Burn Injuries

Burn Classification & Extent - Sizzling Start

• Depth:
  • 1st: Epidermis; red, pain.
  • 2nd (Partial): Dermis; blisters (superficial), mottled/less pain (deep).
  • 3rd (Full): All layers; leathery, insensate.
  • 4th: Muscle/bone.
• Extent (TBSA):
  • Rule of Nines (Adults): 📌 Multiples of 9! Head 9%, Arm 9%, Leg 18%, Trunk (Ant/Post) 18% each, Perineum 1%.
  • Lund-Browder: Accurate for children.
  • Palm Method: Palm ≈ 1% TBSA.

⭐ In children, head TBSA is larger (e.g., infant 18% vs adult 9%); Lund-Browder is key.

Burn Etiology & Patterns - Fiery Foes

• Thermal Burns:
  • Dry Heat (Flame): Deep, charring, soot, singed hairs.
  • Moist Heat (Scalds): Sharply demarcated, "tide mark", "zebra stripes"; often superficial.
  • Contact: Mirror image of hot object.
• Chemical Burns:
  • Acids: Coagulative necrosis (e.g., $H_2SO_4$ - black, $HNO_3$ - yellow).
  • Alkalis: Liquefactive necrosis, deeper penetration, soapy feel.
• Electrical Burns:
  • Entry (dry, grey-white, depressed) & Exit (everted, may be larger).
  • "Joule burn" (internal heating).
• Radiation Burns: UV, X-rays, nuclear. Delayed onset.
• Lightning: Characteristic "Arborescent" or "Filigree" (Lichtenberg) figures.

⭐ Alkali burns are generally more severe than acid burns due to deeper tissue penetration via liquefactive necrosis.

Pathophysiology & Complications - Systemic Storm

• Initial Cascade: Burn → massive release of inflammatory mediators (cytokines, histamine).
  • Causes ↑ capillary permeability → significant plasma loss, third spacing, and edema.
• Burn Shock: Primarily hypovolemic; develops rapidly.
  • Leads to ↓ cardiac output, ↓ organ perfusion. Max edema by 24-48 hrs.
• Systemic Effects:
  • SIRS (Systemic Inflammatory Response Syndrome) is common.
  • Intense hypermetabolic state: ↑BMR, catabolism, high O₂ demand.
  • Profound immunosuppression: ↑ susceptibility to infections.

⭐ Sepsis is the leading cause of death in burn patients after the initial 24-48 hours resuscitation period.

Forensic Autopsy in Burns - Charred Clues

• Key Objectives: Determine if burns antemortem/postmortem, cause of death, identity.
• Antemortem Burn Indicators (Vital Signs):
  • Soot in Airways: Trachea, bronchi; indicates breathing during fire.
  • Carboxyhemoglobin (COHb): Levels > 20-50% for significant exposure; cherry-red discoloration of tissues/blood.
  • Vital Reaction: Blisters with albuminous fluid, red line of demarcation.
• Postmortem Burn Features:
  • Absence of soot in deep airways.
  • No significant COHb elevation.
  • Blisters without inflammation, easily rubbed off.
• Other Significant Findings:
  • Pugilistic Attitude: Flexion of limbs due to heat-induced muscle coagulation (not a sign of struggle).
  • Heat Hematoma: Epidural, brick-red/chocolate-colored, honeycomb appearance (vs. traumatic hematoma).
  • Heat ruptures/splits in skin.

⭐ Modern forensic practice emphasizes multidisciplinary approach including advanced imaging (PMCT), toxicological analysis, and genetic analysis alongside soot deposition in deep airways to differentiate antemortem from postmortem burns.

• Internal Examination: Assess for visceral injuries, pre-existing diseases, toxic substances (e.g., cyanide).

High‑Yield Points - ⚡ Biggest Takeaways

• Rule of Nines (adults) & Lund-Browder chart (children) for TBSA estimation.
• Pugilistic attitude: Post-mortem heat artifact, not a sign of struggle.
• Cherry-red tissues: Indicate CO poisoning in fire victims.
• Soot in airways: Vital sign, proves victim was alive during fire.
• Heat hematoma: Post-mortem epidural artifact, not true antemortem hemorrhage.
• Scalds show clear margins, trickling; flame burns have singed hair, soot.
• Burn degrees impact prognosis; shock & sepsis are key complications.