Management of Lightning Injuries and Severe Storms

R. Darrell Nelson

HENDERSON McGinnis

INTRODUCTION

Lightning and severe storms are natural weather phenomena occurring daily across our entire planet. Because no single agency requires reporting of these phenomena, the true incidence of related injury and death is unknown. In addition to lack of mandatory reporting, self-reporting by the individual may not occur and some subjects of injury may not seek medical treatment. In some instances, individuals found dead outdoors may have suffered a lightning strike and this may not be recognized as the cause of death.

Lightning is consistently among the top four killers from weather-related conditions. Those most at risk of lightning strike are found outdoors participating in sporting events, recreational activities including mountain climbing, golf, ball field games, and water-related activities. Individuals who work primarily outdoors such as farming, construction, and military personnel are also at risk of injury. Lightning may also involve more than one subject as many outdoor activities are done in groups, where lightning can injure multiple people simultaneously with variable severity.

We tend to think of lightning and severe storms as warm weather events, but lightning can occur during snowstorms or even out of a clear blue sky. Under certain conditions during winter storms, sleet and graupel are formed. Graupel is frozen precipitation seen as snow pellets or soft hail. This indicates large differences in electrical potential in the air, large areas of positive and negative charges, which can lead to the formation of lightning strikes.¹^,²

EMS providers encounter injuries from lightning events and severe storms; in fact, EMS will likely be the first medical provider to make contact with a patient of lightning injury. Therefore, they must understand the basic principles of lightning injury, both the subtle and often dramatic presentations of a lightning strike patient, myths associated with lightning injury, the concept of reverse triage, initial care and stabilization, appropriate transport destinations, and prudent advice to the patient who may not wish to seek further medical care. EMS should also serve as an expert resource when providing medical coverage for mass-gathering events where lightning and severe storms are possible as the prevention of injury from lightning strike is paramount. Provider safety is the first priority. EMS providers should have an understanding of how to maintain their own safety and prevent injury from lightning and severe storms.

Definition

Lightning is a form of electrical energy, which is the flow of electrons from a high concentration to a low concentration. The difference between the high and low concentration of electrons is the potential or volts, represented by the abbreviation V. When electrons move or flow, this is called the current that is represented by the abbreviation I. Electrons flow over time and through an object or the air. When electrons or electricity moves through the human body, it encounters resistance, or impedance to flow, and is represented by the abbreviation R. The resistance to electrical flow generates heat with subsequent injury and burns to the tissue. Flow is one of the most important determinants of injury, with high-voltage injuries usually causing increased morbidity since voltage is directly related to current. The longer tissue is exposed to current, typically the more injury sustained. The following equation is helpful to highlight the relationships of current, voltage, and injury. Q (heat generated) = I × V × t (time duration).³

Electrons move by way of two different paths or circuits. Alternating current, or AC, is the flow of electrons in a cyclical fashion while direct current, or DC, is the flow of electrons in a one-way fashion. AC is represented by household electricity,
typically on the order of either 110 or 240 V in the United States and 220 to 240 V in Europe. Batteries, railways, automobiles, and defibrillators represent DC current. Lightning is neither AC nor DC current and can be described as a unidirectional massive current measured in millions of volts lasting over just 1 or 2 ms.⁴

Electrical injuries result from the direct damage of organs and tissue by the electrical current, the conversion of electricity into heat causing burns, and blunt trauma. The extent and type of injury depends on multiple factors, including whether it is AC or DC current, the path of the current, its voltage, the resistance of the skin, and the duration of the contact.³ The flow of electrical energy follows the path of least resistance. In the human body, the resistance to electrical flow from least to greatest is nerves < blood < muscle < skin < fat < bone (Table 18.1).³

Lightning is the discharge of electrical energy in the air. Thunder is the result of a shock wave created by heating and cooling of the air surrounding the channel of lightning. During a thunderstorm, winds inside the thunderclouds cause water and ice particles to collide. This removes electrons from ice crystals, and larger particles of soft hail gain these electrons. Wind movement redistributes the charges within the thundercloud moving the heavier, more negatively charged soft hail particles to layer in the middle and lower part of the thundercloud. The cloud becomes more negatively charged at the bottom, which causes the earth below the thundercloud to become more positively charged.

