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Summary
- Electric shock is when an electrical current passes through the body.
- Electric shock can cause injury ranging from minor burns to massive tissue damage, and may be fatal.
- The best way to break contact between the person being shocked and the power source is to shut off the current at the main fuse box.
- Prevention entails proper design, installation and maintenance of electrical devices, as well as respect for the dangers of electricity.
Cause
Electric shock occurs when a person comes into contact with an electrical power source, resulting in a current passing through the body. The source could be a defective household appliance, electrical wire or lightning.
Electric shock can cause effects ranging from a brief tingling sensation that is unpleasant but otherwise harmless, to massive tissue damage. Some shocks are instantly fatal.
Symptoms and signs
The effects and signs and symptoms of electrical injuries may include the following:
- An electric shock can startle you and cause you to fall or be thrown down.
- It may cause severe, rigid contractions of the muscles which in turn may result in fractures, dislocations and loss of consciousness.
- The respiratory system may be paralysed and the heart may beat irregularly or even stop beating.
- Sharply demarcated electrical burns may be present on the skin and extend into deeper tissue.
- High voltage may cause tissue death between the entry and exit point of the current. Massive swelling of the tissues may follow as the blood in the veins coagulates and the muscles swell.
- Low blood pressure, fluid and electrolyte disturbances and the release of the protein myoglobin can cause kidney failure.
- Bathtub accident victims, who suffer electric shock while in the water, may show no burns but suffer cardiac arrest.
- Lightning rarely leaves entry or exit wounds and seldom causes muscle damage or myoglobin release. Coma or other evidence of damage to the nervous system may occur, but usually resolves within hours or days. Death is usually due to failure of both the respiratory and cardiac systems.
First aid
- Don't approach the person who has been electrocuted until you're certain the area is safe.
- Break contact between the person and the current source as quickly as possible: the best way to do this is to shut off the current at the main fuse box. Don't use the switch on the appliance. It is not recommended to use a wooden stick or similar to separate the person from the appliance: some power sources can arc up to 8 metres.
- A person who has been struck by lightning poses no danger to the rescuer.
- Check the ABCs (airway, breathing, circulation), start CPR if necessary and call an ambulance.
- Check for signs of shock (the life-threatening condition which occurs when blood flow is too low to serve the vital organs. Major burns cause loss of body fluids, which can lead to shock.)
- With high voltages, the person may have been thrown into the air and may have sustained back, head or neck injuries. Internal body damage is not always obvious.
- Cover any burnt area with a sterile gauze bandage or a clean cloth.
Prevention
Prevention of electrical injuries entails proper design, installation and maintenance of all electrical devices. Education and compliance with instructions as to the use of electric appliances, as well as common sense and respect in dealing with electricity, are essential.
Any electrical device that touches or may be touched by the body and has life-threatening potential should be properly earthed and incorporated in circuits containing fail-safe equipment. Ground-fault circuit breakers, which trip at current leakage to ground levels of as low as 5mA, are excellent safety devices and are readily available.
Updated July 2009
