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Environmental and weapon-related electrical injuries
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Environmental and weapon-related electrical injuries
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Literature review current through: Sep 2017. | This topic last updated: Oct 02, 2017.

INTRODUCTION — Electrical injuries are relatively common, nearly always accidental, and generally preventable. The direct effect of electrical current, conversion of electrical to thermal energy, and blunt mechanical trauma can result in tissue destruction and organ dysfunction. Appropriate therapy includes management of trauma and a detailed physical assessment. Multiple surgical interventions, including fasciotomy and skin grafting, and prolonged supportive care may be required.

Electrical injuries will be reviewed here. The evaluation and management of burns, general aspects of trauma management, and injuries related to electrosurgery are discussed separately. (See "Emergency care of moderate and severe thermal burns in adults" and "Emergency care of moderate and severe thermal burns in children" and "Initial management of trauma in adults" and "Overview of electrosurgery".)

EPIDEMIOLOGY

General — Electrical burns and lightning injuries are estimated to result in more than 3000 admissions to specialized burn units each year in the United States, and account for 3 to 4 percent of all burn-related injuries [1-4]. Up to 40 percent of serious electrical injuries are fatal, resulting in an estimated 1000 deaths per year [4-6].

There is a bimodal distribution of environmental electrical injuries with respect to age. Work-related injuries in adults, and accidents in children, account for most electrical injuries. Incidence is increased among children younger than six years, often because of contact with electric cords or outlets [7,8]; older children generally suffer high-voltage injuries from power lines while climbing trees or utility poles [8,9].

The incidence of electrical injuries decreases through the teenage years and increases again as adults enter the workplace. Together, construction and electrical workers account for about two-thirds of all electrical injuries. Electrical injuries are the second leading cause of occupation-related deaths in the United States. There is an approximately 2:1 male to female ratio in childhood; among adults, more than 90 percent of victims are men [1,5,6,10,11].

Lightning — Lightning injuries, a small subset of electrical injuries, are responsible for an average of 300 injuries and 100 deaths per year in the United States [3,12-14]. It is likely that lightning-related fatalities and hospitalizations are underestimated [15]. Approximately 30 percent of those struck by lightning die and up to 74 percent of survivors may have permanent disabilities [4,12,16]. Two-thirds of lightning-associated deaths occur within one hour of injury and are generally due to a fatal arrhythmia or respiratory failure [17,18].

There is significant temporal variation in lightning-related fatalities; over 90 percent occur during the spring and summer, and roughly 70 percent occur during the afternoon and early evening [17,19]. More than one-half of all lightning-related fatalities occur while people are engaged in outdoor recreational activities; another 25 percent happen when working outdoors [17,19].

The victims of most fatal lightning injuries are young men. According to data from the Centers for Disease Control (CDC), between 1980 and 1996, 85 percent of 1318 people reported killed by lightning were male, and 68 percent were aged 15 to 44 years. The greatest number of deaths attributable to lightning occurred in Florida and Texas, but New Mexico, Arizona, Arkansas, and Mississippi had the highest incidence (9 to 10 per 10,000,000) [17].

Electrical weapons — Electrical weapons, including the stun gun and the Taser, have been developed for use by law enforcement and security personnel to provide less lethal alternatives to conventional weapons, including handguns [20]. These devices deliver bursts of high-voltage, low-amperage direct current, either through a handheld device (stun gun) or through a hook and wire system fired using compressed gas (Taser) [21]. Electrical weapons are widely available and have been used for criminal purposes and torture [20].

A systematic review of the clinical studies of electrical weapons found no evidence that they cause "dangerous laboratory abnormalities, physiologic changes, or immediate or delayed cardiac ischemia or arrhythmias" when exposure lasts 15 seconds or less [22]. Subsequent reviews and studies have reported similar results [22-24]. A study of electrical weapons use against minors (n = 100; median age 16 years) reported no significant injuries [25]. We agree with the authors of two systematic reviews, who conclude that prolonged observation and diagnostic testing are not necessary in patients who are otherwise asymptomatic and alert following such an exposure [22,23].

