Transcript Lightning Injuries

Lightning Injuries
Wilderness Medical Consortium
Matthew Sholl, MD, MPH
Ted Curcio, MD, FAECP
Introduction
In its power, instantaneousness, and beauty,
lighting has always inspired humans
Lighting becomes a challenge for wilderness
medical practitioners who must overcome the
myths and superstitions of lightning and
practice medicine based on the little science
surrounding lightning
Outline
Lighting superstitions
Lightning’s place in history
Myths surrounding lightning
Lightning truths
Epidemiology of lightning injuries
Physics of lightning
Superstitions and Myths
Superstitions and Religion
Akkadians - 2200 BC - Semitic people living on Arabic
peninsula
Depicted a goddess holding sheaves of lighting bolts in each
hand and a weather of driving a chariot with lightning bolts
created by his whip
Greeks - 700 BC - Zeus - god of thunder - received his
thunderbolt weapons from Cyclops. Used to assume
celestial sovereignty
Lightning invented by Minevera, goddess of wisdom
Romans - Jupiter - used lighting as a tool of vengeance
Roman emperors often wore laurel wreaths or sealskin to
ward off lightning
From the website: http://www.neiu.edu/~lojajou/myIndividual/Ackadian.htm, accessed on 2/8/06
From the website:http://www.islandnet.com/~see/weather/almanac/arc2002/alm02aug2.htm
Superstitions and Religion,
cont.
Vikings - Thor the Thunderer
Pulled through the heavens on his golden chariot pulled by
two goats tossing lighting down at his enemies
Buddha - statues depict Buddha carrying lightning
Tien Mu - Chinesse goddess of lighting
Africa - Basuto tribe - lighting depicted as the great
thunderbird, Umpundulo,
Navajo - story of the hero Twins who used “lightning
that strikes straight” and “lightning that strikes
crooked” to kill mythological beasts that plagued the
Navajo people and in turn created the Grand Canyon
Myths Regarding Lightning # 1
Lightning Strikes are Always Fatal
Lay persons and media drawn to more severe cases and
over estimate mortality
Case reports suggest a mortality between 5 - 30% and
morbidity of 70%
Major Cause of Deaths is Burns
Only a small percentage of patients ever sustain deep
burns, no “crispy critters”
Only cause of immediate death is cardiac arrest
Lightning Victims Remain Electrified
Has unfortunately lead to delayed resuscitation of victims
Gatewood, “Lightning Injuries”, Emerg Med Clin N Am 22 (2004)
Myths Regarding Lightning # 2
Lightning Never Hits the Same Place Twice
Certain objects or locations are predisposed to lightning
strike
If those conditions recur, lightning will likely strike again
Risk of Lightning Strike Exists Only When Clouds
Overhead
In reality, lightning may strike up to 10 miles ahead of a
storm
It is the times before and after a storm, when clouds are
likely to not be present, that are most dangerous for
lightning strike - due to positive lighting which strikes away
from the rain core
Myths Regarding Lightning # 3
Wearing Rubber Soled Shoes Is
Protective
Air is an excellent insulator, and if lightning can
overcome the insulative properties of air it can do
so with rubber soles
Rubber Tires on a Car are Protective
The metal cage, not the tires, are protective on a
car, similar to the Faraday cage
Occupying a Building is Protective
Significant number of injuries occur inside
buildings. Plumbing fixtures, phone lines and
outside appliances allow for side flashes.
Hard wired phones are not grounded and act
as a conduit for electrical current
Myths Regarding Lightning #4
Wearing Metal Attracts Lighting
No evidence to suggest that wearing metal that does not
significantly increase a person’s height will predispose to
lightning strike
Lighting Always Hits the Highest Object
Lightning only “sees” objects within 30 - 50 meters from its tip.
Multiple documentations of lighting striking halfway down flag
poles, in mountain valleys, etc.
Lightning can Occur Without Thunder
Whenever there is lightning there is thunder and vice versa
There is no Danger From Lighting Unless it is
Raining
10% of lightning strikes occur in no rain due to the distances
The Truth About Lightning
Electricity vs. Lighting
While the gross electricity dispersed by lightning is
enormous, the net energy delivered to the patient is
much less due to the brief duration of exposure,
resistance, and flashover
From - Gatewood, “Lightning Injuries”, Emerg Med Clin N Am 22 (2004)
Epidemiology of Lightning
Epidemiology of Lightning
Strikes
Real-time lightning detection networks in the US
allow for precise numbers strikes
20 million cloud-ground strikes/year
Up to 50,000 flashes/hour in summer afternoons
NOAA and NOAA’s National Climatic Data
Center (NCDC) records and complies data from
each National Weather Service station
1959 - 1994 Storm Data reported 3529 deaths, 9818
injuries and 19814 properties damaged from lightning

