Injury due to Heat, Cold and Electricity

Injury due to Heat, Cold, and Electricity

Overview of Physical Injuries

  • Definition: Physical injuries categorized into types based on the agent causing them.

  • Physical Agents:

    • Heat

    • Cold

    • Electricity

    • Irradiation

Injury Due to Heat

Factors Determining Heat Injury

  • Damage to cells is influenced by:

    • Length of exposure time to high temperatures.

    • Temperature level.

    • Minimal temperature causing damage is 44°C/6 hours.

  • Types of Heat Sources:

    • Dry source: Resulting from burning (combustion).

    • Wet source: Such as hot liquids or steam leading to scalds.

Classification of Heat Injury

  • Severity: Based on the depth of skin and tissue injury.

  • Extent: Area of the skin that is burned.

Degree of Severity of Heat Injuries

I. Degree (Stadium Erytematosum)

  • Causes slight temperature increase (long exposure) or high temperature (short exposure).

  • Symptoms:

    • Redness and tension in the skin.

    • Pain and sensitivity.

  • Healing: Typically without trace.

II. Degree (Stadium Vesiculosum et Bulosum)

  • Characterized by blister formation; destruction of the epidermis (necrosis).

  • Possible involvement of the superficial corium (deep II. degree).

  • Healing: Generally occurs without trace, except for deep cases.

III. Degree (Stadium Escharoticum seu Necroticum)

  • Full thickness injury involving epidermis, corium, and sometimes underlying tissues.

  • Necrosis present.

  • Healing: Requires skin transplantation and results in scarring.

IV. Degree (Carbonisatio)

  • Complete tissue destruction including muscles and bones.

  • Likely due to fire exposure.

  • Outcomes may vary from partial to total body involvement, with full body exposure leading to post-mortem situations.

Adult Surface Burn Classification

  • Rule of Nines: Estimates body surface area affected by burns in adults; different schemas exist for children.

  • Prognosis poor if burned area exceeds 50%.

  • Note: Clothing can offer some protection until ignited.

Scald Injuries

  • Charring may occur (for example, molten metal exposure).

  • Types of Scalding Patterns:

    • Immersion exhibits a fluid level mark.

    • Splashing results in scattered punctate areas.

    • Runs and dribbles leave distinct patterns.

  • Context of Incidents: Industrial and household accidents, including child abuse scenarios.

Examination of Bodies from Fire Incidents

  • Forensic Pathology Investigation should address:

    • Identification of the deceased.

    • Determining if the victim was alive when the fire initiated.

    • Cause of death analysis.

Indicators of Life During Fire Exposure

  • Presence of a cherry pink area of preserved skin.

  • Soot particles found in respiratory tracts indicate inhalation of smoke.

  • Body's position as a significant factor in the investigation.

Effects of Inhalation During Fire

  • Inhalation leads to:

    • Soot in airways.

    • Development of carboxyhaemoglobin in the bloodstream.

  • Absence of indicators in rapid flash fires like gasoline or aircraft incidents.

Causes of Death in Burns and Scalds

Rapid Deaths

  • Asphyxiation from heat in airways.

  • Toxic effects from inhaled gases (e.g., carbon monoxide, cyanide).

  • Tissue destruction leads to toxic release.

  • Pain-induced shock.

Delayed Deaths

  • Conditions such as:

    • Hypovolemia.

    • Infection leading to sepsis.

    • Stress ulcers (Curling’s ulcers).

    • Acute tubular necrosis resulting in renal failure.

    • Adult respiratory distress syndrome (ARDS).

Injuries on Burned Bodies

  • Common artifacts:

    • Splits of the skin due to brittleness.

    • Heat hematoma: Clotted blood collection rupturing venous sinuses, producing brown and spongy structures.

Cold Injury (Hypothermia)

  • Vulnerable groups:

    • Elderly individuals due to living conditions.

    • Inebriated individuals from vasodilation effects.

    • Children with high body surface-to-weight ratios, losing heat rapidly.

  • Local effects include frostbite, leading to peripheral digit necrosis requiring surgery.

Signs of Hypothermia

  • Definition: Drop in core temperature exceeding a few degrees.

  • Body's response to generate heat includes:

    • Blood flow diversion from the skin.

    • Shivering as a thermoregulatory mechanism.

  • Critical Temperatures:

    • Below 32°C: Cessation of shivering.

    • Death plausible between 26 - 30°C.

Classification of Hypothermia

  • Mild: 35-32°C.

  • Moderate: 32-30°C.

  • Severe: <30°C.

Autopsy Findings in Hypothermia Victims

  • Areas of skin showing pink or brown with blurred margins, especially around joints.

  • Presence of stress ulcers in stomach due to hypothermic stress.

  • Organ infarction, particularly in pancreatitis cases.

Electrical Injury

Overview

  • Definition: Effect of electric current passage through the body (ictus electricus, electrocutio).

  • Common in both industrial and household accidents.

Electric Current Characteristics

  • Factors:

    • Electron flow (100 mA can be fatal).

    • Voltage levels typically range from 110 – 240 V.

    • Types: Alternating Current (AC) versus Direct Current (DC).

    • Tissue resistance influences damage severity, with dry skin providing higher resistance.

Mechanism of Injury

  • Entry and Exit Points:

    • Commonly entry through hands, exit via feet or the other hand, creating a path across the thorax.

  • Effects:

    • Instantaneous shock leading to cardiac arrest and respiratory issues.

    • "Hold on" Effect: Muscle spasm preventing release from the conductor.

Modes of Death from Electrical Injury

  • Common Outcomes:

    • Ventricular fibrillation is the primary cause.

    • Peripheral respiratory paralysis is typical.

    • Rare instances of brainstem paralysis occurring with entry points in the head.

Electrical Injuries and Lesions

  • Examination must include scene evaluation and autopsy for electrical marks (signum electricum).

  • Burn injuries may appear crater-like resembling II. to IV. degree burns.

Death from Lightning

  • Definition: Effects of atmospheric lightning or thunderbolt (fulguratio, ugar groma).

  • Occurrence is climate-dependent, more common in tropical zones.

  • Massive electrical forces involving millions of amperes and significant voltages can cause:

    • Burns

    • Fractures

    • Lacerations

    • Unique skin patterns resembling ferns or branches.