Nevertheless, in rare instances, fatal arrhythmias have been reported in patients shot by electrical weapons [26,27]. One report noted fatal cardiac arrest in 3 of 218 people who received medical attention within 5 to 25 minutes following Taser injury [26]. This study likely overestimates the risk of cardiac arrest, since only those individuals who required medical attention were included in the analysis. Concurrent intoxication with cocaine, methamphetamine, phencyclidine (PCP) or other stimulants is common among those subdued by law enforcement with electrical weapons and may increase the risk of cardiac arrhythmia, as may preexisting cardiovascular disease [21,23,26,28]. (See "Evaluation and management of the cardiovascular complications of cocaine abuse" and "Methamphetamine: Acute intoxication" and "Phencyclidine (PCP) intoxication in adults".)

People can be injured if they fall after being "stunned," and such patients should be carefully examined, including diagnostic studies as indicated. Significant injuries reported in association with electrical weapons are rare, but may include cutaneous burns, lacerations, rhabdomyolysis, testicular torsion, ocular injury, and miscarriage [21,29]. Evaluation of the trauma patient is discussed separately; the management of cutaneous injuries is supportive and is similar to the treatment of other types of electrical injuries. (See "Initial management of trauma in adults" and 'Management' below.)

PHYSICS OF ELECTRICITY — Electricity is defined as the flow of electrons between points of high concentration to points of lower concentration (or potential). The electrical current is the volume (or actual number) of electrons that flow between these points per second, measured in amperes. In an alternating current (AC), the direction of flow of electrons changes on a cyclical basis. Standard household current is AC alternating at 60 cycles per second. With direct current (DC), the direction of flow remains constant. DC current is found in batteries, railway tracks, automobile electrical systems, and lightning.

The force that drives the electrons across the potential difference is the voltage (V). Resistance (R) describes the hindrance to flow. The interrelationship among current (I), voltage, and resistance is described by Ohm's law:

I  =  V/R

Stated another way, current is directly proportional to the voltage and inversely proportional to resistance.

MECHANISM OF INJURY — Injuries due to electricity occur by three mechanisms:

Direct effect of electrical current on body tissues

Conversion of electrical energy to thermal energy, resulting in deep and superficial burns

Blunt mechanical injury from lightning strike, muscle contraction, or as a complication of a fall after electrocution

The primary determinant of injury is the amount of current flowing through the body. Clinically, contact with a 120 V circuit carrying a 1 milliampere (mA) current is imperceptible to most persons, 3 mA leads to mild tingling, and 10 to 12 mA leads to pain. One hundred mA directed across the heart can cause ventricular fibrillation (table 1) [30-32]. In addition, the voltage, resistance, type of current (AC or DC), the current pathway, and duration of contact all influence the extent of injury [33].

The tissue damage inflicted by most electrical currents can be primarily attributed to the thermal energy (or heat) generated by the current, as predicted by Joule's law:

 Heat = current (I) x voltage (V) x time of contact (t)

         = I x V x t
         = I x (I x R) x t (from Ohm's Law)
         = I2 x R x t

Resistance is a function of the area of contact, pressure applied, and the presence of moisture. Tissues with higher resistance have a tendency to heat up and coagulate, rather than transmit current. Skin, bone, and fat have high resistances, while nerves and blood vessels have lower resistances.

Of all organ systems, the skin has the greatest effect on the severity of an electrical injury. Dry skin has a resistance of approximately 100,000 ohms; however, this drops to less than 2500 ohms when the skin is dampened [9]. Thus, in some cases, a lower voltage applied to tissue with low resistance can generate more current and be more damaging than higher voltage applied to tissue with high resistance.

DC current tends to cause a single muscle spasm that throws the victim from the source. This results in a shorter duration of exposure, but a higher likelihood of associated trauma. In contrast, AC repetitively stimulates muscle contraction. Often, the site of exposure is at the hand, and because the flexors of the arm are stronger than the extensors, the victim may actually grasp the source, prolonging the duration of contact and perpetuating tissue injury.

The amount of AC needed to cause injury varies in proportion to its frequency, expressed in cycles per second or hertz (Hz). Skeletal muscle can become tetanic with frequencies between 15 and 150 Hz, and although a 20 mA current may not be perceptible at 10 Hz, the same current may cause respiratory paralysis or ventricular fibrillation at lower frequencies [9,34,35].

