Lightning Injuries

Michael W. Dailey, MDAssistant Professor of Emergency Medicine

Albany Medical College

Overview

• General• Lightning Myths• Severity of injuries• Triage considerations• Clinical Findings• Long term effects• Prevention

General

• 50,000 thunder storms and 8 million lightning strikes in any given day

• Lightning strikes earth more than 100 x a sec • 1000 fatalities worldwide/year• Recreational injuries are increasing but 25% of

deaths and 29% of injuries are still employment related

• High Mountain environment = 5x more lightning strikes per year

Frequency of Injury and Death

• 150 - 250 deaths/year in the U.S.• 4 - 5 times more injuries• Lightning kills more people in the US each

year than any other natural disaster– 55% more deaths than tornadoes– 41% more deaths that floods and hurricanes

combined

Incidence of Lightning Injuries

• Most in the South, Rockies, along the Atlantic Coast, and in the river valleys of the Hudson, Ohio, and Mississippi Rivers

• Occur more often in thunderstorm season - May to September

• Occur more often in afternoon and early evening

Who Gets Struck?

• In early century most common in farmers• Now, golfers, climbers, joggers and other

outdoor athletes, and construction workers• Lightning injuries tend to involve more than

one victim • 15 % of deaths occur in multiples of 2 • 15% occur in multiples of 3 or more

Lightning Production

• Warm, low pressure air moving through cool, high pressure air produces static

• The friction of moving air particles within the cloud causes ionization and complicated energy charges

Lightning Myths

1) Lightning is always fatal2) “Spontaneous Combustion and Crispy Critters” 3) Lightning never strikes in the same place twice4) Victims remain electrified5) “Suspended Animation”6) Lightning injuries are like other high voltage

injuries

Lightning Truths

• Victims do not remain electrified • Lightning is fatal 20 - 30% of the time• Lightning rarely causes deep burns - < 5%• Lightning frequently strikes the same place

multiple times - Sears Tower = > 1000/yr• No studies have shown outcomes of cardiac

arrest are different from other mechanisms

Lightning vs. High Voltage

• Much less energy imparted in lightning strikes• Therefore much less injury• The body’s electrical system may be “short-

circuited” resulting in cardiac and respiratory arrest, tinnitus, temp blindness,paralysis

• DO NOT see deep burns or myoglobinuria

Mechanism of Lightning Injury

1) Direct Strike 2) Contact - Person touching object struck3) “Splash” - lightning jumps from its

pathway and patient becomes pathway4) Ground current - current spreading radially

through the ground 5) Blunt injury

Severity of Injury

1) AC vs. DC2) Duration3) Voltage4) Amperage5) Resistance of Tissues6) Pathway

Alternating and Direct Current

• AC - electron flow changes direction on cyclic basis ( household current = 60 cycles/sec) - More dangerous

• DC - no change in flow• Lightning - oscillations are so rapid, in effect

a direct current• As DC - will cause asystole (not fibrillation)

Voltage, Amperage, and Duration

• Average voltage = 10-20 million volts • High voltage wires =15,000 volts

• Amperage = 20,000 - 100 million• Because duration is VERY short (1/10,000 -

1/1000 sec) the actual amount of energy delivered is very small– 10,000,000 V x 1/1000 sec = 10,000 W-sec– 15,000 V x 120 sec = 1,800,000 W-sec

Flash Over

• The short duration of lightning injury seldom allows energy time to break down skin and cause significant internal current flow or tissue damage

• Small amount of energy “leaks” internally, disrupting cardiovascular, pulmonary, and autonomic systems

Triage Considerations

• Major cause of death is cardio-respiratory arrest• Concentrate on those in arrest • Absence of arrest, pts are highly unlikely to die• Ventilation is key if not in arrest

Head and Neck

• > 50% of victims have at least 1 tympanic membrane ruptured

• Skull fractures and C-spine Injuries• Disruption of ossicles/mastoid• Permanent Deafness• Cataracts - corneal lesions, uveitis,

iridcyclitis, hyphema, retinal detachment

Cardiopulmonary

• Pulmonary Contusion/Hemorrhage• Numerous Dysrhythmias• Nonspecific ST changes –

rarely true evidence of infarction• Hypertension present early –

resolves in 1 - 2 hours

Cardiopulmonary Arrest

• Lightning sends heart into asystole and paralyses respiratory center in brain

• Automaticity MAY lead to the heart restarting• Respiratory paralysis lasts longer - leading to a

secondary cardiac arrest• IF THE PT IS VENTILATED - MAY AVOID

SECONDARY ARREST!!!

Extremities

• Numerous fractures and dislocations reported• Permanent paresis or paresthesias• Keraunoparalysis - blue, mottled, cold, and

pulseless extremities due to vascular spasm and sympathetic nervous system lability

- usually clears in a few hours

Skin

• Burns are usually superficial if present at alldeep burns occur in 5%

• Four types of superficial burns– Linear - from steam production and flashover– Punctate - appear as cigarette burns– Feathering - not true burns, electron showers– Thermal - from ignited cloths or metal

Other Injuries

• Neurologic – Sz, Deafness, Confusion/Amnesia, Blindness

• Concussion from shock wave• Chest pain/muscle aches• Blunt Abdominal Trauma• Intracranial Hemorrhages

Delayed Injuries

• Dysesthesias• Peripheral neuropathy• Decreased fine motor

function• Neuropsychologic

changes– memory difficulties,

depression, anxiety, insomnia,and PTSD

• From Hypoxic Cerebral Damage– Seizures and Severe

Brain Damage• From Vascular Spasm

– Spinal Artery Syndromes

Prehospital Treatment

• Triage Considerations• A,B,C,D,E - with special attention to those in

cardiac arrest (standard treatment)• Treatment of seizures is standard • Treat Hypothermia (many pts are wet)• IV access and fluids• Expeditious, safe, transport

Hospital Treatment

• ECG and Cardiac Monitoring• Labs

– CBC, Lytes, U/A, CPK with isos, appropriate X-rays/CT/MRI

• Admit for 24 hours - appropriate treatment of dysrythmias

• Those who DO NOT suffer cardiopulmonary arrest do well - those who do have a poor prognosis

Back Country Prevention

• Avoid high risk situations - BEFORE trip• Try to seek shelter - tents are poor protection

(metal poles and wet items in tent)• Avoid lone trees, ridge tops, clearings• Crouch down or kneel in forested area with

small trees• Sitting on pack may prevent step voltage

General Prevention

• If outdoors during thunderstorm, do not gather under trees

• Soccer fields, baseball diamonds and tennis courts are dangerous

• Get away from large open areas of land• Greens are a bad choice• Time for the 19th hole!