5.5: Inflammatory Response II: Inflammatory Exudate and Tissue Repair
The immune system's inflammatory response destroys the invading pathogen, permitting the tissue to heal. The changes during the cellular and vascular stages allow exudate formation at the site of inflammation. The inflammatory exudate released from the wound has high protein content and a specific gravity above 1.020.
The typical wound exudate is odorless, transparent, straw-colored, thin, and watery. Exudate, however, can differ depending on the state of wound healing. Likewise, the exudate's color, viscosity, and texture from an infected wound will vary.
The common types of exudate include serous, sanguineous, serosanguinous and purulent. Serous exudate is a transparent, amber-colored, thin, and watery plasma. It is expected during the inflammatory stage of wound healing, and smaller amounts are considered normal. Sanguineous exudate appears red, thin, and watery in deep partial or full-thickness wounds. It is also generally produced in small amounts during the inflammatory stage.
Serosanguineous exudate is thin and watery in consistency and pale red to pink in color. Next is a purulent exudate. It is a thick, opaque exudate that is brown, yellow, or green and indicates a high bacterial load and infection.
Exudate may also contain plasma proteins, including immunoglobulins, complements, and fibrinogen. Fibrinogen protein converts into fibrin, which forms the temporary wound matrix. The formation of increased tissue fluid helps remove pathogens and cell debris through lymphatic drainage.
Through tissue repair, the structure and function of damaged tissue are restored. This process depends on the injury type and the particular tissue involved. Tissue repair can happen either through regeneration or scar tissue formation.