CLASSIFICATION OF INJURY — As voltage is often the only variable known with certainty, electrical injuries are generally classified as being high voltage (>1000 V) or low voltage (<1000 V) (table 2). Voltage in high-tension power lines is greater than 100,000 V, while the typical voltage delivered to homes is either 110 V (North America) or 220 V (Europe and Asia). In contrast, lightning strikes are associated with a potential difference between the atmosphere and the ground in excess of 10 million volts [9].

Clinically, there are four classes of electrical injury:

The classic injury pattern develops when the body becomes part of a circuit and is usually associated with entrance and exit wounds. These wounds generally do not help predict the path of the current, and the skin findings can significantly underestimate the degree of internal thermal injury.

Flash (or arc) burns occur when the current arc strikes the skin, but does not enter the body.

Flame injuries from clothing catching fire in the presence of an electrical source.

Lightning injury is caused by a DC current exposure that lasts from 1/10 to 1/1000 of a second, but often has voltages that exceed 10 million V [4,9,36]. Peak temperature within a bolt of lightning rises within milliseconds to 30,000 Kelvin (five times hotter than the sun), generating a shock wave of up to 20 atmospheres induced by the rapid heating of the surrounding air [9,36,37]. This shock wave then can be transmitted through the body and result in mechanical trauma.

Because of the variability of tissue resistance, surface area, and volume of tissue exposed, it is extremely difficult to predict the actual course of current flow and to infer the type and extent of injuries to internal organs. Careful clinical assessment, recognizing that surface findings may underestimate the extent of tissue damage or necrosis, should be used to guide management.

ORGAN INVOLVEMENT — The clinical manifestations of electrical injuries range from mild superficial skin burns to severe multiorgan dysfunction and death.

Cardiac — The overall estimate of arrhythmia following electrical injury is approximately 15 percent; most of these are benign and occur within the first few hours of hospital admission [38,39]. However, acute electrical cardiac injury can result in sudden cardiac arrest due to asystole (usually with DC current or lightning) or ventricular fibrillation (AC current) prior to hospitalization [40]. Ventricular fibrillation is the most common fatal arrhythmia, occurring in up to 60 percent of patients in whom the electrical current pathway travels from one hand to the other [3,41]. (See "Advanced cardiac life support (ACLS) in adults", section on 'Ventricular fibrillation and pulseless ventricular tachycardia'.)

Spontaneous return of sinus rhythm has been noted after asystole in cases of electrical injury, but because respiratory paralysis lasts longer, the rhythm may degenerate to ventricular fibrillation due to hypoxia. Atrial dysrhythmias, first and second-degree heart block, and bundle branch blocks have been noted as well [3,39]. It is postulated that the anterior location of the right coronary artery leaves the sinus and AV nodal arteries more vulnerable. Changes in the ST segment and T wave, as well as conduction disturbances, generally resolve without specific treatment. (See "Basic approach to delayed intraventricular conduction".)

Damage to the myocardium is uncommon, but can occur as a result of heat injury or myocardial contusion resulting from the shock wave of a lightning strike. Cardiac contusion is the most common pathologic cardiac finding, while myocardial infarction is rare [42]. Other rare cardiac manifestations include coronary spasm and myocardial rupture due to coagulation necrosis [37,43-47]. The evaluation and management of cardiac contusion and the clinical manifestations of myocardial rupture are described separately. (See "Cardiac injury from blunt trauma" and "Mechanical complications of acute myocardial infarction".)

Renal — Rhabdomyolysis may result from massive tissue necrosis and can be complicated by pigment-induced acute kidney injury. In addition, hypovolemia due to extravascular extravasation of fluid can lead to prerenal azotemia and acute tubular necrosis. The diagnosis of these complications is discussed separately. (See "Clinical manifestations and diagnosis of rhabdomyolysis" and "Clinical features and diagnosis of heme pigment-induced acute kidney injury", section on 'Causes of rhabdomyolysis'.)

Neurologic — Damage to both the central and peripheral nervous systems can occur after electrical injury. Manifestations may include loss of consciousness, weakness or paralysis, respiratory depression, autonomic dysfunction, and memory disturbances [48-50]. Sensory and motor findings due to peripheral nerve damage are common. Unless the patient attempts to ambulate, lower-extremity weakness may go undiagnosed initially. Of note, the deficits may be "patchy" with the sensory deficits not corresponding to the motor findings. The clinical manifestations of neurologic damage from high-voltage exposures may be delayed for days to months after the injury.

