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Thermal Injuries — Summary Based on Gautam Biswas: Review of Forensic Medicine & Toxicology

Note: The Gautam Biswas textbook is not in the library's digital collection, so this summary is drawn from comprehensive knowledge of the text (Jaypee Brothers, latest edition) cross-referenced with Robbins Pathology for pathophysiological detail.

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1. Definition & Classification

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2. Burns

Classification by Depth (Degrees)

Estimation of Burn Surface Area

• Rule of Nines (Wallace's Rule): Head & neck = 9%; each upper limb = 9%; each lower limb = 18%; anterior trunk = 18%; posterior trunk = 18%; perineum = 1%.
• Lund & Browder chart — more accurate, especially in children (accounts for age-related proportions).
• Palm method — patient's palm ≈ 1% BSA; used for scattered small burns.

Medico-legal Significance of Burns

1. Vital reaction in antemortem burns: Blisters contain protein-rich fluid (albumin >2 g%, WBCs), carbon particles in airways, soot in respiratory passages, raised COHb levels — all indicate the person was alive during the fire.
2. Post-mortem burns: Blisters contain air/serous fluid with no inflammatory cells; no soot in airway; COHb normal. Edges are brown/yellow, not red.
3. Pugilistic attitude (Boxer's attitude): Semi-flexed posture of the body seen in burned corpses due to heat coagulation and contraction of muscles — NOT a sign of defence.
4. Accidental vs. suicidal vs. homicidal burns:
   • Accidental: Most common; involvement of flame/fire, scalding, clothing fire
   • Suicidal: Extensive, involve fuel; typically involve face, neck, trunk
   • Homicidal: Rare; burns may be inflicted after death (concealment of homicide); look for injuries inconsistent with burns
5. Sati (bride burning): A medico-legal issue; kitchen/kerosene burns vs. deliberate burning
6. Flame vs. scald: Scalds produce uniform depth burns with straight edges (liquid level); flame burns are irregular.

Complications of Burns

• Immediate: Shock (hypovolaemic), respiratory failure, CO poisoning, cyanide (from synthetic material combustion)
• Early: Sepsis (Pseudomonas aeruginosa, Staphylococcus), acute kidney injury (myoglobinuria/haemoglobinuria)
• Late: Contractures, Marjolin's ulcer (SCC arising in burn scars), hypertrophic scarring, keloids

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3. Scalds

• Caused by hot liquids or steam (moist heat).
• Produce partial-thickness (2nd degree) burns.
• Pattern: "splash marks," "trickle pattern" downward flow of liquid.
• Forensic importance: Child abuse — scalds in stocking/glove distribution suggest forced immersion; splash pattern inconsistent with alleged history → suspect inflicted injury.

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4. Flash Burns

• Sudden, brief exposure to intense heat (explosion, gunpowder flash).
• Usually superficial; characteristically singe eyebrows and hair.
• Uniform distribution over exposed skin.

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5. Hyperthermia

Heat Cramps

• Painful muscle cramps due to salt depletion from sweating.
• No rise in core body temperature.
• Treatment: oral salt replenishment.

Heat Exhaustion (Heat Prostration)

• Due to salt + water depletion.
• Features: fatigue, dizziness, headache, nausea, profuse sweating, normal or slightly elevated temperature (<40°C).
• Treatment: rest in cool environment, fluid/electrolyte replacement.

Heat Stroke (Heat Hyperpyrexia)

• Most serious; core temperature >40°C (104°F).
• Classic heat stroke: elderly, chronic disease, hot environment.
• Exertional heat stroke: young, fit individuals during exercise.
• Features: anhidrosis (absence of sweating — key feature), hyperthermia, altered consciousness, tachycardia.
• Complications: DIC, rhabdomyolysis, acute renal failure, cerebral oedema.
• PM findings: Petechiae in brain, haemorrhage in GI tract, congested organs, heat-induced muscle necrosis.
• Medico-legal: Occupational hazard; deaths in locked vehicles (children); pilgrimage deaths.

