Electric shock injuries

Definition

Electric shock injuries are caused by lightning or electric current passing through the body. In infants, electric shock injuries occur most often when they put metal objects in their mouths.

Description

Electric current can be described as the flow of microscopic particles called electrons through wires and electrical appliances. Materials like metal and water through which electric current (electricity) travels easily are called conducting materials or conductors. The body is an excellent conductor, and electric current from any source passing through the body produces electric shock injuries.

The severity of electric shock injuries depends on the current's voltage, the amount of current (amperage), the type of current (direct or alternating), the body's resistance to the current, the current's path through the body, and the length of time the body remains in contact with the current. The interplay of these factors can produce effects ranging from a mild tingling to instant death. How electric shocks affect the skin depends on the skin's resistance to current, which in turn depends on the wetness, thickness, and cleanliness of the skin. Thin or wet skin is much less resistant than thick or dry skin. When the skin's resistance to current is low, the current may cause little or no skin damage but severely burn internal organs and tissues. By contrast, high skin resistance can produce severe skin burns but prevent the current from entering the body.

The nervous system (brain, spinal cord, and nerves) is very sensitive to electric shock injury, and neurological problems are the most common consequences suffered by electric shock victims. Neurological damage can be minor and clear up on its own or with medical treatment or can be severe and permanent. Damage to the respiratory and cardiovascular systems is highest at time of injury. Electric shocks can paralyze the respiratory system or disrupt heart action, causing instant death. Also at risk are the smaller veins and arteries, which can develop blood clots. Damage to the smaller vessels is often followed by amputation after high-voltage injuries. Many other injuries are possible after an electric shock, including cataracts, kidney failure, and destruction of muscle tissue. The victim may also suffer a fall or an electric arc may set clothing or nearby flammable substances on fire. Strong shocks are often accompanied by violent muscle spasms that can break and dislocate bones.

Demographics

Electric shocks are responsible for about 1,000 deaths in the United States each year, or about 1 percent of all accidental deaths. Children are not often seriously injured by electricity, but they are prone to electric shock by the low voltage (110–220 volts) of typical household current. In children aged 12 years and younger, household appliance electrical cords and extension cords are reported to cause more than 63 percent of injuries. Wall outlets are responsible for 15 percent of electric injuries.

Causes and symptoms

Electric shocks are caused by the passage of electric current through the body. They are caused in infants and young children by their playing with electrical appliances or cords and in older children by mischievous exploration of electrical systems or use of faulty electrical appliances or tools.

A child who has suffered an electric shock may have very little external injury or may have obvious severe burns. Burns are usually most severe at the points of contact with the electrical source. The hands, heels, and head are common points of contact. Other injuries are also possible if the child has been thrown clear of the electrical source by forceful muscular contractions. The child may have internal injuries especially if he or she is experiencing any shortness of breath, chest pain , or abdominal pain. In children, the typical electrical mouth burn from biting an electric cord appears as a burn on the lip. The area has a red or dark, charred appearance.

When to call the doctor

A person shocked by high voltage (500 volts or more) should be evaluated in the emergency department of a hospital or clinic. Any person present at the scene of the accident should immediately call 911.

Brief low-voltage shocks (110–220 volts or less) that do not result in any symptoms or burns of the skin do not require care. However, following a low-voltage shock, parents should consult their healthcare provider if the child has any noticeable burn to the skin, any numbness , tingling, or vision, hearing, or speech problems, no matter how mild. A doctor should also always evaluate electric cord burns to the mouth of a child.

Diagnosis

Diagnosis relies on the information gathered about the circumstances of the electric shock, a thorough physical examination, and monitoring of cardiovascular and kidney activity. The physician's primary concern is to determine if significant unseen injury exists. Injury may occur to muscles, the heart, or the brain from the electricity or to any bones or other organs from being thrown from the electric source. Tests may include any of the following:

• electrocardiogram (ECG) to check the heart
• complete blood count (CBC)
• urine test for muscle enzymes, to screen for muscle injury
• x rays or magnetic resonance imaging (MRI) to look for fractures or dislocations, both of which may be caused by electrocution
• CT scan for internal injuries

Treatment

When a severe electric shock injury happens at home, the main power should immediately be shut off. If that cannot be done, and current is still flowing through the child, the alternative is to stand on a dry, nonconducting surface such as a folded newspaper, flattened cardboard carton, or plastic or rubber mat and use a nonconducting object such as a wooden broomstick (never a damp or metallic object) to push the child away from the source of the current. The victim and the source of the current must not be touched while the current is still flowing, for doing so can electrocute the rescuer. Emergency medical help should be summoned as quickly as possible. People who are trained to perform cardiopulmonary resuscitation (CPR) should, if appropriate, begin first aid while waiting for emergency medical help to arrive.