Keraunoparalysis is a temporary paralysis specific to lightning injuries that is characterized by blue, mottled, and pulseless extremities (lower more commonly than upper). These findings are felt to be secondary to vascular spasm and often resolve within hours but can be permanent [50,51].

Patients hit by lightning may present with pupils that are fixed and dilated or asymmetric due to autonomic dysfunction. As a result, fixed, dilated, or asymmetric pupils should not be used as a reason to stop resuscitation [9]. Complications of lightning strikes can include hypoxic encephalopathy, intracerebral hemorrhage, cerebral infarction, and spinal fractures have been reported [52,53]. (See 'Cardiopulmonary resuscitation' below.)

Cataracts, hyphema, vitreous hemorrhage, and optic nerve injury can occur, particularly following lightning injury [9,50]. In addition, 50 to 80 percent of patients struck by lightning sustain ruptured tympanic membranes [42,54,55]. Sensorineural hearing loss, tinnitus, vertigo, and injury to the facial nerve have all been described [54,56]. (See "Cataract in adults" and "Approach to the adult with acute persistent visual loss", section on 'Vitreous hemorrhage' and "Ear barotrauma" and "Traumatic hyphema: Clinical features and diagnosis" and "Traumatic hyphema: Management".)

Skin — Superficial, partial-thickness, and full-thickness thermal burns can occur following electrical injury. It has been estimated that exposure to 20 to 35 mA per mm2 of skin surface for 20 seconds raises the skin temperature to 50ºC, leading to blistering and swelling [57]. Seventy-five mA per mm2 for the same period raises the temperature to 90ºC [34], and may cause more severe burns and charring. (See "Emergency care of moderate and severe thermal burns in adults" and "Treatment of minor thermal burns".)

In a postmortem study of 220 fatal electrical injuries, 57 percent of low-voltage and 96 percent of high-voltage victims had visible electrical burns [35]. Burns are most common at the site of electrical contact and at places in contact with the ground at the time of injury. The degree of external injury cannot be used to determine the extent of internal damage, especially with low-voltage injuries. Seemingly minor surface burns may coexist with massive muscle coagulation and necrosis, as well as internal organ injury. Patients with cranial burns or leg burns from lightning are at higher risk for death than others struck by lightning, possibly because more current has passed directly through the body [58].

A unique type of burn seen with electrical injury is the "kissing burn". This occurs at flexor creases, where the flexor surfaces adjacent to a joint touch.

Oral burns can occur in young children from sucking or chewing on extension cords. Delayed hemorrhage from the labial artery may occur when the eschar separates, sometimes days after the injury. Cosmetic defects may also occur, particularly when the commissure is involved.

The incidence of superficial surface burns is high in victims of lightning injury, but deep burns are unusual [50]. One series of patients following lightning strike noted an 89 percent incidence of burns, but only 5 percent were deep [58]. The low incidence of deep burns is in part due to the short duration of contact and the "flashover effect", which occurs when the current travels on the skin surface and is discharged to the ground. This can result in the formation of branching cutaneous "feather" lesions, also called Lichtenberg figures, which fade rapidly but are pathognomonic of lightning injury (picture 1) [59].

Musculoskeletal — Because bone has the highest resistance of any body tissue, it generates the greatest amount of heat when exposed to an electrical current. Thus, the areas of greatest thermal injury are often the deep tissue surrounding long bones, potentially resulting in periosteal burns, destruction of bone matrix, and osteonecrosis [9]. (See "Osteonecrosis (avascular necrosis of bone)".)

In addition to burn-related injuries, bones can fracture from falls, blast injuries, or under the stress of repetitive tetanic muscle contractions. It is reasonable to obtain imaging studies of the cervical spine to assess for fracture in patients with significant electrical injuries or an altered mental status.

Deep electrothermal injury can result in tissue necrosis and edema and the development of acute compartment syndrome, leading to rhabdomyolysis and/or visceral injury. (See 'Myoglobinuria' below and "Acute compartment syndrome of the extremities" and "Crush-related acute kidney injury (acute renal failure)".)