As the charge difference increases between the thundercloud and the ground, the negative charges in the lower segment of the cloud start moving toward the more positively charged ground. When this movement occurs, it creates a conductive path to the ground following a zigzag pattern as the negative charge jumps through different segments in the cloud and air. This moving zigzag negative charge is called the leader stroke.²^,⁵ When the negative charge reaches the positively charged ground, a current jumps through the zigzag path creating a brilliant, visible lightning bolt.¹

Table 18.1 Comparisons of Injury/Clinical Findings in Low Voltage, High Voltage, and Lightning

Age/Clinical Finding/Injury	Low Voltage	High Voltage	Lightning
Young children	Frequent	Rare	Rare
Adolescent/adult	Uncommon	Frequent	Rare
Cardiac arrest:
Ventricular Fibrillation	Frequent	Common	Rare
Asystole	Rare	Common	Frequent
Skin burns	Rare	Frequent	Uncommon
Deep tissue burns	Rare	Frequent	Rare
Cataracts	Rare	Uncommon	Uncommon
Myoglobinuria	Rare	Common	Rare
Multisystem trauma	Rare	Common	Uncommon
Surgical amputation	Rare	Common	Rare
Death	Rare	Frequent	Common
Modified from Ota FS, Purdue GF. Emergent injuries to children and adolescents due to electricity and lightning strikes. Pediatr Emerg Med Pract. 2005;2(8):4.

Scope of Discussion

This discussion will focus mainly on the prevention of lightning strike and the initial recognition and stabilization of the lightning subject, appropriate facility destinations, and provider safety. We will discuss how EMS responds to both single and multiple patient of lightning injury highlighting the concept of reverse triage. While electrical injuries encompass lightning, the discussion of injuries from all electrical sources is beyond the scope of this chapter.

We will also discuss preparation of EMS facing severe storms as well as provider safety. However, full discussion of the response to severe storms from an emergency management perspective and disaster response is beyond the scope of this discussion.

EPIDEMIOLOGY

Lightning strikes the earth greater than 100 times each second—eight million times each day—with over 50,000 thunderstorms occurring daily around the world (Figure 18.1).⁶ Deaths from lightning injury, both direct and indirect, from 1968 to 2010 have decreased significantly in both males (by 78.6%) and females (by 70.6%). During this period, 3,389 deaths from lightning occurred with an average of 79 deaths annually. This
total includes lightning as the underlying cause of death and includes both direct and indirect strikes.⁶

FIGURE 18.1. Lightning over desert.

The chance of being struck by lightning is about one in 960,000 to one in 1,190,000. The chance of being struck by lightning in your lifetime is about one in 12,000.⁷ From 2006 to 2013, 261 people were struck and killed by lightning in the United States. About 66% of these were engaged in outdoor activity. Eighty-one percent of all fatalities were male and 90% of all deaths involved fishing and outdoor sports. June, July, and August are the peak months for lightning injuries across the United States: more than 70% of all lightning deaths occur within these months. During the day cloud-to-ground lightning is most common in the afternoon with nearly 50% of all strikes occurring between noon and 6:00 PM. Internationally, an estimated 24,000 fatalities and 240,000 injuries occur from lightning strikes.⁴^,⁸

Table 18.2 Lightning Fatalities Compared to Other Weather-Related Fatalities 2010-2015

Year	Lightning	Male	Female	Tornado	Flood	Hurricanes
2010	29	22	7	45	103	0
2011	26	19	7	553	113	9
2012	28	25	3	70	29	4
2013	23	17	6	55	82	1
2014	26	21	5	47	38	0
2015	27	16	11	36	176	14
Data from NWS Weather Fatality, Injury and Damage Statistics. National Weather Service website. http://www.nws.noaa.gov/om/hazstats.shtml. May 11, 2017. Accessed May 23, 2017.

Injuries sustained from lightning strikes during activity occurring from greatest to least are fishing > camping > boating > beach activity > soccer > golf.⁹ Texas, Florida, and the Gulf of Mexico now comprise the largest number of deaths, whereas between 1968 and 1985, Wyoming and New Mexico had the highest number of deaths due to lightning (Table 18.2).⁹

Lightning strikes occur in six fashions.

First is direct strike, where the subject becomes part of the main lightning channel or within the path of the negatively charged thundercloud and the ground. While this is not the most common mode, it is usually the most deadly.

Second is called the side flash or side splash where lightning strikes a taller object near the subject and a portion of the current jumps over to the subject. This may occur when a person seeks shelter at the base of a tree or other tall objects. Third is ground current exposure. When lightning strikes a tall object the current moves down the object and spreads over the surface of the ground. This ground current can affect a large area and results in most lightning deaths and injuries. The ground current enters the body by contact points such as both legs. The greater the distance between the contact points, the greater the potential for serious injury or death.

A fourth way, documented in case reports, is the subject becoming part of the upward streamer or leader stroke. Fifth is conduction, or contact. This causes most indoor injury and death as the current from lightning is conducted through metal wires, plumbing, metal surfaces, electrical outlets, water faucets, showers, corded phone lines, windows, and doors.

