Burn Pathophysiology and Classification

Burn Pathophysiology

• Burn injuries trigger an inflammatory response in the skin and other integumentary structures.
• Causes include excessive heat, radiation, caustic chemicals, and electricity.
• Heat causes protein denaturation and irreversible cellular damage.
• All burns result in an acute inflammatory response.
• Burn severity correlates with exposure type and duration of exposure to the affected surface area.

Burn Classification

• Superficial partial-thickness (first degree): Damages only the epidermis, characterized by redness, warmth, pain, swelling, and loss of function. Capillary permeability increases, but there is no cell death or scarring, and healing is uneventful. Epithelial cells regenerate rapidly.

• Deep partial-thickness (second degree): Damages the epidermis and part of the dermis. Blisters form due to fluid accumulation, as the epidermis and dermis separate. Significant loss of function occurs. Healing often leads to scarring and fibrosis.

• Full thickness (third degree): Damages the entire epidermis, dermis, and subcutaneous tissue. Skin appears gray, white, cherry red, or blackened. Nerve endings are destroyed, making it not painful. Healing is difficult due to extensive tissue loss, and skin grafting is usually necessary. Extensive scarring and the formation of eschar (dead tissue) is common. Loss of elasticity leads to contractures.

Burn Pathophysiology: Complications

• Loss of skin function: Severe burns can lead to body fluid shifts, impaired blood circulation, edema (swelling), dehydration, electrolyte imbalance, renal shutdown, circulatory shock, and microorganism invasion.
• Overwhelming metabolic demand: Increased metabolic demands, risk of malnutrition, and temperature regulation problems.
• Significant Hemodynamic Changes
  • Poor perfusion (inadequate blood flow) is problematic for vital organs, requiring constant oxygen flow.
  • Edema (swelling) increases interstitial fluid volume while reducing the vascular volume, increasing peripheral resistance, and decreasing cardiac output.
  • Hematocrit and blood viscosity increases as vascular fluid is redistributed into the interstitial space.

Burn Clinical Manifestations

• Clinical manifestations vary by burn depth.
  • Superficial partial-thickness burns: Erythema (redness), warmth, pain, and swelling.
  • Deep partial-thickness burns: Blisters, erythema, pain, edema, and serous exudate.
  • Full-thickness burns: Erythema, eschar, edema, exudate and the destruction of nerve endings, sweat glands, and hair follicles.

Burn Diagnosis

• Wound depth is classified according to the affected tissue layers.
• The rule of nines is used to estimate the extent of burn injury, assessing percentages of the body surface area affected by different categories of burns.

Burn Treatment

• Minor and moderate burns: Removing the source of the injury, stopping the burning process, cleansing (chemical burns with copious water, minor burns with tepid water), and applying an antimicrobial ointment, dressing, and frequently changing the dressing to remove debris and necrotic tissue.
• Moderate and major burns: Emergency medical admission; focusing on stabilizing airways, breathing, and circulation; fluids (to restore water and sodium balance); nutrition (to meet increased metabolic demands); antibiotics; and analgesics (to manage pain).
• Major burn treatment includes:
  • Wound management (sterile saline cleansing, removing necrotic tissue).
  • Preventing infection (e.g., hydrotherapy to cleanse wounds, removing dead tissue, skin grafting).
  • Long-term rehabilitation (to manage scarring, contractures, deformity, chronic pain and depression).

Explore the intricacies of burn injuries, including their pathophysiology and classification. This quiz covers the inflammatory response triggered by burns, the types of burns based on severity, and the healing processes involved. Understand how factors like heat and chemical exposure impact burn severity.