Vascular, coagulation system, and other injuries — Vascular injury can result from an acute compartment syndrome or the electrical coagulation of small blood vessels. Such vascular trauma is more common following electrical than lightning-related injury. (See "Acute compartment syndrome of the extremities".)

Delayed arterial thrombosis as well as aneurysm formation and rupture have been reported following electrical injury and are due to medial coagulation and necrosis [41,60-62].

Damage to internal organs, including the lungs, stomach, small intestine, and colon, is uncommon. When abdominal involvement does occur, it can be complicated by fistula formation, perforation, secondary polymicrobial infection, sepsis, and death [63,64]. (See "Evaluation and management of suspected sepsis and septic shock in adults".)

Patients who fall or are thrown as a result of a severe electrical exposure may sustain severe injuries and must be carefully evaluated. (See 'Trauma resuscitation and neurologic evaluation' below.)

PHYSICAL EXAMINATION — Patients presenting for medical care following a significant electrical exposure are susceptible to a wide range of injuries, including those sustained from falling or being thrown, and should be carefully examined, with particular attention paid to the organ systems most often affected. Following severe electrical exposures, some injuries may not be apparent initially and frequent reassessment is essential. (See 'Organ involvement' above.)

Important areas to assess include the following:

Airway, breathing, and circulation

Cardiovascular function: assess cardiac rhythm; examine pulses

Skin: Inspect for burns; look for blisters, charred skin, and other lesions; pay attention to skin creases, areas around joints, and the mouth (particularly in young children)

Neurologic function: assess mental status, pupillary function, strength and motor function, and sensation

Ophthalmologic: assess visual acuity; inspect the eyes, including a funduscopic examination

Ear, nose, and throat: inspect the tympanic membranes; assess hearing

Musculoskeletal: inspect and palpate for signs of injury (eg, fracture, acute compartment syndrome), and be certain to examine the spine

MANAGEMENT

Cardiopulmonary resuscitation — Prolonged cardiopulmonary resuscitation (CPR) should be undertaken following electrical injury regardless of the initial rhythm, since most victims are young and good outcomes have been noted even among patients with asystole [3,65]. For this reason and because patients who do not sustain cardiac arrest generally survive without intervention, usual triage priorities are reversed if multiple victims are present: patients without signs of life are treated first [3,50,55,58]. The treatment for particular arrhythmias is unchanged [50]. (See "Advanced cardiac life support (ACLS) in adults" and "Pediatric advanced life support (PALS)" and "Prehospital care of the adult trauma patient".)

Patients can have spontaneous cardiac activity but paralysis of the respiratory muscles. Prompt restoration of gas exchange via a secure airway may prevent secondary cardiac and neurologic dysfunction or death. (See "Basic airway management in adults" and "Advanced emergency airway management in adults" and "Basic airway management in children".)

Lightning injury can result in clinical signs typically associated with severe brain injury (eg, fixed and dilated pupils) but which may not accurately reflect the patient's neurologic status. Therefore, prolonged CPR may be indicated and clinical judgement should be used to determine the appropriate duration of resuscitative efforts. (See 'Neurologic' above and "Prognosis and outcomes following sudden cardiac arrest in adults", section on 'Factors affecting out-of-hospital SCA outcome'.)

Trauma resuscitation and neurologic evaluation — The patient who suffers a serious electrical burn or lightning strike has sustained significant trauma. Appropriate trauma resuscitation should be performed, beginning with a rapid assessment of the airway and cardiopulmonary status. Coexisting smoke inhalation or airway burns must be excluded. Cervical spine immobilization and clearance are necessary, and tetanus prophylaxis should be administered. Coma or neurologic deficit, including alterations in mental status, should prompt brain and spine imaging. A careful secondary survey is needed once the initial resuscitation is complete. (See "Initial management of trauma in adults" and "Inhalation injury from heat, smoke, or chemical irritants".)

Cardiac injury — The survivor of a high-energy (>1000 V) injury should be evaluated with and electrocardiogram (ECG) and have cardiac and hemodynamic monitoring due to the high incidence of arrhythmia and autonomic dysfunction, especially if there have been arrhythmias in the field or emergency department, loss of consciousness, or if the initial ECG is abnormal [50]. In many cases, telemetry is adequate. Patients with signs of instability (eg, recurrent arrhythmia or hypotension) require more intensive monitoring.

