Open Wound: Causes

Pathogenesis (development of disease)

There are many causes of an open wound (see below). Wound healing proceeds in the following phases:

  • Exudative phase (hemostasis (hemostasis)) – in the first hours or until day 1 after injury.
    • Immigration and aggregation (clustering of individual cells into associations) of platelets (blood clots).
    • Release of cytokines (proteins that play an important role in the immune system): hemostasis.
    • Exudation (secretions) of fibrin (Latin : fibra ‘faseŕ; “glue” of blood clotting) and coagulated (clotted) blood fills the wound gap. Scab is formed, which protects the wound externally against the penetration of germs.
  • Inflammatory phase (inflammatory phase) – 1st to 3rd day after injury.
    • Catabolic autolysis: macrophages (“scavenger cells”) eliminate blood coagulum (blood clots) from the wound tissue.
    • Fibrin degradation
    • Inflammatory response and signs
    • Infection defense
  • Proliferative phase (granulation phase) – 4th to 7th day after injury.
    • Formation of granulation tissue by mediators, angioblasts, fibroblasts (connective tissue cells), myofibroblasts.
    • Regeneration of basement membrane zone and epithelium (superficial cell boundary layer).
  • Reparative phase (scar formation phase) or epithelialization phase – 8th to 12th day after injury.
    • Formation of collagen fibers
    • Wound contraction: tensile strength increases
    • Epithelialization (the wound grows with epithelial cells to).
  • Differentiation phase – from 2 to 3 weeks or up to 1 year.
    • Remodeling (remodeling processes) specific tissue: intact scar-free skinor.
    • Granulation tissue is remodeled into stress-resistant connective tissue; the wound contracts and becomes tear-resistant; a scar is formed – scars are initially well supplied with blood and appear bright red; gradually, the blood vessels are broken down and the scar appears less and less red until it finally fades.

Note: These phases are not strictly sequential, but merge into each other or sometimes run in parallel. The following forms of wound healing are distinguished:

  • Primary wound healing (sanatio per primam intentionem).
  • Secondary wound healing (sanatio per secundam intentionem)

Etiology (causes)

Mechanically caused wounds

  • Leathery wound
    • Larger areas of skin are separated from the deeper soft tissue layers by applied force (blunt force)
  • Separation wound
    • Incomplete amputation of a body part
  • Bite wound
    • Caused by bites from the animal, but also from humans.
  • Burn
    • Caused by thermal action
  • Scratch wound (superficial laceration).
  • Impalement wounds
    • Caused by the penetration of stake-like objects (vertical force).
  • Laceration
    • The skin reacts to the applied force (tangential force) by tearing apart.
  • Tear crush wound (laceration).
    • The skin reacts to the applied force (blunt force) with tear apart.
  • Cut
    • Caused by a sharp object that interrupts skin continuity (vertical or tangential force)
  • Abrasion
    • Injury to the superficial skin caused by tangential force.
  • Gunshot wound (bullet through or plug-in shot).
    • Blunt force
  • Stab wound
    • Caused by a narrow and pointed object (vertical force).

Thermal wounds – caused by exposure to heat or cold.

  • Frostbite
  • Burning

Chemical wounds

  • Due to the action of
    • Alkalis (colliquative necrosis; liquefaction of tissue, leading to deeper damage).
    • Acids (coagulation necrosis).

Actinic wounds (radiation wound; skin necrosis; radiation ulcer (radiation ulcer)).

  • Ionizing radiation: e.g., X-rays.
  • Radioactive isotopes