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6. Hypothermia

• Core body temperature <35°C.
• Mild (35–32°C): shivering, tachycardia, confusion.
• Moderate (32–28°C): cessation of shivering, bradycardia, hypotension.
• Severe (<28°C): cardiac arrhythmias, loss of consciousness, death.

PM Findings in Hypothermia

• Pink discolouration of skin (especially face, hands, knees) — due to cutaneous vasodilatation and oxyhaemoglobin.
• Wischnewski spots (Wischnewski ulcers): Haemorrhagic erosions/ulcers in gastric mucosa — pathognomonic of hypothermia.
• Frost-bite lesions on extremities.
• Paradoxical undressing: The victim removes clothing (due to sudden vasodilation causing feeling of warmth) — can be mistaken for sexual assault.
• Terminal burrowing: Victim hides in a concealed place before death.
• Frozen bodies: pink lividity, joints rigid, no putrefaction.

Frostbite

• Frostnip: Superficial; skin pale, numb; reversible on rewarming.
• Superficial frostbite: Skin white, waxy; blisters on rewarming.
• Deep frostbite: Full thickness; black gangrene; risk of secondary infection and amputation.

Chilblains (Pernio)

• Caused by repeated cold + damp exposure (not freezing).
• Itchy, red/purple swellings on digits, ears, nose.

Trench Foot (Immersion Foot)

• Prolonged exposure to cold, wet conditions without freezing.
• Military and occupational hazard.
• Oedema, necrosis, gangrene.

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7. Key Forensic Points at a Glance

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8. Cause of Death in Fire Deaths

1. Burns (when >50–60% BSA involved)
2. Carbon monoxide poisoning (most common single cause in building fires; COHb >50% = lethal)
3. Cyanide toxicity (from burning synthetic materials)
4. Smoke inhalation and asphyxia
5. Shock (hypovolaemic or neurogenic)
6. Delayed: septicaemia, renal failure

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9. Identification of a Burned Body

• Dental records (teeth survive very high temperatures)
• Bone landmarks and skeletal anthropology
• DNA from bone marrow
• Implants, jewellery, prosthetics
• Pugilistic attitude indicates intense heat exposure, NOT a fighting stance

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Thermal Injuries — K.S. Narayan Reddy: The Essentials of Forensic Medicine & Toxicology

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1. Introduction

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2. Effects of Heat on the Body

A. Local Effects — Burns & Scalds

Definition

• Burn: Injury caused by dry heat (flame, radiant heat, hot solid objects).
• Scald: Injury caused by moist/wet heat (hot liquids, steam).

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Classification of Burns by Depth (Reddy's Degrees)

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Estimation of Body Surface Area (BSA) Burned

Wallace's Rule of Nines

In children, the head is proportionally larger (use Lund & Browder chart).

Palm Method

Prognostic Rule (Baux Score)

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Severity / Prognosis of Burns

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Types of Burns by Agent (Reddy's Classification)

1. Flame Burns — from fire/naked flame; irregular outline, variable depth
2. Scald Burns — from hot liquid/steam; uniform depth; "trickle" or "splash" pattern
3. Flash Burns — sudden explosive heat; singe hair/eyebrows; uniform superficial distribution on exposed skin
4. Contact Burns — shaped exactly like the causative object (branding iron, cigarette, hot metal)
5. Radiation Burns — sunburn (UV), X-ray burns, nuclear fallout
6. Chemical Burns — acids/alkalis (discussed separately in toxicology)
7. Electrical Burns — entry and exit wounds (covered under mechanical/electrical injuries)

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3. Medico-Legal Aspects of Burns

Antemortem vs. Postmortem Burns — Vital Reactions

Cause of Death in Fire/Burn Cases

1. Carbon monoxide (CO) poisoning — most common cause in enclosed space fires; COHb >50% = lethal
2. Burns shock — fluid loss → hypovolaemic shock (major burns >20% BSA)
3. Asphyxia — from smoke, CO₂, displacement of O₂
4. Cyanide poisoning — from burning synthetic materials (wool, nylon, polyurethane)
5. Respiratory failure — from inhalation injury, laryngeal oedema, ARDS
6. Septicaemia — delayed cause
7. Renal failure — from haemoglobinuria/myoglobinuria

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Pugilistic (Boxer's) Attitude

• Body found in a semi-flexed posture resembling a fighting stance.
• Caused by heat coagulation and shortening of muscles and tendons.
• Does NOT indicate the person was alive and fighting — purely a post-mortem heat artefact.
• Noted in 3rd and 4th degree fire victims.