At the clinic or hospital, treatment depends on the severity of the burns and/or the nature of other injuries found. Minor burns are usually treated with topical antibiotic ointment and dressings. More severe burns may require surgery to clean the wounds or even to perform skin grafting. Severe burns on the arms, legs, or hands may require surgery to remove damaged muscle or even amputation.

Prognosis

Recovery from electric shock depends on the nature and severity of the injuries. The percentage of the body surface area burned is the most important factor affecting prognosis. Electric shocks cause death in 3–15 percent of cases, with infection being the most common cause of death in people hospitalized following electrical injury. Electrical damage to the brain may result in a permanent seizure disorder , depression, anxiety , or other personality changes. Injuries from household appliances and other low-voltage sources are less likely to produce extreme damage.

Prevention

Parents and other adults need to be aware of possible electric dangers in the home. Damaged electric appliances, wiring, cords, and plugs should be repaired, replaced or discarded. Hair dryers, radios, and other electric appliances should never be used in the bathroom or where they may accidentally come in contact with water. Young children need to be kept away from electrical appliances and should be taught about the dangers of electricity as early as possible. They should not be allowed to play with any electrical cord. Electric outlets also require safety covers in homes with young children. In children older than 12 years, most electrical injuries result from exploring and playing around high-power systems. Teenagers should accordingly be warned not to climb on power towers, play near transformer systems, or explore electrified train rails or other electrical systems.

KEY TERMS

Computed tomography (CT) —An imaging technique in which cross-sectional x rays of the body are compiled to create a three-dimensional image of the body's internal structures; also called computed axial tomography.

Conducting materials —Materials that conduct electricity, materials through which electric current travels easily. Examples are metals and water.

Electric current —The rate of flow of electric charge, measured in amperes. Electric current can also be described as the flow of microscopic particles called electrons flowing through wires and electronic components and appliances.

Electrical resistance —Resistance to the flow of electrical current.

Magnetic resonance imaging (MRI) —An imaging technique that uses a large circular magnet and radio waves to generate signals from atoms in the body. These signals are used to construct detailed images of internal body structures and organs, including the brain.

Non-conducting materials —Also called insulators, materials through which electric current does not propagate. Examples are ceramics, rubber, wood.

Skin grafting —A surgical procedure by which skin or a skin substitute is placed over a burn or nonhealing wound to permanently replace damaged or missing skin or to provide a temporary wound covering.

See also Computed tomography.

Resources

BOOKS

Cadick, John, et al. Electrical Safety Handbook, 2nd ed. New York: McGraw-Hill, 2001.

Kovacic, Thomas, M., et al. An Illustrated Guide to Electrical Safety. Des Plaines, IL: American Society of Safety Engineers, 2003.

Marne, David. McGraw-Hill's National Electrical Safety Code Handbook. New York: McGraw-Hill Professional Publishing, 2002.

PERIODICALS

Koumbourlis, A. C. "Electrical Injuries." Critical Care in Medicine 11 Suppl. (November 2002): S424–30.

Marinez, J. A., and T. Nguyen. "Electrical Injuries." South Medical Journal 93, no. 12 (December 2000): 1165–68.

ORGANIZATIONS

Home Safety Council. 1725 Eye Street NW, Suite 300, Washington, DC 20006. Web site: <www.homesafetycouncil.org>.

National Center for Injury Prevention and Control (NCIPC). Mailstop K65, 4770 Buford Highway NE, Atlanta, GA 30341–3724. Web site: <www.cdc.gov/ncipc/>

WEB SITES

"First Aid for Electric Shock." HealthWorld Online. Available online at <www.healthy.net/scr/article.asp?id=1490> (accessed November 25, 2004).

Price, Timothy G. "Electric Shock." emedicine.com, August 10, 2004. Available online at <www.emedicine.com/aaem/topic177.htm> (accessed November 25, 2004).

Monique Laberge, Ph.D.

Electric Shock Injuries

Definition

Electric shock injuries are caused by lightning or electric current from a mechanical source passing through the body.

Description

Electric shocks are responsible for about 1,000 deaths in the United States each year, or about 1% of all accidental deaths.

Causes and symptoms

The severity of injury depends on the current's pressure (voltage), the amount of current (amperage), the type of current (direct vs. alternating), the body's resistance to the current, the current's path through the body, and how long the body remains in contact with the current. The interplay of these factors can produce effects ranging from barely noticeable tingling to instant death ; every part of the body is vulnerable. Although the severity of injury is determined primarily by the voltage, low voltage can be just as dangerous as high voltage under the right circumstances. People have been killed by shocks of just 50 volts.