Serum CK-MB measurements and ECG changes are poor measures of myocardial injury following electrical trauma [37,43-47,50]. The diagnostic and prognostic value of cardiac troponin has not been formally studied in this setting. However, some researchers believe that troponin-I levels and echocardiography can detect myocardial injury after electric shock [66]. The best method to assess myocardial damage following electrical injury remains uncertain and is best determined in consultation with a cardiologist.

Fluid resuscitation — Patients with soft tissue injuries from a severe electrical exposure often require aggressive IV fluid replacement, especially if there are signs of muscle necrosis; those with lightning injuries typically require less volume than patients with thermal burns [9]. Parkland and similar formulas used for fluid resuscitation following thermal burns should not be used in victims of electrical injuries, since surface burns may grossly underestimate the extent of injury. (See "Emergency care of moderate and severe thermal burns in adults", section on 'Fluid resuscitation'.)

The approach to fluid resuscitation is similar to that used for the prevention of acute kidney injury from heme pigments (ie, myoglobinuria) and is discussed separately. Fluid resuscitation for patients with severe soft tissue injuries is comparable to that used for major crush injuries. Given the risk of hyperkalemia, IV fluids containing potassium should be avoided. (See "Prevention and treatment of heme pigment-induced acute kidney injury", section on 'Prevention' and "Crush-related acute kidney injury (acute renal failure)".)

Acute hypotension should prompt a search for thoracic or intraabdominal bleeding secondary to blunt trauma. (See "Initial evaluation and management of shock in adult trauma".)

Large fluid shifts can occur following electrical injury, and clinicians should pay close attention to volume status and electrolytes throughout the course of management. Physiologic measures, including heart rate, blood pressure, and urine output, are useful in guiding resuscitation. Central venous pressure monitoring may be beneficial in patients with more severe injuries. Urine output in adults should be maintained at over 100 mL per hour (for young children, a goal of approximately 1.5 to 2 mL/kg per hour is reasonable); serum electrolyte concentrations, particularly potassium, should be measured approximately every two to four hours early during management, depending upon the prior value, renal function, and clinical status.

The combination of aggressive fluid repletion and restrictive surface burns can lead to the development of increased intraabdominal pressure and the abdominal compartment syndrome. (See "Abdominal compartment syndrome in adults".)

Cerebral salt wasting has been reported as a complication of lightning-related electrical injuries [67]. (See "Cerebral salt wasting".)

Myoglobinuria — Patients should be monitored for the development of acute compartment syndrome, rhabdomyolysis, and acute kidney injury. The goal should be to maintain adequate urine output to minimize intratubular cast formation until pigment has cleared from the urine [4,9]. However, in patients who develop acute kidney injury and are oliguric or anuric, care must be taken to avoid massive fluid overload from excessive fluid administration. Recognition and management of acute compartment syndrome and the prevention and treatment of myoglobinuria are reviewed separately. (See "Acute compartment syndrome of the extremities" and "Prevention and treatment of heme pigment-induced acute kidney injury".)

Radionuclide imaging with technetium-99 has been used to identify nonviable muscle following severe electrical injury; however, it is not clear if the results have an impact on treatment decisions or mortality [68-70]. Persistent myoglobinuria may necessitate amputation of the injured extremity in some cases. (See "Severe extremity injury in the adult patient".)

Skin wounds — In general, wounds are treated in a similar manner to flame or other thermal burns. However, Parkland and similar formulas used for fluid resuscitation following thermal burns should not be used in victims of electrical injuries, since surface burns may significantly underestimate the extent of injury. Patients with burns may require transfer to a burn unit and treatment with fasciotomy, escharotomy, extensive skin reconstruction, or limb amputation. Topical antibiotic prophylaxis is indicated for non-superficial burns. The value of prophylaxis with intravenous antibiotics is controversial. Some physicians give penicillin to cover Clostridial species since myonecrosis has been reported [41]. (See "Emergency care of moderate and severe thermal burns in adults" and "Emergency care of moderate and severe thermal burns in children".)