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Manner of Burns — Accidental vs. Suicidal vs. Homicidal

Key point (Reddy): When a body is burned to conceal homicide, look for: injuries inconsistent with burns (fractures, ligature marks, stab/bullet wounds), low or absent COHb (person was dead before fire started), absence of soot in airways.

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Scalds — Medico-Legal Significance

• Child abuse: Scalds in a "stocking and glove" distribution (forced immersion) or with clear waterline, inconsistent with alleged history.
• Splash pattern: Accidental scalds show irregular splash droplets spreading downward.
• Forced immersion scalds: Sharp water-level demarcation; no splash; uniform depth within the zone.
• Depth is usually partial thickness (2nd degree) because water cools rapidly.

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Identification of Burned Bodies

• Teeth are most resistant to heat — used for dental comparison
• Bones — skeletal anthropology (age, sex, stature from long bones)
• DNA — from bone marrow (most heat-resistant biological material)
• Implants, prostheses, jewellery
• Fingerprints — may survive in low-temperature burns; restorative techniques available
• Personal belongings — clothing remnants, ID, watch

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4. Systemic Effects of Heat

A. Heat Cramps

• Painful muscle cramps due to excessive salt (NaCl) loss through sweating.
• Core temperature is normal.
• Seen in labourers, athletes in hot environments.
• Treatment: oral salt and water replacement.

B. Heat Exhaustion (Heat Prostration)

• Due to combined water and salt depletion.
• Temperature: normal to <40°C.
• Features: weakness, dizziness, headache, nausea, profuse sweating, pallor, rapid weak pulse.
• Not life-threatening if treated promptly.

C. Heat Stroke (Heat Hyperpyrexia) — Most Dangerous

• Classic heat stroke: Elderly, sedentary; prolonged exposure to ambient heat
• Exertional heat stroke: Young athletes/soldiers; exercise in hot/humid environment

• Petechial haemorrhages in brain, meninges
• Congestion of all organs
• Focal necrosis in liver, kidneys
• Haemorrhages in GI mucosa
• Rigor mortis sets in very quickly (due to heat coagulation of muscles)

• Deaths in locked vehicles (children, pets)
• Deaths during pilgrimage (Haj, Amarnath)
• Occupational deaths (boiler workers, miners)

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5. Effects of Cold on the Body

Systemic — Hypothermia

PM Findings in Hypothermia (Reddy emphasis)

1. Wischnewski spots — haemorrhagic erosions/submucosal haemorrhages in gastric mucosa → pathognomonic of hypothermia
2. Pink/bright red lividity — due to cutaneous vasodilation; COHb needs to be excluded
3. Pink discolouration of skin — especially cheeks, knees, hands
4. Frost bite changes on extremities
5. Pancreatitis — occasionally noted
6. Cold diuresis — kidneys concentrating function affected; bladder may be full

Forensic Peculiarities

• Paradoxical undressing: Victim removes clothing shortly before death due to sudden peripheral vasodilation causing a feeling of warmth — may mimic sexual assault scene.
• Terminal burrowing: Victim crawls into a confined space (under a bed, in a cupboard) — due to primitive burrowing reflex; found in isolated hypothermia deaths.
• Pink body in a cold environment + full bladder + Wischnewski spots = hypothermia until proven otherwise.

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Local Effects of Cold

Chilblains (Erythema Pernio)

• Repeated exposure to cold + damp (not freezing).
• Purple-red, itchy, swollen lesions on fingers, toes, ears, nose.
• Reversible; not dangerous.

Trench Foot (Immersion Foot)

• Prolonged exposure to cold + wet environment without freezing.
• Seen in soldiers, flood victims.
• Oedema → blistering → gangrene if untreated.

Frostbite

• Actual freezing of tissue — intracellular ice crystal formation causes cell death.

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6. Summary — Key Forensic Points (Reddy)

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