Phase I: Inflammatory (Acute)
- Lasts 24-48 hours, completely over by 2 weeks
- 5 cardinal signs of :
- Redness
- Swelling
- Pain
- Heat
- Loss of function
- Initial vasoconstriction to limit blood loss with release of serotonin
- Followed by histamine release which increases permeability of capillaries, so fluid escapes
- Also released are bradykinin, other proteins and enzymes which generally increase pain so individual protects part from further injury
- White cells move in to remove debris via phagocytosis
- Minimizing the release of debris (protein, enzymes) from the damaged cells and minimizing hemorrhage decreases the size and amount of injury, even after the fact
Phase II: Proliferation or Repair (Subacute)
- Lasts 4-21 days
- Increased tissue tolerance, yet still fragile
- Synthesis, orientation, and deposition of new collagen is random
- Characterized by: muscle tightness, weakness, local edema, resolving pain (hopefully)
- Rapid proliferation of collagen with fibroblastic activity
Phase III: Remodeling (Chronic)
- Day 9- onward
- Steady increase in scar matrix
- Collagen fibers begin to align themselves with the prevailing tissue stresses
- Tissue gradually assumes the appearance & function of the “host” tissue
- Scar tissue is rarely as strong, mobile or vascular as the host
- If new tissues are immobilized for prolonged periods, new collagen becomes highly disorganized and random
No comments:
Post a Comment