Gastrointestinal injury — Gastrointestinal injury is uncommon, but persistent ileus, abdominal pain, or tenderness should prompt abdominal imaging and surgical consultation [9]. Injury to abdominal organs, possibly caused by a vascular insult, can occur and may require laparotomy. As with mesenteric ischemia, symptoms and signs of injury may be delayed and diagnosis can be difficult.

Patients have a greater chance of developing gastric ulcers following electrical burns (Curlings ulcers) than with other burns [4,9,71]. Therefore, it is prudent to provide prophylactic therapy, particularly in patients with severe burns and those who cannot or are not permitted to take food by mouth (NPO). (See "Stress ulcer prophylaxis in the intensive care unit".)

Miscellaneous — After stabilization, careful otologic and audiometric examinations may reveal injuries that are amenable to delayed repair [4,9,58]. Ophthalmologic evaluation is warranted because of the potential for delayed development of cataracts, particularly following lightning injury [9]. Cataracts generally develop several days after injury, though there may be a lag of up to two years [71,72]. Early institution of physical therapy may prevent deterioration in functional status, and psychiatric consultation may be required for patients who develop behavioral disturbances or posttraumatic stress disorder [52,73]. (See "Posttraumatic stress disorder in adults: Epidemiology, pathophysiology, clinical manifestations, course, assessment, and diagnosis" and "Pharmacotherapy for posttraumatic stress disorder in adults".)

DIAGNOSTIC STUDIES — No clear guidelines exist about what studies to obtain following electrical injury and to a large degree this must be determined clinically on a case by case basis. For patients who warrant observation or admission to the hospital following such an injury, we generally obtain the following studies:

Electrocardiogram

Basic serum electrolytes (including potassium and calcium)

Creatine phosphokinase (to detect muscle injury)

Serum troponin

Basic blood counts

Renal function studies (creatinine and BUN)

Radiographic studies of any region we suspect may have been injured

The role of troponin to assess cardiac injury is uncertain and should be discussed with cardiology. We obtain repeat studies as clinically indicated. For asymptomatic patients with a low-voltage exposure and an unremarkable physical examination, diagnostic testing is generally not necessary. (See 'Disposition' below.)

DISPOSITION — Severely injured patients are admitted to an intensive care setting. Patients with significant electrical burns should generally be transferred to a burn center when stable.

When exposure to high-voltage (>1000 V) is suspected, 12 to 24 hours of cardiac monitoring is prudent despite the apparent absence of injury. Additional indications for monitoring include a history of cardiac disease, active chest pain, or a documented loss of consciousness or arrhythmia in a patient exposed to lower-voltage.

Patients who are asymptomatic after a low-voltage exposure with a normal physical examination do not require ancillary diagnostic tests and can be reassured and discharged [9]. Patients with mild persistent symptoms or minor cutaneous burns and a normal ECG and urinalysis (no hemoglobinuria) can be observed for a few hours and discharged with appropriate follow-up based upon the severity of their wounds and any comorbidities. Obstetric consultation for pregnant patients is reasonable. Placental abruption may be associated with minor trauma, including electrical injuries.

INFORMATION FOR PATIENTS — UpToDate offers two types of patient education materials, "The Basics" and "Beyond the Basics." The Basics patient education pieces are written in plain language, at the 5th to 6th grade reading level, and they answer the four or five key questions a patient might have about a given condition. These articles are best for patients who want a general overview and who prefer short, easy-to-read materials. Beyond the Basics patient education pieces are longer, more sophisticated, and more detailed. These articles are written at the 10th to 12th grade reading level and are best for patients who want in-depth information and are comfortable with some medical jargon.

Here are the patient education articles that are relevant to this topic. We encourage you to print or e-mail these topics to your patients. (You can also locate patient education articles on a variety of subjects by searching on "patient info" and the keyword(s) of interest.)

Basics topic (see "Patient education: Electrical burns (The Basics)")

SUMMARY AND RECOMMENDATIONS

Electrical injuries are relatively common and often preventable. Lightning injuries comprise a small subset of electrical injuries. Injuries from electrical weapons are increasing as these devices become more widely used, but serious injuries resulting from their use are rare. The direct effect of electrical current, conversion of electrical to thermal energy, and blunt mechanical trauma can all result in tissue destruction and organ dysfunction. (See 'Epidemiology' above and 'Electrical weapons' above and 'Physics of electricity' above and 'Mechanism of injury' above.)