Finally, the subject can experience a blast injury. Thunder, or the blast effect, can cause either primary or tertiary blast injury. Primary blast injury may rupture tympanic membranes and tertiary injury may present as blunt trauma when the subject falls or is thrown.¹⁰^,¹¹

CLINICAL MANAGEMENT

Lightning strikes cause death in about 10% of cases in developed countries. About 74% of subjects suffer permanent injury
and sequelae, though this is controversial, with some studies reporting much less permanent injury. Cardiac arrest, central nervous system (CNS) injury, chronic pain, superficial burns, ocular (eye) burns and cataracts, ruptured tympanic membranes, memory deficits, anxiety, irritability, aphasia, sleep disturbance, and posttraumatic stress disorder (PTSD) are all associated with lightning injury.¹²

Lightning injury primarily affects the cardiovascular system and the CNS. The integumentary system, the musculoskeletal system, the eyes, and the ears may also be affected. In general, the subject of a lightning strike should be treated as a blunt trauma patient with attention to spinal cord protection as warranted. Lightning may strike multiple individuals simultaneously causing a multi-causality incident. When faced with multiple patients of lightning strike, the EMS provider must utilize the important concept of reverse triage.

When EMS is faced with multiple patients, the provider must quickly determine how to deploy the limited resources immediately available to affect the greatest good for the greatest number of patients. As you approach the injured, call out and ask those who can walk to begin walking toward you, directing them to a safe area you have designated, and instruct them to remain in that area. Next call out to those who cannot walk, but can hear and respond to your commands, by asking them to wave their hands in the air. Those patients who do not walk or wave are considered to be the most severely injured or possibly dead. You move quickly to those patients and assess the need for lifesaving interventions. During this initial assessment, if the patient is not breathing, they are categorized as expectant or dead and you move to other victims for continued assessments. This is an example of the traditional SALT triage: Sort, Assess, provision of Lifesaving interventions, and Treat or Transport. However, this is not the ideal form of triage to use in a lightning scenario.¹³

Centers for Disease Control and Prevention proposes a counterintuitive approach to mass casualties involving patients of lightning strike called reverse triage.¹⁰ The majority of deaths from lightning strike are from cardiac arrest caused by lightning’s massive current essentially defibrillating the heart, resulting in asystole or ventricular fibrillation. The defibrillation also causes the brain’s respiratory centers in the medulla to stop working. As with conventional cardiac defibrillation, the heart may return to an organized rhythm; however, the respiratory center is slower to reactivate and the chest wall musculature may also experience transient paralysis. So the patient may have return of spontaneous circulation only to die of hypoxia leading to a second cardiac arrest.⁶

Unresponsive patients secondary to lightning strike should be resuscitated vigorously as they may require rescue breathing and/or cardiopulmonary resuscitation (CPR), which have a high likelihood of survival even with prolonged downtime periods.¹⁴ Patients who initially survive a lightning strike typically have full recovery, emphasizing the important role for reverse triage in these situations: “resuscitate the dead first.”

CNS injury is common in subjects of lightning strike. CNS injuries are divided into four categories and include immediate and transient injury; immediate and prolonged or permanent injury; possible delayed neurologic syndromes; and trauma from falls, burns, or blasts. The first category of immediate and transient injuries is common. Eighty percent of patients have paresthesias (burning, prickly pain, tingling) and general weakness. Loss of consciousness occurs in 75% of patients. Other symptoms include confusion, amnesia, headaches, and keraunoparalysis (Charcot’s paralysis). Keraunoparalysis is unique to lightning injury and is thought to be due to a catecholamine surge manifested by transient paralysis, pallor, vasoconstriction, hypertension, and loss of sensation. It typically impacts the lower extremities primarily and lasts one to several hours. Keraunoparalysis is unique to lightning injury, and lower extremity weakness should be considered a more general injury such as spinal injury, stroke, or intracerebral injury until proven otherwise.¹⁰

The second category of immediate and prolonged or permanent neurologic injury include hypoxic injury to the peripheral nervous system or neuropathy, intracranial hemorrhage, post cardiac arrest cerebral injury or infarction, and damage to the cerebellum. Spinal and peripheral nerve damage is uncommon, unlike other high-voltage electrical injuries.¹⁰

The third category of possible delayed neurologic syndromes includes symptoms possibly related to the lightning injury, but manifesting in a delayed fashion. These include a wide variety of motor neuron diseases and movement disorders such as amyotrophic lateralizing sclerosis or Parkinson’s disease.¹⁰

