electrical burns

OKWEREKWU FRANCIS .C

IntroductionEpidemiologyAetiologyPathophysiologyClinical FeaturesInvestigationsTreatmentPreventionConclusion

IntroductionBurn injuries are a world wide

problem. They rank high among injuries suffered by man.

Since its inception in 1849, commercial use of electricity has been one of the most potentially dangerous commodities in the world.

IntroductionElectrical injury includes

electrocution, electric shock, burns and secondary injuries.

The term electrical burn is used widely to describe the variety of injuries created by supraphysiologic electrical energy interacting with living tissue.

Epidemiology

According to statistical data, 0.8-1% of accidental deaths are caused by an electric injury.

Electric injury accounts for 1000 deaths each year in the United States, with a mortality rate of 3-15%

EpidemiologyApproximately 20% of all electrical injuries

occur in children, with a bimodal peak incidence highest in toddlers and adolescents.

Most electrical injuries that occur in children are at home, with extension cords (60-70%) and wall outlets (10-15%) being by far the most common sources in this age group.

Electrical burns account for 2-3% of all burns in children that require emergency room care.

EpidemiologyElectrical burns constituted 2.8% of

total burn admissions.Male: Female ratio was 1.8:144.9% of the patients were children with

age range between 22 days – 14 years.

Department of Burns, Plastic & Reconstructive Surgery, National Orthopaedic Hospital Enugu(Niger ian J Clin Pract. 2006 Dec;9(2):124-7.)

AetiologyElectrical burns are usually divided into low

voltage and high voltage injuries, the threshold being 1000volts.

a) Low voltage injuries: do not have enough energy to cause destruction to significant amt of subcutaneous tissues. The entry and the exit points, normally in the fingers and toes suffer small deep burns.

b) High voltage injuries

PathophysiologyElectrical energy causing direct tissue

damage, altering cell membrane resting potential, and eliciting muscle tetany.

Conversion of electrical energy to thermal energy, causing massive tissue destruction and coagulative necrosis.

Mechanical injury with direct trauma resulting from falls or violent muscle contraction.

PathophysiologyFactors that determine the degree of injury

include

Type of currentResistance encounteredCurrent pathwayMagnitude of energy deliveredDuration of contact.

Type of currentThe repetitive nature of AC increases

the likelihood of current delivery to the myocardium, which can precipitate ventricular fibrillation.

In contrast, DC usually causes a single violent muscle contraction, often thrusting the victim away from the source.

ResistanceIn general, tissues with high fluid and

electrolyte content conduct electricity better.

Bone is the tissue most resistant to the flow of electricity.

Nerve tissue is the least resistant, and together with blood vessels, muscles, and mucous membranes offer a path of low resistance for electricity.

ResistanceSkin is the most important factor

impeding current flow. It is the primary resistor against electrical current, and its degree of resistance is determined by its thickness and moisture.

It varies from 1000 ohms for humid thin skin to several thousand ohms for dry calloused skin.

PathwayTransthoracic currents can cause

fatal arrhythmia, direct cardiac damage, or respiratory arrest.

Transcranial currents can cause direct brain injury, seizure, respiratory arrest, and paralysis.

MagnitudeThe current intensity will also

determine the magnitude of injury. There may be individual variation on the energy dose for a specific effect.

Less energy is generally required in children, who have more water content and thin skin and, hence, better conductivity and less resistance.

Current intensity Expected clinical manifestation

1 mA Probable tingling sensation

3-5 mA "Let go" current for an average child

7-9 mA "Let go" current for an average man

16-20 mA Tetany of skeletal muscles

20-50 mA Paralysis of respiratory muscles (respiratory arrest)

50-100 mA Threshold for ventricular fibrillation

Greater than 2 A Threshold for ventricular fibrillation

15-30 A Common household circuit breakers

240 A Maximal intensity of US household current

Clinical FeaturesSkin burns/Mouth burnsUnconsciousBleedingSkeletal injuriesShockDark coloured urine/ARFRespiratory arrestTissue oedema/ Compartment syndromeNumbness/ParaesthesiaSeizures

ManagementAcute emergency, shout for help.Secure yourself.

Separate the victim from the current's source. The safest way to do so is to shut off the current e.g by throwing a circuit breaker or switch or by disconnecting the device from an electrical outlet.

Treat as multi-trauma patient with cervical immobilisation at least until the full extent of injuries has been quantified

ManagementABC’sIV accessIV fluids-Ringer’s Lactate Monitor urine output -100ml/hrARF prevention(in case of myoglobinuria)Tetanus prophylaxisAnalgesia, ulcer prophylaxis, antibioticsWound dressing

ManagementDefribillationAssociated injuries-Splint limb, referExtremities – Fasciotomies for compartment

syndromeDebridement/amputation -non-viable tissueReconstructive surgery for mouth burns

InvestigationsFBCE,U,CrECG x 24 hrsCXRABGX-ray, CTWound swab- MCS

ComplicationsSeizuresPeripheral nerve damage Psychiatric problems from depression to

aggressive behaviourCataractsParaplegia/QuadriplegiaDeformities

PreventionEducation about and respect for electricity

are essential. Ensure electrical devices are properly

designed, installed, and maintained.Electrical wiring should be installed and

serviced by properly trained personnel. Outlet guards reduce risk in homes with

infants or young children.

PREVENTION CONTD.Any electrical device that touches or may be

touched by the body should be properly grounded.

Three-pronged outlets are safest. Circuit breakers that interrupt (trip) circuits

when current as low as 5 milliamperes leaks are advisable in areas that get wet, such as kitchens and bathrooms and outdoors.

CONCLUSIONAlthough electrical burns represent only a

small proportion of burn injuries, the incidence of complications, mortality and morbidity, and disability is high. Such injuries can be prevented with proper educational programmes designed to suit the community.

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