BUT, Storm Data relies on lay person’s reports and news
reports and may underestimate
Injuries and Deaths
Average of 200 deaths/year reported
between 1940 - 1974
100 deaths/year over a 17 year study ending
in 1986
Currently estimated that lighting causes 50 300 deaths/year in the US
4 - 5 x as many injuries suspected
Second only to floods and flash floods as the
leading cause of weather related deaths
Where Do Strikes Occur??
Central Florida has highest number of
strikes/year - Figure #1 + 2
12 strikes per km2/year
Flash density decreases to the north and
west from FL
Populous eastern cities account for many of
the other casualties - Figure #3
Maximum rate of lighting casualties is in the
Rocky Mountain and Plain states
New Mexico and Wyoming have highest
population controlled casualty rates
FL, CO, NC top for both casualty and casualty rate
From - Gatewood, “Lightning Injuries”, Emerg Med Clin N Am 22 (2004)
When Do Lightning Injuries
Occur?
Occurrence depends highly on time of
year and time of day
Two thirds of lighting flashes occur over
the summer months of June, July August Figure 4
More than half of all strikes occur in the
afternoon between the hours of 1500 1800 - Figure 5

0000 - 0600 account for nominal number
From - Gatewood, “Lightning Injuries”, Emerg Med Clin N Am 22 (2004)
From - Gatewood, “Lightning Injuries”, Emerg Med Clin N Am 22 (2004)
Final Epidemiology
The odds of becoming a lightning victim in the U.S. in
any one year is 1 in 700,000
The odds of being struck in your lifetime is 1 in 3,000
84% of victims over 34 years in the Storm Data study
were men and 91% of the time there was one victim
Cooper, “Lighting Injures”, Wilderness Medicine, Auerbach 2001, and the website,
http://news.nationalgeographic.com/news/2004/06/0623_040623_lightningfacts.html, accessed on 2-7-6
Lightning Physics
Lightning Production
The Sequence of a Strike
Lightning begins as a weak and
slow leader stroke from the cloud
Breaks down the air and ionizes a
path of superheated ions, creating a
low resistance plasma column
The leader “steps” at 50 meters,
retreats then descends back 50
meters further
This occurs until 60 - 50 meters
from the ground
Lightning only “sees” objects
within30 - 50 meters of its tip
Objects nearest the tip emit upward
streamers due to the induced
charge at tier tip
Attachment and return strokes
Ground to cloud - represents the
visible lightning
From the Website:
http://wvlightning.com/cgdesc.shtml, accessed on 28-06
Multiple Return Strokes
The sequence below demonstrates the
multiple return stroke process of a cloudto-ground lightning strike:
Stage 1: Storm electification results in
pockets of charge in the cloud. For the
sake of illustration, polarity has been
ignored here
Stage 2: Main Charge Pocket discharges
to ground via stepped leader connection.
Dendritic network of branches 'taps'
charge in main charge pocket.
Stage 3. Established lightning channel
brings 'earth ground' close to Charge
Pocket #3.
Stage 4. Charge Pocket #3 discharges to
the established channel. Earth ground is
now brought deeper into the cloud.
Stage 5. Charge Pockets #2 and #4 now
are close enough to 'earth ground' via the
conductive lightning channel that they too
can discharge to ground.
From the Website:
http://wvlightning.com/rsdesc.shtml#animaccessed
on 2-8-06
Same Sequence in Full Speed
From the Website: http://wvlightning.com/rsdesc.shtml#animaccessed on 2-8-06
Types of Lightning - Sheet
Lightning
Sheet Lighting
Because of the separation of
opposite charges, static electricity
exists and a spark or lightning flash
appears between the top and
bottom of the cloud

