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Forensic pathology

Types of injuries

Electric injuries


Reviewer: Terrill L. Tops, M.D. (see Reviewers page)
Revised: 9 February 2013, last major update February 2013
Copyright: (c) 2003-2013, PathologyOutlines.com, Inc.

General
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● Two types of current cause death in U.S. and Europe: direct (rare, e.g. car battery or lightning) and alternating (most common, e.g., household items or downed power lines)

Ohm's law
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V = IR or I = V/R

● I = Current is measured in amperes
● V= Volt is a unit charge of potential energy; the difference between a point of a circuit (e.g., a live wire) relative to a reference point (e.g., ground)
● R= Resistance (ohms) of the flow of electrical energy through an organic or inorganic substance (conductor)

● If a human is in contact with a live current, then the amount of energy (volts) transmitted into the person (conductor) is inversely related to the resistance at that point of contact
● For example: decedents with moist skin are at higher risk for electrocutions than those with dry, callous skin because the latter group is more resistance to current than the former

Voltage deaths (alternating current / AC)
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Generally, low voltage is arbitrarily considered to be less than 1000 volts
● Most U.S. households have wall outlets in the 110 to 120 volt range while the home's circuit breaker consists of twice as much voltage (e.g., 220 to 240 volt range)
● Industrial work environments in the U.S. may have outlets in the high 400 volt range
● Gross findings: low-voltage electrocutions may leave little, if any injuries on the body
● Death: primarily due to cardiac arrhythmia (ventricular fibrillation)

Generally, high voltage is arbitrarily considered to be more than 1000 volts
● Power lines can range from 10,000 to over 100,000 volts
● High voltage arcs can emanate from power source and make contact with the victim who may be several feet away
● Gross findings: obvious charring on the body is common in high voltage deaths
● Death: organ damage related to thermal energy released into the body

Voltage deaths (direct current / DC)
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● Lightning is a naturally high voltage form of direct current
● Once lightning strikes a body, the lightning blast could throw the victim several feet away from the site of initial impact
● Fern-like skin lesions may develop on the body because the thermoelectric energy causes discoloration of the cutaneous blood vessels

Scene findings
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At low voltage death scenes (e.g., at family dwellings), it is important:
● Disconnect the power source to the suspected household item that may have led to the decedent's death (e.g., hair blow dryer) or remove any unusual foreign objects in contact with electrical socket (e.g., fork or knife)
● Collect any suspicious household items located near the body to be inspected systematically for faulty wiring or poor workmanship by a certified electrician
● Any electrical manufacturing defect(s) found in the product may ultimately result in a nationwide recall of that product

Gross findings
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● Full inspection of the decedent's clothing (e.g., shoes, hat, gloves, pants) may offer clues regarding the location of skin lesions
● At autopsy, especially for low voltage deaths, a careful full body (e.g., scalp, underarms, webs of the fingers/toes) inspection to find subtle skin injury

● In high voltage deaths, at autopsy, finding skin lesions are more obvious (e.g., arc/charred marks)

Histological findings
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Thermoelectric damage in high or low voltage may lead to the display of:
● Nuclear streaming or palisading of the epidermis
● Steam blisters that are present in the epidermis and/or dermis

End of Forensic pathology > Types of injuries > Electric injuries


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