Burns

General Information

Classification: Integumentary

What is it?

Figure 1 Total body surface area (TBSA) Rule of 9s evaluation for adults (Source: Wikimedia Commons)

Skin injuries primarily due to excessive heat, toxic chemical agents, electricity

Causes

  • Thermal burns (~86%)
    • Dry heat (open flame, explosion)
    • Wet heat (scalding liquids, steam)
  • Electrical (~4%)
  • Chemical (~3%)
  • Others: radiation, frost bite, aerosal inhalation

Evaluation

  • Symptoms: see classification
  • Assessing total body surface area (TBSA)
    • Rule of 9s: sum affected areas to determine extent of burn (refer to Lund & Browder Chart; i.e., Figure 1)
    • Palmar method: palm represents 1% of body surface area, better for scattered burns
  • Check airways for soot, particles
  • CO, CN levels

Classification: see below

Pathophysiology: stages of zone penetration

  1. Coagulation: point of maximum damage; irreversible tissue loss or necrosis due to protein coagulation
  2. Stasis: diminished perfusion or ischemia; if not reversed (increasing perfusion) can progress to full necrosis
  3. Hyperemia: tissue perfusion increased, invariable recovery

Classification & Symptomatology

Figure 2 Superficial partial thickness burns, presenting with blister formation, erythema, and blanching (Source: OpenI, NLM)

Burns can more generally be classified into the depth-based system of superficial burns and deep burns (which can range from partial to full thickness)

There is also a degree system (1st, 2nd, 3rd degree burns referencing superficial burns, deep/superficial partial burns, and full burns, respectively), but it is less common and precise

General categorization (superficial vs deep)

Superficial burns (Figure 1)

  1. Damaged keratinocytes recruits mast cells, macrophages which secrete pro-inflammatory cytokines
    • Can stimulate nerve endings of nociceptors, causing pain
  2. Increases vascular permeability and decreased fluid retention
    • Causing interstitial edema/hypotension, blistering on surface
  3. Cytokine-mediated vasodilation also causes erythema and blanching (after palpating skin, color returns to normal)

Deep burns

  1. Can affect and damage vasculature, producing dry non-blanching surface
  2. Little to no pain (hypesthesia) since nociceptors are likely damaged
  3. Also interstitial edema/hypotension due to increased vascular permeability

Specific categorization

Superficial: limited to epidermis

Dry, erythematous

Example: sunburns (peel by day 4, heal by day 6)

Superficial partial: epidermis, upper papillary dermis

Blisters, rupturing (fluid, weeping), erythematous

Extremely painful

Example: burns due to hot surfaces/liquids/flames

Deep partial: epidermis, upper papillary, and deeper reticular dermis

Easily rupturing blisters

Pale/white surface if lose vasculature

Likely no pain

Example: due to flames/superheated gas

Full: epidermis, dermis, and extends to hypodermis

Leathery, waxy, white/charred with eschar, no blanching

No pain

Treatment

General

Replace fluids/electrolytes

Treat respiratory distress after airway analysis

Cool via water/saline solution

When to refer to burn unit? If chemical/electrical/inhalation-induced burn, burn depth (full thickness, >10% TBSA), pregnant

By burn depth

  • Superficial: OTC aloe vera, analgesics, NSAIDs for pain → little to no scarring
  • Superficial partial: debridement, topical antimicrobials, non-adherent dressing, tetanus booster → minimal scarring
  • Deep partial: fluid resuscitation, moist dressings, debridement, topical antimicrobials, grafting if necessary → higher risk of hypertrophic scarring
  • Full: requires excision and graft → require surgical treatment
    • Graft options:
      • Split thickness graft: transfer of epidermis and superficial dermis
      • Full thickness graft: transfer of entire epidermis/dermis; for small, cosmetically important regions (eyes, face, hands)

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