Lighting occurring within the cloud
This type of lightning is called sheet
lightning because it is hidden from
view and is seen as a flickering of
light within the cloud.
From the website:
http://whyfiles.larc.nasa.gov/text/kids/Problem_Board/problems/electricity/static2.html,
accessed on 2-7-06
Types of Lightning - Ribbon
Lightning
Ribbon Lightning:
Formed when strong winds spread out
the plasma channel of a lightning strike.
From the website: http://www.museum.vic.gov.au/scidiscovery/lightning/shapes.asp, accessed on 2-7-06
Types of Lightning - Bead
Lightning
Bead Lighting:
Bead lightning does not disappear all at once
Small 'beads' of lightning remain for a short while
after the rest of the lightning strike disappears
Some think that bead lightning occurs when a
lightning strike is seen edge on
From the website: http://www.museum.vic.gov.au/scidiscovery/lightning/shapes.asp, accessed on 2-7-06
Types of Lightning - Ball
Lightning
Ball Lightning:
True nature of ball lightning unknown
Some postulate that it is a ball of plasma that is
somehow trapped by strong magnetic fields
Normally appears as a freely floating glowing ball, about
the size of a grapefruit
Sometimes the ball is seen to pass through walls or
ceilings
From the website: http://www.museum.vic.gov.au/scidiscovery/lightning/shapes.asp, accessed on 2-7-06
A Word on Thunder…
Caused by explosive shockwaves resulting
from instantaneous heating of ionized air
along the path of lighting stroke
Controversy exists regarding the temperature of
lightning (varies based on diameter of the strike) but
estimated at 8000° C (14,432 ° F) to 50,000 ° C
(90,32 ° F)
Thunder rarely heard when strike is > 10
miles away
Time between strike and thunder can roughly
estimate the distance to the strike
Distance to the flash in miles = # of seconds
between lighting and thunder divided by 5
Many conditions reduce audibility of thunder
Mechanism of Injury
Lightning’s Mechanism of
Injury
Lighting injures humans by three general
mechanisms:
1.
2.
3.
Electrical effects- through direct injuries
Heat
Concussive forces
May also directly cause a house or forest
fire
Causes 75,000 forest fires/year and responsible
for 40% of all forms of fire
Direct Injuries from Lighting
Direct Strike - most likely to injure those in open pace, unable to
find adequate shelter
Splash injuries - lightning first comes into contact with a solid
object then “splashes” into a victim in close proximity
Current seeks the path of least resistance and may jump from
object to person or person to person
Contact injury - occurs when a victim is in direct contact with an
object struck
Step Voltage (ground current - stride voltage) - current of ground
strike travels outward radially (like a pebble in water)
Humans offer less resistance than ground (being primarily
composed of salt water) and potential difference exists between
even a normal human stride
Blunt Trauma - occurs as consequence of proximity to
lightning’s concussive wave, may throw patient 10 yards,
rupture TM’s, etc.
Why Do Livestock Die in
Lightning Strikes?
From the Website: http://www.lightningsafety.noaa.gov/outdoors.htm, accessed 2-7-06
Pathophysiology of
Lightning Injury
Unidirectional massive current
Differentiated from direct or alternating
current

But behaves like DC current causing asystole
Joule’s Law =
(Energy = Current2 x Resistance x Time)

