electrical injuries and lightning strikes

8/10/2019 Electrical Injuries and Lightning Strikes

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Electrical Injuriesand Lightning

StrikesCOMPILATE DIN DOCUMENTATIA PUSA LA DISPOZITIE DE UK/USA


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Statistics

Patients presenting with electrical injuries have PROBLEMS thafromthe VERY TRIVIAL ->THE FATAL(in which case, they are sabeen electrocuted). If patients survive the initial exposure,

OUTLOOK is generally very good with FEW PERMANENT INJUR

ELECTRICAL BURN INJURIES account for about 3-4% OF BURNS UNIT ADMISSIONS.Electricians and linesmen are at highest risk but those working with electrical tools alssignificant proportion of this patient group.Approximately 20% OF ALL ELECTRICAL INJURIES OCCUR IN CHILDREN(with a bimodain toddlers and adolescents), usually involving cable extensions or wall outlets.For every death, there are two serious injuries and 36 reported electric shocks.Death most often occurs in young males (male:female = 9:1).Most deaths occur in the spring and summer months.Water greatly increases the risk of fatality.


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PATHOPHYSIOLOGY OF ELECTRICAL INJURY

Direct-> altering cell resting membrane potential

Conversionof electricalenergy into thermal energy massive tissue destruction and coa

Secondary damage-> falls and violent muscle contractions.

FACTORS THAT AFFECT THE DEGREE OF DAMAGE:

CurrentAC / DC (more distructive) It may result in tetanic muscular contraction, so prthe casualty from letting go of the source.

Amount of current: 1 mA = tingling sensation; >7-9 mA = muscular tetany; 20-50 mA = pbreathing difficulties -> respiratory arrest; 50-100 mA = VF; >2 A = asystole

Current path -> INFLUENCE MORTALITY (contact with both hands 60% of mortalities)

Voltage Low 70,000 V is fat

lightningdifferent story

Resistance - current travels through the body, it follows the path of least resistance

cellular level, the injury more crush, less burn

necrosis along the way

skin resistance can be affected by moisture -> may be serious deep injury with spar

clinical manifestations with different effects on different organs

potential secondary injuries from falling or being thrown to the ground


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NERVOUS SYSTEM

Acute complications: these include respiratory arrest, seizures, altered mental state, amnesia, comadysphasia. Motor deficits have also been reported.

Delayed complications: these include spinal cord injury (common) and complex regional pain syndrischaemic stroke has also been reported. Peripheral nerve injury: this may occur in the presence or tconcurrent soft-tissue injury - the prognosis is good in the latter case

RENAL SYSTEMAcute tubular necrosis, leading toacute renal failure, is common, usually secondary to myoglobinurrenal vessels and inadequate rehydration.

High-output renal failure (less common).

Transient renal changes: oliguria, albuminuria, haemoglobinuria, renal casts.

EFFECTS ON THE VASCULAR SYSTEM

Large and small vessel thrombosis may occur, resulting in surrounding tissue damage. Thrombi can a

sites from the entry point late rupture. There may also beimmediate or delayed haemorrhage at th

MUSCULOSKELETAL EFFECTS

Muscle cell disruption occurs, releasing myoglobin and creatinine phosphokinase.

Tetanic muscle contractions can result in bone fractures and dislocations as well as torn muscles.

There may be patchy swelling and necrosis with delayed development of sepsis.

Compartment syndrome can develop.

Secondary injuries arise from being thrown back from the source.


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ADDITIONAL COMPLICATIONS

Organ perforation may occur due to damage of the visceral walls and a pneumothorax ha

described, two days after a significant electrical injury.

The most common electrical injury seen in children younger than four years is the mouth bur

burns may cause facial deformities and growth problems of the teeth, jaw and face.

Cataractformation is well documented after significant electrical injury - this occurs days to

Weeks to months later -> Complex Regional Pain Syndrome may appear

Psychological sequelae: the degree is not necessarily related to the amount of physical inju

problems may last for years.