The fourth category involves trauma from falls, burns, or blast injuries. Lightning injury may also be associated with long-term neuropsychological complaints. Symptoms may include fatigue, lack of energy, poor concentration, irritability with emotional lability, and PTSD in about 30% of patients. These are divided into functional or behavioral categories. Patients and families can be referred to one of several support networks such as Lightning Strike and Electric Shock Survivors International, Inc (http://www.lightning-strike.org).⁴^,⁸

Eye and ear injuries can also occur. Tympanic membrane rupture is present in about 50% of lightning strike survivors, and patients can also experience vestibular injury and deafness. Lightning strikes create a shock wave capable of inducing tympanic membrane rupture. Note that lightning can travel through telephone wires, creating an ideal circumstance for this type of injury if on a wired phone during a lightning storm. Lightning and other high-voltage electrical injuries can also cause cataracts appearing immediately after injury or as late as 4 years after the initial injury.¹⁰ There is some experimental evidence that some of the lightning current enters the eyes, ears, nose, and mouth. Entry into these orifices may also allow a pathway to the brainstem,
which may explain the number of eye and ear symptoms that occur, as well as interruption in respirations.⁴

Four types of injuries, including linear injury, punctate injury, feathering injury, and thermal injury, affect the integumentary system.

Linear burns usually follow areas of high sweat or moisture under the breasts, axilla, groin, and down the center of the chest. Linear burns are usually 1 to 4 cm in diameter presenting immediately or can be delayed over several hours. They are thought to develop following vaporization of water on the skin.¹⁰

Punctate burns are small, circular burns which appear in closely spaced multiples. Some may be full-thickness burns, but due to their small size rarely require treatment. Tips of fingers, toes, and the soles of the feet should be carefully inspected for full-thickness punctate burns as a sign of lightning injury and called the “tip-toe” sign.⁵^,¹⁰

Feathering lesions are also known as Lichtenberg figures or keraunographic markings (Figures 18.2, 18.3, 18.4, 18.5). Lichtenberg figures are pathognomonic for lightning injury, but are not always present and are transient, lasting only a few hours. No damage to the epidermis or dermis occurs and they are not considered a thermal injury. They appear as fern-like, branching lesions on the skin. These lesions are hypothesized to be caused by blood escaping into the subcutaneous tissue and require no treatment.¹⁰

Identification

Often the subject of a lightning strike will present overtly either by way of personal account of the experience or the presence of a bystander as a witness to the event. Patients found unresponsive
outdoors should have lightning strike included in their differential. Also patients found unresponsive indoors should have lightning strike included in their differential, knowing that lightning current can propagate through plumbing, electrical wiring, plumbing fixtures, showers, and even telephones.

FIGURE 18.2. Lichtenberg figure on back of adolescent. Courtesy of Dr. Mary Ann Cooper, with permission.

FIGURE 18.3. Lichtenberg figure on chest of adolescent. Courtesy of Dr. Mary Ann Cooper, with permission.

FIGURE 18.4. Close-up of Lichtenberg figure on back of adolescent. Courtesy of Dr. Mary Ann Cooper, with permission.

FIGURE 18.5. Burn from metal necklace in contact with chest and neck of adult. Courtesy of Dr. Mary Ann Cooper, with permission.

The EMS provider must maintain a high index of suspicion, as not all lightning injuries will present in an obvious fashion. While high-voltage injuries are arbitrarily defined as greater than 600 or 1,000 V, lightning typically involves voltages greater than 200,000 V and even up to 30 million volts. Ironically, this extremely high voltage often will not manifest as obvious injuries on exam. During a lightning strike, the electrical current flashes over the subject with the current only lasting milliseconds, often leaving no discernable physical findings as total current contact time dictates injury severity. If the subject has wet skin this may further decrease the risk of internal injury as this may provide a path for the current to travel over the body. This flashover explains why some patients of lightning strike have no obvious injuries, as well as why some patients literally have their clothes “blown off” as the moisture on the skin combusts. This phenomenon is especially common for socks and shoes, due to high sweat content of feet (Figure 18.6). This large current however produces a pulsed magnetic field that can induce injury in nearby persons and also disrupt the cardiovascular system and neurologic systems.¹⁵

In some areas of the United States, especially in more rural areas, paramedics or other EMS providers are serving as medical examiners or coroners and are responsible for investigating unnatural deaths. In the case of potential lightning injury, a forensic style investigation will serve the provider when dealing with a salvageable patient as well as in the case of a decedent. Some important questions to consider in the case history and scene investigation are listed in Tables 18.3 and 18.4.

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