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Electrical Injuries


Daniel P. Runde

, MD, MME, University of Iowa Hospitals and Clinics

Reviewed/Revised Mar 2022 | Modified Sep 2022

An electrical injury occurs when a current passes through the body, interfering with the function of an internal organ or sometimes burning tissue.

  • Often the main symptom is a skin burn, but not all serious injuries are visible.

  • Doctors check the person for abnormal heart rhythms, fractures, dislocations, and spinal cord or other injuries.

  • Abnormal heart rhythms are monitored, burns are treated, and, if the burn caused extensive internal damage, intravenous fluids and other treatments are given.

Electrical injury may result from contact with faulty electrical appliances or machinery or inadvertent contact with household wiring or electrical power lines. Getting shocked from touching an electrical outlet in the home or by a small appliance is rarely serious, but accidental exposure to high voltage causes about 300 deaths each year in the United States.

How electricity affects the body

Electrical current passing through the body generates heat, which burns and destroys tissues. Burns can affect internal tissues as well as the skin. An electrical shock can short-circuit the body’s own electrical systems, causing nerves to stop transmitting impulses or to transmit impulses erratically. Abnormal impulse transmission can affect the

The severity of the injury ranges from minor to fatal and is determined by the following factors:

  • Intensity of the current

  • Type of current

  • Pathway of the current through the body

  • Duration of exposure to the current

  • Electrical resistance to the current

Intensity of the current

The intensity of the current is measured in volts and amperes. Ordinary household current in the United States is 110 to 220 volts. In many other countries, standard household current is 220 volts. A standard electrical outlet in the US is 110 volts, and 220 volts is used for large appliances such as dryers or refrigerators. Anything over 500 volts is considered high voltage. High voltage can jump (arc) through the air anywhere from an inch up to several feet, depending on the voltage. Thus, a person may be injured simply by coming too close to a high-voltage line. High voltage causes more severe injuries than low voltage and is more likely to cause internal damage.

Type of current

Electrical current is categorized as direct current (DC) or alternating current (AC). Direct current, such as current generated by batteries, flows in the same direction constantly. Alternating current, such as current available through household wall sockets connected to the power grid, changes direction 50 to 60 times per second.

Alternating current is more dangerous than direct current. Direct current tends to cause a single muscle contraction often strong enough to force people away from the current’s source. Alternating current causes a continuing muscle contraction, often preventing people from releasing their grip on the current’s source. As a result, exposure may be prolonged. Even a small amount of alternating current—barely enough to be felt as a mild shock—may cause the grip to freeze. Slightly more alternating current can cause the chest muscles to contract, making breathing impossible. Even more current can cause deadly abnormal heart rhythms Overview of Abnormal Heart Rhythms Abnormal heart rhythms (arrhythmias) are sequences of heartbeats that are irregular, too fast, too slow, or conducted via an abnormal electrical pathway through the heart. Heart disorders are... read more Overview of Abnormal Heart Rhythms (arrhythmias).

Pathway of the current

The path that the electricity takes through the body tends to determine which tissues are affected. Because alternating current continually reverses direction, the commonly used terms “entry” and “exit” are inappropriate. The terms “source” and “ground” are more precise. The most common source point for electricity is the hand, and the second most common is the head. The most common ground point is the foot. A current that travels from arm to arm or from arm to leg may go through the heart and is much more dangerous than a current that travels between a leg and the ground. A current that travels through the head may affect the brain.

Duration of exposure

In general, the longer the person is exposed to the current, the worse the injury.

Resistance to the current

Resistance is the ability to impede the flow of electricity. Most of the body’s resistance is concentrated in the skin. The thicker the skin is, the greater its resistance. A thick, callused palm or sole, for example, is much more resistant to electrical current than an area of thin skin, such as an inner arm. The skin’s resistance decreases when broken (for example, punctured or scraped) or when wet. If skin resistance is high, more of the damage is local, often causing only skin burns Burns . If skin resistance is low, more of the damage affects the internal organs. Thus, the damage is mostly internal if people who are wet come in contact with electrical current, for example, when a hair dryer falls into a bathtub or people step in a puddle that is in contact with a downed electrical line.

Symptoms of Electrical Injuries

Often, the main symptom of an electrical injury is a skin burn, although not all electrical injuries cause external damage. High-voltage injuries may cause massive internal burns. If muscle damage is extensive, a limb may swell so much that its arteries become compressed (compartment syndrome Compartment Syndrome Compartment syndrome is increased pressure in the space around certain muscles. It occurs when injured muscles swell so much that they cut off their blood supply. Pain in the injured limb increases... read more ), cutting off blood supply to the limb. If a current travels close to the eyes, it may lead to cataracts Cataract A cataract is a clouding (opacity) of the lens of the eye that causes a progressive, painless loss of vision. Vision may be blurred, contrast may be lost, and halos may be visible around lights... read more Cataract . Cataracts can develop within days of the injury or years later. If large amounts of muscle are damaged (a disorder called rhabdomyolysis Rhabdomyolysis Rhabdomyolysis occurs when muscle fibers damaged by disease, injury, or toxic substances break down and release their contents into the bloodstream. Severe disease can cause acute kidney injury... read more ), a chemical substance, myoglobin, is released into the blood. The myoglobin can damage the kidneys.