As resistance goes up, so does heat generated by
passage of the current
Flashover
Skin will breakdown within a finite amount of time
when exposed to electricity or heat
Generally, lightning’s duration of exposure is brief
enough that skin does not break down
A large portion of the energy travels along the skin
and outside of the body
A portion of energy does enter the cranial orifices
including the ears, eyes, nose, throat, etc.
Entry into cranial orifices leads to direct contact with
the brainstem including the floor of the fourth ventricle
and cardiorespiratory control centers
From here, energy travels through CSF to vessels and
heart
Injury Patterns in Lighting
Strike
Cardiopulmonary Arrest
Neurologic Injuries
CNS Injury
Peripheral Nerve Injury
Autonomic Dystrophy
Post-Traumatic
Headache
Burns
Blunt and Explosive
Injuries
Eye Injuries
Ear Injuries
Hematological
Abnormalities
Fetal Survival
Psychological
Consequences
Cardiopulmonary Arrest
Most common cause of death is
cardiopulmonary arrest
Death highly unlikely (P<0.0001) unless arrest occurs
Primary and Secondary arrest patterns:
Primary Arrest - injury first occurs due to lightning’s
effect on brainstem causing cardiac and pulmonary
standstill
Due to automaticity of the heart, organized contraction
will restart within brief time
Respiratory arrest caused by paralysis of the medullary
center lasts longer
Resultant hypoxia may induce arrhythmia and
secondary cardiac arrest
Triage Considerations
Primary and Secondary arrest
phenomenon have major implications
on the triage of lightning strike victims
If you are on scene or in immediate
proximity to victims of a lightning strike,
focus efforts on those in arrest
Those in arrest may be carried through
hypoxic period and thus saved
Other Cardiopulmonary
Injuries
ECG changes consistent with ischemia and damage
are common
ECG changes may be delayed up to one week
Most changes will resolve within days
CK and MB’s may be elevated
Troponin not studied or well understood
Autopsy studies suggest focal areas on myonecrosis
Many see interval changes (QT prolongation)
Pulmonary edema, pulmonary contusion,
hemoptysis, or hemorrhage caused by blunt or
concussive injury has been reported
Neurologic Injuries
Cause the greatest number of long term
problems or survivors
May see damage to central, peripheral
and sympathetic nervous systems
Anatomic studies (CT/MRI) often
negative while functional studies
(SPECT/PET) are often positive
Central Nervous System
Energy traveling through the brain may lead
to coagulation of brain substance, CNS
bleeds (hematomas, subarachnoid bleed)
Blunt injuries are also possible from
concussive or explosive forces
Seizures possible due to hypoxia or injury
Anterograde amnesia almost universal
Lasts for hours to days
Retrograde amnesia less common
Common CNS Injuries
Sleep disturbances
Endocrine dysfunction
Persistent paresis
Paresthesias
Incoordination
Delayed and acute
cerebellar ataxia
Hemiplegia
Aphasia
Centrally derived pain
Cerebellar dysfunction
and atrophy
Atrophic spinal paralysis
Altered psychomotor
function
PTSD/Storm Phobia
Mood Abnormalities
Dysesthesias
Headaches
Emotional liability
Libido alterations
Decreased exercise
tolerance
Parkinsonism
Peripheral CNS Injuries
Pain and paresthesias are common along injury path
May be delayed days to weeks
In severely injured patients, 2/3 develop
keraunoparalysis (lower extremity paralysis) and 1/3
develop symptoms in the upper extremity
Extremities appear cold, clammy, mottled, insensate and
pulseless
Due to sympathetic instability and intense vascular spasm
 Similar to Raynaud’s phenomenon
Usually resolves in hours (fasciotomy almost never
necessary)
Autonomic Dystrophy
Victim may exhibit multiple sympathetic
alterations such as:
Pain syndromes
Altered temperature
control
Perfusion alterations
Altered skin
appearance
Altered skin
reactions
Reflex autonomic
dystrophy
Posttraumatic Headaches
Most lightning victims suffer from severe
unrelenting headaches for months out
from the injury
Frequently associated with vomiting
Tinnitus and dizziness/vertigo common
Burns
Flashover prevents victims from
incurring anything but minor burns
Five categories of burns
1.
2.
3.
4.
5.
Linear Burns
Punctate Burns
Feathering
Thermal Burns
Combinations
Linear Burns
1 - 4cm wide and follow areas of heavy sweat
concentrations
Beneath breasts, down mid-chest, and in mid
axillary line
Usually first and second degree burns
Develop within hours of the strike
Most likely steam burns as patient’s sweat or
rainwater evaporates during flashover
Punctate Burns
Multiple, clearly spaced, discrete circular
burns
Appear as small cigarette burns
Range in size from millimeters to
centemeters
Feathering
AKA - ferning, Lichtenberg’s Flowers,
keraunographic markings, and arboescent
burns
Pathologic of lightning injuries
Transient arborescent markings on the skin
that follow neither vascular or nerve pathways
Pink to brownish and lightly palpable
Not true burns
Thought to represent RBC’s extravasated into the
superficial layers of the skin from capillaries due to
dielectric breakdown of the skin and massive
electron shower
Thermal Burns
Occur if the victim’s clothing is ignited or if the
victim is wearing metal
Metal objects become superheated and cause 2nd
or 3rd degree burns
Blunt and Explosive Injuries
Blunt injuries occur due to both the
explosive force of lightning as well as
victims being thrown or supercharged
objects hitting the patient
Any pattern of injury possible
Myoglobinuric renal failure never
reported
Eye Injuries
Due to intense light, direct thermal injury,
electrical damage, or the shock wave
More than 50% of patient incur ocular injury
Cataracts commonly develop within the first days
after the injury but may develop as late as 2 years
out

