Burns, Scalds & Electrocution

Thermal and electrical injuries are a forensic favourite because the central question is almost always vitality — was the victim alive when the injury occurred? This note builds the medico-legal logic around antemortem vs postmortem burns, the Joule burn of electrocution, and the classic eponymous artefacts (heat haematoma, pugilistic attitude) that trip up candidates.

Definitions & basic classification

• Burn — tissue injury produced by dry heat (flame, radiant heat, hot solid, friction, lightning, electricity, certain chemicals/X-rays by convention).
• Scald — tissue injury produced by moist heat — hot liquid (water, oil, milk) or steam. By definition a scald cannot char or singe hair and rarely involves the soles/palms unless immersion.
• Electrocution — death due to passage of electric current through the body; the surface lesion is the electric mark / Joule burn.

High-yield: Dry heat → "burn"; moist heat → "scald". Scalds never singe hair and never blister beyond the area of liquid contact (no charring).

Depth-based classification

System	Grade	Layer involved	Healing
Dupuytren (6 degrees)	1st — hyperaemia / erythema	Epidermis only	No scar
	2nd — vesication (blisters)	Up to dermal papillae	No/minimal scar
	3rd — destruction of cuticle + papillae	Superficial dermis	Scar
	4th — whole skin destroyed	Full dermis	Scar + contracture
	5th — muscle penetration	Muscle	Deforming scar
	6th — charring of whole limb	Bone	—
Wilson (clinical, 3)	Epidermal / Dermoepidermal / Deep	—	—

High-yield: Dupuytren's classification of burns has 6 degrees — most commonly asked single-fact in forensic burns.

Body surface area — Rule of Nines (Wallace)

Adult: Head & neck 9 • each upper limb 9 • front of trunk 18 • back of trunk 18 • each lower limb 18 • perineum 1 = 100%.

Infant/child uses the modified rule (large head): head 18%, each lower limb 14% (Lund–Browder chart is the most accurate paediatric tool). Patient's palm with fingers ≈ 1% body surface — handy for patchy burns.

High-yield: In adults, burns involving >33–50% body surface area, or any burn at extremes of age, carry grave prognosis. Death within the first 24–48 h is usually neurogenic/primary shock; days 2–7 from secondary (hypovolaemic) shock and toxaemia; later from sepsis/septicaemia and renal failure.

Pathophysiology & cause of death

Sequence of dying in serious burns: Neurogenic shock (immediate) → hypovolaemic shock + toxaemia (first days, from plasma loss & protein breakdown products) → infection / septicaemia / acute renal failure / DIC (after a week).

• Curling's ulcer — acute duodenal stress ulcer following burns (vs Cushing's ulcer with raised intracranial pressure — a classic paired MCQ).
• Inhalation of hot gases/soot → laryngeal oedema, ARDS; carbon monoxide poisoning runs in parallel in fire deaths.

Vital reaction — antemortem vs postmortem burns

This is the single most examined concept in this topic. A body may be burnt after death to destroy evidence; the examiner must decide whether burns were inflicted on a living person.

Feature	Antemortem (vital) burn	Postmortem burn
Line of redness (hyperaemia at margin)	Present (red zone of inflammation, intravital)	Absent
Blister content	Serous fluid rich in protein + chlorides, with leucocytes; raised, inflamed base	Little fluid; air/thin serum; low protein/chloride; base not inflamed
Reparative changes	Hyperaemia, leucocyte infiltration, fibrin	None
Soot in air passages	Present (inhaled while breathing)	Absent
Carboxyhaemoglobin in blood	Raised (>10%, often much higher)	Normal/low
Enzyme / histamine at margin	Raised (histamine, serotonin, enzymes)	Not raised

High-yield: The two most reliable proofs the victim was alive in the fire are (1) soot/carbon particles in the trachea & bronchi and (2) raised carboxyhaemoglobin (COHb) in blood. A red vital line and protein/chloride-rich blister fluid support antemortem burns but are less specific.

Blister test (Hektoen / chemical): vital blister fluid resembles plasma — high protein and chloride; postmortem "blisters" are mostly air or watery fluid, poor in protein.

Stepwise forensic approach to a burnt body

1. Confirm identity (teeth, implants, DNA) — bodies are often unrecognisable.
2. Vitality → look for soot in airways, estimate COHb, examine blister fluid, search for the vital line.
3. Exclude other cause of death — was the person killed (stab, strangulation, poison) and then burnt? Internal organs are relatively protected.
4. Differentiate artefacts of heat (heat haematoma, pugilistic attitude, heat ruptures) from true antemortem injuries.
5. Manner — accident (commonest), suicide (e.g., dowry/self-immolation, kerosene), homicide.

