Inflammation Response and Complications

Inflammation Response

• Inflammation is a non-specific response to harmful stimuli aimed at reducing damage

• Inflammation can be caused by various agents, including injuries, infections, autoimmune diseases, pathogens, damaged cells, and irritants like cigarette smoke.

• Inflammation is a protective process that typically stimulates healing and prevents further damage

• Occasional discomfort from inflammation often resolves with palliative care

Complications of Inflammation

• Inflammation can escalate and lead to complications like autoimmune disorders.

• Examples of autoimmune disorders linked to inflammation include rheumatoid arthritis (RA), psoriasis, systemic lupus erythematosus (SLE), and Guillain-Barré syndrome.

• Autoimmune disorders may require more aggressive care, including pharmacotherapy.

Inflammation

• Inflammation is a body's natural response to injury or illness
• Inflammation is the first step in the healing process
• Inflammation brings fluid, dissolved substances, and blood cells to the injured area.
• This response is non-specific, meaning the same events occur regardless of the cause of the inflammation.
• Inflammation is designed to neutralize and eliminate invaders, remove damaged tissue, and start healing and repair.
• Inflammation can be caused by: microorganisms, chemical agents, and physical agents
• Microorganisms that cause inflammation include: bacteria, viruses, fungi, helminths, and protozoans
• Chemical agents that cause inflammation include: internal substances like hydrochloric acid and external substances like poisons
• Physical agents that cause inflammation include: trauma to the skin, excessive heat or cold, and radiation.
• Disorders involving inflammation usually end in "-itis". Examples include: bronchitis, colitis, and gastritis.
• There are five common signs of inflammation:
  • Erythema (redness)
  • Heat
  • Swelling
  • Pain
  • Impaired function (potential)

Inflammation

• The inflammatory process protects the body by isolating damaged areas and promoting repair.
• Inflammation can be acute or chronic.
• Acute inflammation occurs within minutes to hours after an injury, infection, or other harmful stimulus.
• Five key signs of acute inflammation are redness, heat, swelling, pain, and impaired function.
• Acute inflammation resolves when the harmful stimulus is neutralized.
• Mast cells release chemical mediators (histamine, bradykinin, complement, and leukotrienes) during acute inflammation.
• These mediators cause:
  • Vasodilation (redness and heat)
  • Vascular permeability (edema)
  • Cellular infiltration (pus)
  • Thrombosis (clots)
  • Stimulation of nerve endings (pain)
• Chronic inflammation can occur when acute inflammation fails to neutralize the harmful stimulus.
• Chronic inflammation can persist for months or years.
• Chronic inflammation can be caused by various factors such as seasonal allergies, autoimmune diseases, and persistent infections.
• Chronic inflammation does not usually follow acute inflammation.
• Examples of chronic inflammatory diseases include chronic obstructive pulmonary disease (COPD) and systemic lupus erythematosus (SLE).

Inflammation Stages

• Inflammation has three stages: vascular and cellular responses, exudate production, and reparative phase.

• Vascular and Cellular Responses:

  • Blood Vessels: After injury or infection, blood vessels constrict briefly before dilating due to chemical mediators like histamine, kinins, and prostaglandins.
  • Hyperemia: Increased blood flow causes redness (erythema) and heat.
  • Vascular Permeability: Increased permeability leads to fluid, proteins, and white blood cells (WBCs) leaking into tissues, causing swelling (edema) and pain.
  • Pain: Edema compresses nerve endings, and inflammatory mediators irritate them.
  • Fluid Accumulation: Pulmonary edema can occur if fluid accumulates in the lungs, affecting oxygenation and carbon dioxide excretion. Joint mobility may be impaired if fluid accumulates around joints.
  • Leukocyte Margination: Slowed blood flow allows WBCs to adhere to the vessel wall, a process called margination.
  • Leukocyte Transmigration: WBCs move across the vessel wall to the injury site.
  • Leukocytosis: Bone marrow produces more WBCs and releases them into the blood, increasing the WBC count.

• Exudate Production:

  • Exudate: Fluid with high protein and WBC content that leaks into the injured area.
  • Types of Exudate:
    • Serous exudate: Clear, watery fluid containing little protein.
    • Purulent exudate: Thick, yellow-white fluid containing pus (dead WBCs, bacteria, and debris).
    • Fibrinous exudate: Thick, sticky fluid containing fibrin, which can lead to scarring.
    • Hemorrhagic exudate: Exudate containing blood, indicating significant vascular damage.

• Reparative Phase:

  • Begins shortly after the injury and continues for days, weeks, or even months depending on the severity of the injury.
  • Tissue Repair: The body attempts to restore the injured tissue to its original state.
  • Scar Formation: If the injury is severe, scar tissue may form.
  • Regeneration: Some tissues, such as skin and liver, are able to regenerate and return to their original state.

Inflammatory Exudate

• Exudate is a fluid that leaks out of blood vessels.
• Exudate is produced during the second stage of inflammation.
• Exudate contains fluid from blood vessels, cytokines, histamines, dead tissue cells, injured tissue cells, and dead phagocytic cells.
• The amount and content of exudate is determined by the tissue involved, the amount of damage, the duration of inflammation, and the intensity of the initial inflammatory process.

### Types of Exudate

• Serous exudate: clear or straw-colored, watery consistency, associated with mild inflammatory processes.
• Purulent exudate: Milky or opaque, contains leukocytes, other cells, and necrotic debris, indicates an infection.
• Hemorrhagic exudate: Red and thick, contains blood from ruptured vessels, found in injuries to capillaries due to direct damage or pressure from edema.

Inflammatory Exudate

• Exudate is a fluid that leaks out of blood vessels during the second stage of inflammation.
• The word "exudate" comes from Latin, meaning "to exude" or "to ooze."
• Exudate contains:
  • Fluid from blood vessels
  • Cytokines
  • Histamines
  • Dead tissue cells
  • Injured tissue cells
  • Dead phagocytic cells
• The amount and composition of exudate vary depending on factors such as:
  • The specific tissue involved
  • The extent of tissue damage
  • The duration of inflammation
  • The intensity of the initial inflammatory process

Reparative Phase

• The reparative phase is the final stage of the inflammatory response, where the body shifts focus from inflammation to repair.
• Chemical mediators facilitate the repair of damaged cells.
• Regeneration replaces destroyed cells with identical or similar cells, restoring tissue structure and function.
• Tissues like skin, digestive and respiratory tracts, bone, and bone marrow regenerate quickly, especially if their underlying support structures are intact.
• Tissues with limited regenerative capacity include nervous, muscular, and elastic tissues.
• Scar tissue formation occurs when regeneration is not possible.
• Fibrin assists in tissue repair by creating a network that supports the healing process.
• In the early stages of repair, granulation tissue forms, a delicate, gelatinous tissue rich in capillaries.
• As the repair progresses, granulation tissue contracts, reducing capillaries and collagen fibers, leading to the formation of scar tissue.
• Scar tissue, while essential for repair, lacks the original tissue's function and can cause complications, such as restricted heart function after a heart attack.