How electric shocks affect the skin is determined by the skin's resistance, which in turn is dependent upon the wetness, thickness, and cleanliness of the skin. Thin or wet skin is much less resistant than thick or dry skin. When skin resistance is low, the current may cause little or no skin damage but severely burn internal organs and tissues. Conversely, high skin resistance can produce severe skin burns but prevent the current from entering the body.

The nervous system (the brain, spinal cord, and nerves) is particularly vulnerable to injury. In fact, neurological problems are the most common kind of nonlethal harm suffered by electric shock victims. Some neurological damage is minor and clears up on its own or with medical treatment, but some is severe and permanent. Neurological problems may be apparent immediately after the accident, or gradually develop over a period of up to three years.

Damage to the respiratory and cardiovascular systems is most acute at the moment of injury. Electric shocks can paralyze the respiratory system or disrupt heart action, causing instant death. Also at risk are the smaller veins and arteries, which dissipate heat less easily than the larger blood vessels and can develop blood clots. Damage to the smaller vessels is probably one reason why amputation is often required following high-voltage injuries.

Many other sorts of injuries are possible after an electric shock, including cataracts, kidney failure, and substantial destruction of muscle tissue. The victim may suffer a fall or be hit by debris from exploding equipment. An electric arc may set clothing or nearby flammable substances on fire. Strong shocks are often accompanied by violent muscle spasms that can break and dislocate bones. These spasms can also freeze the victim in place and prevent him or her from breaking away from the source of the current.

Diagnosis

Diagnosis relies on gathering information about the circumstances of the accident, a thorough physical examination, and monitoring of cardiovascular and kidney activity. The victim's neurological condition can fluctuate rapidly and requires close observation. A computed tomography scan (CT scan) or magnetic resonance imaging (MRI) may be necessary to check for brain injury.

Treatment

When an electric shock accident happens at home or in the workplace, the main power should immediately be shut off. If that cannot be done, and current is still flowing through the victim, the alternative is to stand on a dry, nonconducting surface such as a folded newspaper, flattened cardboard carton, or plastic or rubber mat and use a nonconducting object such as a wooden broomstick (never a damp or metallic object) to push the victim away from the source of the current. The victim and the source of the current must not be touched while the current is still flowing, for this can electrocute the rescuer. Emergency medical help should be summoned as quickly as possible. People who are trained to perform cardiopulmonary resuscitation (CPR) should, if appropriate, begin first aid while waiting for emergency medical help to arrive.

Burn victims usually require treatment at a burn center. Fluid replacement therapy is necessary to restore lost fluids and electrolytes. Severely injured tissue is repaired surgically, which can involve skin grafting or amputation. Antibiotics and antibacterial creams are used to prevent infection. Victims may also require treatment for kidney failure. Following surgery, physical therapy to facilitate recovery, and psychological counseling to cope with disfigurement, may be necessary.

Prognosis

Electric shocks cause death in 3-15% of cases. Many survivors require amputation or are disfigured by their burns. Injuries from household appliances and other low-voltage sources are less likely to produce extreme damage.

Prevention

Parents and other adults need to be alert to possible electric dangers in the home. Damaged electric appliances, wiring, cords, and plugs should be repaired or replaced. Electrical repairs should be attempted only by people with the proper training. Hair dryers, radios, and other electric appliances should never be used in the bathroom or anywhere else they might accidentally come in contact with water. Young children need to be kept away from electric appliances and should be taught about the dangers of electricity as soon as they are old enough. Electric outlets require safety covers in homes with young children.

During thunderstorms, people should go indoors immediately, even if no rain is falling, and boaters should return to shore as rapidly as possible. People who cannot reach indoor shelter should move away from metallic objects such as golf clubs and fishing rods and lie down in low-ground areas. Standing or lying under or next to tall or metallic structures is unsafe. An automobile is appropriate cover, as long as the radio is off. Telephones, computers, hair dryers, and other appliances that can act as conduits for lightning should not be used during thunderstorms.

Resources

BOOKS

Dimick, Alan R. "Electrical Injuries." In Harrison's Principles of Internal Medicine, edited by Anthony S. Fauci, et al. New York: McGraw-Hill, 1997.

KEY TERMS

Antibiotics— Substances used against microorganisms that cause infection.

Cataract— Clouding of the lens of the eye or its capsule (surrounding membrane).

Computed tomography scan (CT scan)— A process that uses x rays to create three-dimensional images of structures inside the body.

Electrolytes— Substances that conduct electric current within the body and are essential for sustaining life.

Magnetic resonance imaging (MRI)— The use of electromagnetic energy to create images of structures inside the body.

Skin grafting— A technique in which a piece of healthy skin from the patient's body (or a donor's) is used to cover another part of the patient's body that has lost its skin.