Frequently bilateral
Dilated or uncreative pupils can not be used
as a prognostic sign in brain injury or criterion
for brain death as these phenomenon
common in lightning victims
Other Eye Injuries
More Common
Corneal Lesions
Hyphema
Uveitis
Iridocyclitis
Vitreous hemorrhage
Less Common
Choroidal rupture
Chorioretinitis
Retinal detatchment
Macular degeneration
Optic atrophy
Diploplia
Loss of color sense
Photophobia
Mydriasis
Horner’s Syndrome
Anisocoria
Loss of light relfexes
Ear Injuries
Temporary deafness is common
Due to intense noise and shock wave
Approximately 50% of victims have
rupture of one or both TM’s
Ossicle disruption, permanent deafness,
facial palsies, vertigo, tinnitus, and
ataxia also reported
Other Injuries
Fetal Injuries
Unpredictable survival if pregnant woman struck

Of 11 reports, 5 survived (w/out Abnlity), 3 resulted in live
births with subsequent death, remainder with still born
Hematologic
DIC, + Coomb’s Test, etc.
Psychological Dysfunction
Neurocognitive deficits, depression, loss of short
term memory, PTSD, behavioral changes, fatigue,
sleep disturbances
Depression almost universal
May not be ale to return to work
http://www.lightning-strike.org/
Treatment
Initial First Aid and Triage
First priority = SAFETY
Remember, factors that lead to the original
lightning strike still exist
Follow common wilderness protocols
Scene Safety, Airway, Breathing, Circulation,
Disability, Environment

Remember, many strikes occur with rainfall. Beware of
cold injuries
Lightning strike victims deserve a thorough
evaluation
Treatment of seizures is standard
Expeditious transport
Triage Considerations
IF the rescuer is on scene or immediately
close, triage priorities are reversed
Those in arrest are preferentially treated first as
supportive care with rescue breathing may abort
the secondary arrest
This being said, if the patient does not regain
pulse and respirations within a short period of
time, they will likely die
Be wary not to mistake hypothermia for death!!

Rule of thumb is 20 - 30 minutes of CPR
Hospital Treatment
No standard recommendation for hospital
observation/admission for monitoring of
mental status and cardiovascular stability
Most admit for 24 hours - appropriate treatment of
dysrythmias
ECG’s and ? telemetry
Those who DO NOT suffer cardiopulmonary
arrest do well - those who do have a poor
prognosis
All need adequate outpatient referral for
neuropsychiatric follow-up
Ancillary Studies
Most agree that basic laboratory evaluation is
prudent
CBC
UA - rule out myoglobinuria
Chemistries - including renal function
Cardiac Enzymes - rule out cardiac injury
ECG is essential for all patients
Interval changes (esp. QT interval) and ST
changes
Radiographic studies based on the clinical
scenario
In Hospital Treatment
IV Fluids - necessary for all unresponsive,
unstable, or moderately to severely injured
patients
Fasciotomy - generally NOT needed in the
case of keraunoparalysis
Expectant therapy with complete recovery is the
rule, not the exception
Antibiotics - not needed for lightning injuries
themselves BUT may be necessary
depending on the clinical scenario
For example - open fracture
Prevention
Prevention
Avoid high risk situations - check weather
BEFORE trip
Have an evacuation plan in place
“30 - 30” rule
Try to seek shelter - tents are poor protection
(metal poles and wet items in tent)
Avoid lone trees, ridge tops, look out
structures, clearings
Crouch down or kneel in forested area with
small trees
Sitting on pack may prevent step voltage
Lightning Safety Position
From the Website: http://www.lightningsafety.noaa.gov/outdoors.htm, accessed 2-7-06
Lightning Safety Group
1998 Recommendations