  • Introduction to Wound Healing:

    • Inflammation plays a significant role in the healing process.

  • Describing Wound Drainage:

    • Importance of using medical terminology rather than colloquial terms for wound descriptions.
    • Types of drainage:
      • Serous/Transudate: Watery exudate indicating early inflammation.
        • Example: Clearish drainage from minor cuts, potentially yellow-tinged.
      • Sanguineous: Presence of blood in drainage.
      • Serosanguinous: A mixture of clear and blood-stained drainage.
      • Purulent: Contains pus, indicative of bacterial infection.

Steps in Normal Wound Healing

  1. Hemostasis:

    • Process to stop bleeding involving:
      • Platelets, serotonin, histamine, and epinephrine.
      • Functions: Blood clotting, vasoconstriction, inflammation.

  2. Inflammatory Phase:

    • Vasodilation occurs to limit blood loss and contain pathogens.
    • Inflammation allows for immune system response.

  3. Proliferation and Granulation:

    • Formation of granulation tissue, angiogenesis (new artery growth), and epithelialization (new cell growth).
    • Scar formation:
      • Scar tissue is usually different from the original tissue structure.
      • Potential loss of sensation in scarred areas.

  4. Wound Contraction and Remodeling:

    • Occurs after about three weeks post-injury where the body reshapes and refines scar tissue.

Types of Wound Healing

  • Primary Intention:

    • Ideal healing process.
    • Characteristics:
      • Clean, approximated edges with minimal or no scarring.
      • Example: Clean-cut surgical wounds.

  • Secondary Intention:

    • Involves excessive tissue loss requiring regeneration.
    • Results in scar formation.

  • Tertiary Intention:

    • Undesired healing type.
    • Characteristics:
      • Deep tissue missing, and often infected.
      • Left open for drainage before closure.

Factors Influencing Wound Healing

  • Nutrition:

    • Protein is crucial; lack thereof can lead to impaired healing.

  • Oxygen:

    • Essential for repair; hyperbaric chambers can provide necessary oxygen for severely injured wounds.

  • Circulation:

    • Adequate blood circulation is necessary to prevent ischemia or infarction affecting wound healing.

  • Immune Strength:

    • Factors such as diabetes, steroid use, and cancer can compromise immunity, impacting healing efficacy.

  • Contamination:

    • Foreign bodies can impede healing.
    • Surgical devices can become contaminated.

  • Mechanical Factors:

    • Increased local pressure, excessive tissue, etc., can hinder healing.

  • Age:

    • Regenerative ability varies; wounds heal faster in infants compared to elderly individuals.

Dysfunctional Wound Healing

  • Definition:

    • Wounds that do not heal properly.

  • Causes:

    1. Ischemia
    2. Excessive bleeding
    3. Excessive fibrin deposits
    4. Underlying health issues (e.g., diabetes, obesity, infection).
    5. Drug usage and smoking; the latter causes vasoconstriction and reduces blood oxygenation.

Complications of Wound Healing

  • Hyperplasia:

    • Overgrowth of scar tissue leading to keloids, more prevalent in individuals of African descent.

  • Contractures:

    • Inflexible shrinkage of tissue affecting movement range.

  • Dehiscence:

    • Wound opening along the suture line, risking complications.

  • Evisceration:

    • Severe wound opening where organs protrude; requires immediate covering with saline gauze and surgical intervention.

  • Stricture:

    • Abnormal narrowing of body passages causing functional issues (e.g., esophageal stricture).

  • Fistula:

    • Abnormal connection between body areas (e.g., between rectum and bladder) leading to infections.

  • Adhesions:

    • Internal scar tissue between organs, causing complications within the body (refer to internal keloids).

  • Visual Aids:

    • Presentation includes images illustrating keloid formation and types of wound closures.