Electrical shock in pregnancyGeneral points: there is little information available about electric shocks during pregnancy and

accepted high rate of mortality may be due to publication bias. However, it is well documentefetal skin is 200 times less resistant than the skin postnatally, so less electricity may cause

significantly more harm. Indeed, an amount enough to cause minimal injury to the mother may

lethal to the fetus. Furthermore, the path of transmission becomes important here: the current pmay completely bypass the maternal heart but, if it travels through the uterus, the fetus may be

seriously injured.

Fetal harm: other than cardiac arrest, fetal complications include intrauterine growth restriction

oligohydramnios, reduction in fetal movements and spontaneous abortion.

Therapeutic electric shocks (such as defibrillation): these are safe on account of the current pa

followed which does not include the uterus.


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PRE-HOSPITAL MANAGEMENT OF ELECTRICAL INJURIES

Separate the patient from the source using a non-conducting instrument (eg rubber, wood) an

electrical supply. It is particularly important not to touch the patient before the power has bee

voltage situations, even with non-conducting material.

Commence cardiopulmonary resuscitation if required. VF is the most common arrhythmia.

Summon help - early defibrillation provides the best chance of survival.

FURTHER MANAGEMENT OF ELECTRICAL INJURY

Once in the emergency department, a full survey should be carried out including basic blood tes

note of the renal function. ECG is mandatory. Check beta-hCG and tetanus status. Pregnant wom

urgent ultrasound scan, even for apparently minor shocks.

Minor shocks: if the patient is asymptomatic and has a normal ECG, they can safely be dischareassurance. Delayed arrhythmias are exceptionally rare and are usually preceded by a preexisti

If the patient is pregnant and is well with a normal ultrasound scan of the fetus, l iaise with the obstdischarge.

Note that low voltage burns (of the type sustained from domestic electricity) are not associate

complications but the local burn is almost always full thickness. Necrosis may extend withinday

intervention with grafting tends to be favoured by burns specialists.


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MILD-TO-MODERATE SHOCKS: arrhythmias and neurological sequelae (such as apsimple observation and tend to resolve spontaneously. Offer simple analgesia for muscle p

MORE SEVERE SHOCKS:

Stabilise any life-threatening DYSRHYTHMIA.

TRANSFUSE CRYSTALLOID early: titrate volume against central venous pressure, pulse an- not by using the burns formulae.

Check BLOOD GASES (look for acidosis, may require bicarbonate), U&Es (including creConsider a clotting screen and blood typing or cross-matching in case surgery is requir

Perform ECG.

Perform cervical spine, chest and pelvic RADIOGRAPHSon any casualty who was prevunconscious as well as imaging of any injured limb.

ASSESS FOR INJURIES, system by system.

Involve SENIOR CLINICIANS.

Even if the shock was relatively minor, there may be a degree of PSYCHOLOGICAL DIS- be aware of this and offer support as required.


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CLINICAL EFFECTS

The clinical effects are very different from a high-voltage shock on account of the brief and insta

exposure and the fact that it is a direct current. The flashover effect diverts the current around th

internal injury is spared. The popular belief that lightning is invariably fatal is wrong (the mortality

30%).

Immediate effects - cardiac arrest (asystole)which may revert but which may be followed hypoxic arrest. There may be chest pains, muscle aches and neurological deficits (ranging from

transient muteness which tends to resolve within 24 hours). Contusions and tympanic rupture hav

reported.

Delayed effects - limb paralysis is commonwith flaccidity also being observed. The periphepalpable and the skin takes on a mottled blue appearance. 'Feathery' cutaneous burns (Lichten

occur immediately or over several hours but tend to heal well. Cataract formation, retinal detac

dysfunction, myoglobinuria, sensorineural deafness and vestibular dysfunction have all been rep

formation, retinal detachment, optic nerve dysfunction, myoglobinuria, sensorineural deafness adysfunction

Pregnancy - there is a high rate of fetal or neonatal death (about 50%), even where maternal su

Most lightning strikes are unwitnessed and the patient may simply present as confused - send to emergency department for assessment.