Young children who bite or suck on electrical cords can burn their mouth and lips. These burns may cause facial deformities and growth problems of the teeth, jaw, and face. An added danger is that severe bleeding from an artery in the lip may occur when the scab falls off, usually 5 to 10 days after the injury.

A minor shock may cause muscle pain and may trigger mild muscle contractions or startle people, causing a fall. Severe shocks can cause abnormal heart rhythms Overview of Abnormal Heart Rhythms Abnormal heart rhythms (arrhythmias) are sequences of heartbeats that are irregular, too fast, too slow, or conducted via an abnormal electrical pathway through the heart. Heart disorders are... read more Overview of Abnormal Heart Rhythms , ranging from inconsequential to immediately fatal. Severe shocks can also trigger powerful muscle contractions sufficient to throw people to the ground or to cause joint dislocations, bone fractures, and other blunt injuries.

Diagnosis of Electrical Injuries

  • A doctor's evaluation

Doctors check people for burns, fractures, dislocations, and spinal cord or other injuries.

Most people who have no symptoms, have no known heart disorders, have had only brief exposure to low levels of current, and are not pregnant do not require testing or monitoring. An electrocardiogram Electrocardiography Electrocardiography (ECG) is a quick, simple, painless medical test that measures the heart’s electrical impulses. During an ECG, the heart's electrical impulses are measured, amplified, and... read more Electrocardiography (ECG) is done to monitor the heartbeat in some people. For some people, blood and urine tests may be needed. If people are unconscious, imaging tests Overview of Imaging Tests Imaging tests provide a picture of the body’s interior—of the whole body or part of it. Imaging helps doctors diagnose a disorder, determine how severe the disorder is, and monitor people after... read more such as computed tomography (CT) or magnetic resonance imaging (MRI) of the brain may be needed.

Prevention of Electrical Injuries

Education about and respect for electricity are essential. Making sure that all electrical devices are properly designed, installed, and maintained helps prevent electrical injuries at home and work. Electrical wiring should be installed and serviced by properly trained people. Outlet guards reduce risk in homes with infants or young children.

Any electrical device that touches or may be touched by the body should be properly grounded. Three-pronged outlets are safest. Cutting off the lower (ground) prong of a power cord with three prongs (so that it will fit older two-pronged plugs) is dangerous and increases the chances of electrical injury. Circuit breakers that interrupt (trip) circuits when current as low as 5 milliamperes leaks are advisable in areas that get wet, such as kitchens and bathrooms and outdoors.

To avoid injury from current that jumps (arcing injury), poles and ladders should not be used near high-voltage power lines.

Treatment of Electrical Injuries

  • Cardiopulmonary resuscitation

  • Burn treatment

First the person must be separated from the current’s source. The safest way to do so is to shut off the current—for example, by throwing a circuit breaker or switch or by disconnecting the device from an electrical outlet. No one should touch the person until the current has been shut off.

High-voltage and low-voltage lines are difficult to distinguish, especially outdoors. Shutting off current to high-voltage lines is done by the local power company. Many well-meaning rescuers have been injured by electricity when trying to free a person.

Once the person can be safely touched, the rescuer should check to see if the person is breathing and has a pulse. If the person is not breathing and has no pulse, cardiopulmonary resuscitation First-Aid Treatment for Cardiac Arrest Cardiac arrest is when the heart stops pumping blood and oxygen to the brain and other organs and tissues. Sometimes a person can be revived after cardiac arrest, particularly if treatment is... read more First-Aid Treatment for Cardiac Arrest (CPR) should be started immediately. Emergency medical assistance should be called for any person who has more than a minor injury. Because the extent of an electrical burn may be deceptive, medical assistance should be sought if any doubt exists regarding severity.

People with rhabdomyolysis are usually given large amounts of fluids intravenously.

If the injury is painful, people are given analgesics.

Skin burns Burns are treated with burn cream and sterile dressings. A person with only minor skin burns can usually be treated at home. If the injury is more severe, the person is admitted to the hospital, ideally a burn center. The person is kept in the hospital for 6 to 12 hours if any of the following exists:

Young children who bite or suck on electrical cords should be referred to a children’s orthodontist, an oral surgeon, or a surgeon who is experienced in the care of these injuries.

More Information

The following are some English-language resources that may be useful. Please note that THE MANUAL is not responsible for the content of these resources.

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