Paper I
Question
Factors affecting wound healing
Answer
Local factors
- Infection: The single most important cause of delayed wound healing — bacterial contamination prolongs the inflammatory phase and causes further tissue damage
- Mechanical factors: Movement/tension at the wound site, early mobilization, can disrupt the healing wound
- Foreign bodies: Impede healing and act as a nidus for continued inflammation/infection (e.g., sutures, glass, dirt fragments)
- Size, location, and type of wound: Large wounds, wounds in poorly vascularized areas, and wounds with extensive tissue loss heal more slowly
- Blood supply: Poor local vascularity (e.g., peripheral vascular disease) impairs delivery of oxygen/nutrients
Systemic factors
- Nutrition: Protein deficiency impairs collagen synthesis; vitamin C deficiency impairs collagen cross-linking (scurvy); zinc deficiency impairs epithelialization
- Metabolic status: Diabetes mellitus impairs healing through multiple mechanisms (microvascular disease, impaired neutrophil function, neuropathy)
- Circulatory status: Inadequate blood supply from atherosclerosis, venous insufficiency
- Hormones: Glucocorticoids impair healing (anti-inflammatory effect, inhibit collagen synthesis)
- Age: Wound healing is generally slower in the elderly
- Immune status: Immunosuppression (e.g., HIV, chemotherapy) impairs the inflammatory and repair response