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IMMEDIATE MANAGEMENT

After the lightning has struck, the victim is safe to touch - check for responsiveness.

Commence immediate cardiopulmonary resuscitation (CPR) - this may prevent the secondar

cardiac arrest. Carry out CPR even if the casualty appears dead (pupils may be fixed and dilated as a result

muscular paresis - they do not necessarily represent brain death).

Be aware of the possibility of a spinal cord injury (evidence of head injury or tenderness or ha

of the neck or back noted if the patient is conscious).

If a group of persons is struck by lightning, direct attention to those with no signs of life, becau

others will probably recover, although burns or injuries may need treatment.

It is worth remembering that 77% of patients with cardiopulmonary sequelae die despite best resu

efforts

but, if they are to survive, it will be due to this first and immediate response.


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FURTHER MANAGEMENT

As described above, most strikes are unwitnessed. Tell-tale clues include a casualty (or multiplecoutdoors on a stormy day, exploded clothing, cutaneous burns (linear, punctate or feathery) andmembrane rupture.

Carry out full trauma assessment to look for immediate effects and initiate resuscitation as apmandatory and CT scan of the head may be indicated where consciousness deteriorates. If conscious, don't forget to document the visual acuities.

Check tetanusprophylaxis status.

Liaise with relevant departments (medical, renal, audiological medicine and ophthalmologydelayed effects.

Consider differential diagnoses, including cerebrovascular event, spinal cord injury, seizure, cStokes-Adams attack, myocardial infarction, overdose.

OUTCOME

This is generally excellent for those who survive the initial strike. The outcome is coloured by thseverity of secondary trauma. Permanent sequelae are found in 70% of cases.

Prevention The best treatment for lightning strike injuries is prevention: Remain indoors (or inside a closed

doors and windows, fireplaces and metal objects, to avoid side flashes.

When outside and unable to find shelter, maintain distance from tall trees, hilltops, or other experson caught outside in the open without cover should crouch on the ground with his or her

Do not swim in a lightning storm.

Lightning strikes through an airplane are not unusual and generally cause little or no damage


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Bibliografie Further reading & references

1. Cameron P, Jelinek G, Kelly A-M, Murray L, Brown AFT, Heyworth J. Textbook of Adult Emergency Medicinechapter

27.6: Electric shock and lightning injury, 2004. Churchill Livingstone; Postgraduate textbook

2. Hettiaratchy S, Dziewulski P; ABC of burns: pathophysiology and types of burns. BMJ 2004;328: 1427-1429.

3. Daley BJ et al; Electrical Injuries, Medscape, Jun 2008

4. Ferreiro I, Melendez J, Regalado J, et al; Factors influencing the sequelae of high tension electrical injuries.

Nov;24(7):649-53.

5. Moulton and Yates; Lecture Notes in Emergency Medicine; Blackwell Publishing (2006)

6. Fatovich DM; Delayed lethal arrhythmia after an electrical injury. Emerg Med J. 2007 Oct;24(10):743.

7. Huan-Jui Y, Chih-Yang L, Huei-Yu L, et al; Acute ischemic stroke in low-voltage electrical injury: A case repo

Int. 2010 Dec 17;1:83.

8. Ceber M, Ozturk C, Baghaki S, et al; Pneumothorax due to electrical burn injury. Emerg Med J. 2007 May;2

9. Towner E, Dowswell E, Mackereth C, Jarvis S; What works in preventing unintentional injuries in children and

an updated systematic review. NHS Health Development Agency, June 2001; Long but interesting documen

relevant information relating to this article

10. Edlich RF et al; Burns, Electrical, Medscape, Mar 2010

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