Heat artefacts (postmortem changes mimicking trauma)

High-yield: Heat artefacts are produced after death by fire and must NOT be mistaken for antemortem injury — this distinction is heavily tested.

• Pugilistic attitude (boxer/fencer's posture): flexion of elbows, knees, hips, and clenched fists due to coagulation and contraction of muscles by heat. It is purely postmortem and gives no indication of vitality — occurs whether the person was alive or dead before the fire.
• Heat haematoma (extradural): heat causes the dura to shrink and blood (partly from sinuses, partly driven out of diploë by boiling/expansion) to collect between skull and dura. Mimics a traumatic extradural haematoma.
  • Distinguishing features of heat haematoma: chocolate/brown, friable, honeycombed (frothy) clot, often bilateral, located on the side most exposed to heat, volume usually >120 mL, with overlying charred skull; no scalp injury or fracture underlying it.
• Heat ruptures / fissures: splits in skin that look like lacerations but run along skin lines, have no bridging vessels obliterated, clean everted edges, and no vital reaction at margins.
• Heat fractures of skull: symmetrical, with a bevelled, sutural appearance; outer table flakes off.
• Postmortem steam/boiling effects: may cause apparent "blistering."

Trauma vs heat artefact	True antemortem laceration	Heat rupture
Tissue bridges	Present	Absent (along skin lines)
Vital reaction (bruising)	Present	Absent
Bleeding into wound	Present	Negligible

Electrocution & the Joule burn

When current passes through the body, the electric mark (Joule burn) forms at the point of entry where current density and resistance are highest (dry skin).

Morphology of the Joule burn:

• A raised, greyish-white/yellow area with a central depression (crater) and a surrounding rim of pale, raised, blistered skin — classically described as a collar/areola of hyperaemia.
• Skin around is firm, dry, depressed; hairs may be singed.
• Metallisation — metal from the conductor is deposited in the skin (e.g., copper → brownish; iron → rusty). Detectable by histochemistry/spectroscopy and is strong evidence of contact with that conductor.
• Nuclear streaming / polarisation of epidermal cell nuclei in the direction of current is the histological hallmark of vital electrical injury.

High-yield: The Joule burn is the entry mark of low-voltage current — central crater, raised blistered margin, metallisation, and microscopic nuclear streaming. Its presence indicates contact while alive (vital reaction).

Exit wounds are often larger, ragged, even explosive, and may be multiple; sometimes absent if the contact area is large (e.g., standing on wet floor).

Mechanism of death in electrocution

• Ventricular fibrillation — commonest with low-voltage alternating current (AC, domestic); AC at 50 Hz is the most dangerous because it traps in the vulnerable cardiac repolarisation period.
• Respiratory arrest — tetanic spasm of respiratory muscles / brainstem depression, more with high-voltage contact.
• Thermal injury / massive burns — high-voltage industrial lines.

High-yield: Alternating current (AC) is roughly 3× more dangerous than direct current (DC) at the same voltage; VF is the usual mode of death in domestic electrocution. Factors increasing danger: low resistance (wet/sweaty skin), longer contact, current path through the heart (hand-to-hand or hand-to-foot).

Lightning (atmospheric electricity)

• Voltage in millions; flashover effect often spares deep structures.
• Filigree / arborescent (Lichtenberg) burns / "lightning prints" — fern-leaf, reddish-brown branching marks; fade within hours and are not true burns (postulated to be vasodilatation/RBC extravasation).
• Magnetisation of metallic objects on the body; clothing torn/exploded; shoes split.

Feature	Domestic electrocution	Lightning
Voltage	Low (220–440 V)	Millions of volts, instantaneous
Typical lesion	Joule burn (entry/exit)	Filigree/arborescent marks (transient)
Death mechanism	VF (AC)	Massive depolarisation, respiratory arrest, cardiac arrest
Metallisation	Present	Magnetisation of metals

Clinical features & management (clinical crossover)

• Assessment: ABCDE; suspect inhalational injury (singed nasal hair, soot in mouth, hoarse voice, stridor) → early intubation before airway oedema closes the larynx.
• Fluid resuscitation — Parkland formula: 4 mL × body weight (kg) × %TBSA of Ringer lactate in first 24 h; half in first 8 h (from time of burn), remainder over next 16 h. Titrate to urine output 0.5–1 mL/kg/h.
• Carbon monoxide poisoning: give 100% oxygen (hyperbaric in severe cases); cherry-red lividity is a classic but late/unreliable sign.
• Tetanus prophylaxis, analgesia, topical silver sulfadiazine, escharotomy for circumferential full-thickness burns.
• Electrical burns look small on the surface but cause deep muscle necrosis → rhabdomyolysis, myoglobinuria → acute kidney injury, and compartment syndrome; monitor CK, give generous fluids, watch for arrhythmia.