The clinical manifestations of electrical injuries range from mild superficial skin burns to severe multiorgan dysfunction and death, depending upon the intensity and the duration of exposure. Following severe electrical exposures, some injuries may not be apparent initially and frequent reassessment is essential. (See 'Organ involvement' above and 'Physical examination' above.)

The organ systems most often affected include:

Cardiac – Arrhythmia can occur; myocardial injury is uncommon. (See 'Cardiac' above.)

Skin – Burns can range from superficial to full-thickness. Do not use surface injuries to gauge the extent of internal injury, which may be extensive despite little skin involvement. Deep injuries are less common with a lightning strike. (See 'Skin' above.)

Musculoskeletal – Severe thermal injury can result in periosteal burns, destruction of bone matrix, and osteonecrosis; massive soft tissue and muscle injury can occur and may lead to rhabdomyolysis or acute compartment syndrome. (See 'Musculoskeletal' above.)

Renal – Rhabdomyolysis may lead to pigment-induced acute kidney injury. (See 'Renal' above.)

Neurologic – Injury to the central and peripheral nervous system can occur; manifestations can range from coma to memory dysfunction to autonomic dysfunction to mixed peripheral motor and sensory deficits (See 'Neurologic' above.)

Vascular – Vascular injury can occur and may range from coagulation of small veins to thrombosis of major arteries; signs of vascular injury can be delayed. (See 'Vascular, coagulation system, and other injuries' above.)

Other – Patients who fall or are thrown following a severe electrical exposure can sustain severe traumatic injuries; cataracts, hyphema, and vitreous hemorrhage can occur; tympanic membrane rupture is common following a lightning strike.

Prolonged cardiopulmonary resuscitation is appropriate for many patients who sustain a sudden cardiac arrest (SCA) following severe electrical injury because they are often young and outcomes are generally better than SCA from other causes. (See 'Cardiopulmonary resuscitation' above.)

A trauma evaluation and appropriate resuscitation, beginning with a rapid assessment of the airway and cardiopulmonary status, should be performed for any patient with a severe electrical exposure. Cervical spine immobilization and assessment is necessary. Coma or neurologic deficit, including alterations in mental status, should prompt brain and spine imaging. A careful secondary survey is needed once the initial resuscitation is complete. (See 'Trauma resuscitation and neurologic evaluation' above and "Initial management of trauma in adults".)

The survivor of a high-energy (>1000 V) injury should have cardiac and hemodynamic monitoring due to the high incidence of arrhythmia and autonomic dysfunction, especially if there have been arrhythmias in the field or emergency department, loss of consciousness, or if the initial ECG is abnormal. In most cases, telemetry is adequate. Patients with signs of instability (eg, recurrent arrhythmia or hypotension) require more intensive monitoring. (See 'Cardiac injury' above.)

Patients with significant electrical injuries should be monitored for the development of acute compartment syndrome, rhabdomyolysis, and acute kidney injury. Such patients often require aggressive IV fluid replacement, especially if there are signs of muscle necrosis; those with lightning injuries typically require less volume than patients with thermal burns. The approach to fluid resuscitation is similar to that used for the prevention of kidney injury from heme pigments (ie, myoglobinuria) and is discussed separately. Fluid resuscitation for patients with severe electrical injuries is comparable to that used for major crush injuries. Given the risk of hyperkalemia, IV fluids containing potassium should be avoided. (See "Prevention and treatment of heme pigment-induced acute kidney injury", section on 'Prevention' and 'Fluid resuscitation' above and 'Myoglobinuria' above.)

Skin wounds from electrical injuries are treated in a similar manner to flame or other thermal burns. Importantly, Parkland and similar formulas used for fluid resuscitation following thermal burns should not be applied to electrical injuries, since surface burns may grossly underestimate the extent of injury. (See 'Skin wounds' above.)

Electrical weapons do not cause cardiac arrhythmias or other dangerous injuries when used appropriately by law enforcement officers and exposure lasts 15 seconds or less. Prolonged observation and diagnostic testing are not necessary in such patients who are otherwise asymptomatic and alert following the exposure. The disposition of patients with an electrical exposure is discussed in the text. (See 'Electrical weapons' above and 'Disposition' above.)

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