High-yield: Parkland formula = 4 mL/kg/%TBSA Ringer lactate, half in the first 8 h. Electrical injury underestimates internal damage — beware myoglobinuric renal failure.

Complications

• Early: shock (neurogenic then hypovolaemic), airway obstruction, CO poisoning, Curling's ulcer.
• Intermediate: wound infection, septicaemia, ARDS, acute renal failure, DIC, electrolyte derangement.
• Late: contractures, Marjolin's ulcer (squamous cell carcinoma arising in an old burn scar), keloids, hypertrophic scars, psychological sequelae.

High-yield: A chronic, non-healing ulcer in a long-standing burn scar = Marjolin's ulcer (well-differentiated SCC, classically painless and lymph-node-spread is late).

Key differentials & medico-legal manner

• Antemortem vs postmortem burns — discussed above (the core differential).
• Dowry death / bride burning (India-specific): Suspect in a married woman dying of burns within 7 years of marriage with prior cruelty/dowry demand → Section 304-B IPC (dowry death) and Section 113-B Indian Evidence Act raises a presumption against the accused; Section 498-A IPC for cruelty. Such deaths are always sent for inquest by an Executive/Special Metropolitan Magistrate (not police inquest) and autopsy is mandatory.
• Accident vs suicide vs homicide: Pattern of burns, smell of kerosene, presence of accelerant, defence wounds, splash vs poured pattern, position of body, and vitality findings together establish manner.
• Scald vs splash injury in children — well-demarcated "stocking/glove" immersion scalds suggest non-accidental injury (child abuse).

High-yield: In suspected dowry death (married woman, burns, within 7 years), the inquest is conducted by a Magistrate, and postmortem is compulsory. Memorise the trio: 304-B (dowry death), 498-A (cruelty), 113-B Evidence Act (presumption).

Recently asked / exam angle

• Two single best surest signs that a person was alive during a fire → soot in air passages + raised carboxyhaemoglobin. (Repeatedly asked.)
• Pugilistic attitude is a postmortem heat artefact and does NOT indicate the person was alive — a classic trap statement.
• Heat haematoma characteristics (brown, friable, honeycombed, bilateral, >120 mL, no scalp injury) vs traumatic extradural.
• Joule burn / electric mark description and metallisation; nuclear streaming as the histological sign of vitality.
• AC more dangerous than DC; VF the commonest mode of death in domestic electrocution.
• Dupuytren's = 6 degrees; Rule of Nines / palm = 1%.
• Lichtenberg (filigree/arborescent) figures in lightning — transient, not true burns.
• Curling's ulcer (burns) vs Cushing's ulcer (raised ICP).
• Parkland formula value and timing.
• Marjolin's ulcer in chronic burn scar.

Rapid revision

1. Dry heat = burn; moist heat = scald — scalds never singe hair or char.
2. Dupuytren classified burns into 6 degrees; Wallace's Rule of Nines for adult TBSA, palm ≈ 1%.
3. Cause of death sequence: neurogenic → hypovolaemic shock/toxaemia → sepsis/renal failure.
4. Surest proof of antemortem fire death: soot in trachea/bronchi + high carboxyhaemoglobin.
5. Vital blister fluid is protein- and chloride-rich (plasma-like); postmortem is mostly air/watery.
6. Pugilistic attitude and heat haematoma are postmortem heat artefacts — no vitality value (pugilistic) / mimic trauma (haematoma).
7. Heat haematoma: brown, friable, honeycombed, often bilateral, >120 mL, no scalp/skull injury beneath.
8. Joule burn = entry electric mark: central crater + raised blistered margin + metallisation; histology shows nuclear streaming.
9. AC ~3× more dangerous than DC; domestic electrocution kills by ventricular fibrillation; wet skin and hand-to-hand path worsen it.
10. Lichtenberg/filigree figures are transient lightning marks, not true burns.
11. Curling's ulcer = burns; Cushing's ulcer = raised ICP; Marjolin's ulcer = SCC in old burn scar.
12. Dowry death (married woman, burns, within 7 yrs): magisterial inquest + compulsory autopsy; IPC 304-B/498-A, Evidence Act 113-B. Parkland = 4 mL/kg/%TBSA, half in 8 h.