Electrical injuries

Electrical injuries can range from something minor that needs no medical input to tetany of respiratory muscles through to cardiac arrest secondary to dysrhythmia (VF, VT or asystole). Up to 5% of burns occur secondary to electrical injuries, and this rises to 27% in developing countries.  There are two periods of peak incidence in children – under six years and adolescents aged between 13-18 years.

Significant injuries can occur even in the absence of extensive burns or other signs of external injury.

How does electricity cause harm?

• Cardiac arrest – due to the electrical effect on the heart (VF in AC, asystole in DC)
• Arrhythmia occurs in ~15%, myocardial injury is rare 
• Muscle, nerve, and tissue damage as the current passes through the body
• Rhabdomyolysis 
• Neurological injury – peripheral nerve damage, autonomic dysfunction, loss of consciousness 
• Ocular injury 
• Thermal burns from the point of contact
• Falling or being thrown following contact

What information do you need to know?

• What is the source of electricity (and is there ongoing risk to others)? 
• Was the voltage high or low (as below)?
• Where were the contact points and the length of the contact?
• Was the patient thrown from the source (suggestive of DC shock and may result in further blunt force trauma)?
• Was there any syncope?

Alternating current can result in VF cardiac arrest at lower voltages than direct current. DC is associated more with asystole. APLS provide a breakdown of the effects of an increase in current (in mA/milliamps, which is calculated using voltage and resistance*): 

• >10mA – tetanic contractions of muscles
• 50mA – tetanic contraction of respiratory muscles can lead to respiratory arrest
• 100mA – 50A – primary cardiac arrest
• >50A – prolonged respiratory and cardiac arrest 

Interestingly, a transthoracic shock (hand to hand or opposite leg) is more likely to be fatal than a vertical flow (hand to foot). However, vertical flow can result in myocardial injury secondary to coronary artery spasm.

Household supply in the UK and Australia is typically capped at 230v, so children get low-voltage injuries. This is supplied via alternating current (AC), increasing the risk of titanic contraction of skeletal muscle, leading to kids holding on to the electrical power source.

Domestic electrical injuries

Electrical injuries in the home are a significant cause of morbidity in children. The prevalence of household electrical devices and the curiosity of young children create a potentially hazardous environment.

Common Sources of Electrical Injury

1. Electrical Outlets: One of the most common sources of electrical injuries in the home. Children, especially toddlers, may insert objects into outlets, leading to shocks or burns. Outlet covers and childproofing can mitigate this risk.
2. Electrical Cords and Appliances: Damaged cords, improperly used appliances, and misuse of extension cords are frequent culprits. Ensuring cords are intact, appliances are used as intended, and excess use of extension cords is avoided can prevent injuries.
3. Water and Electricity: Bathrooms and kitchens are high-risk areas due to the presence of water. Electrical devices used near water sources can cause severe shocks. Always unplug appliances when not in use and keep them away from sinks and bathtubs.

Mechanisms of Injury

Electrical injuries can be caused by direct contact with live electrical sources or indirect contact through conductive materials. Depending on the voltage, duration of contact, and pathway of the electrical current through the body, injuries range from minor burns to severe, life-threatening conditions.

Suspected low voltage injuries (<1000v) should still be approached with an A-E assessment, but if 12 lead ECG and urinalysis are normal, it’s reasonable to discharge the patient.

If the ECG is abnormal, the patient should be managed as if exposed to a high voltage (>1000v).

An abnormal urinalysis (myoglobin or blood present) should prompt baseline bloods, looking specifically at creatine kinase and renal function. If they are symptomatic, you should watch them for at least 4–6 hours. Consider discharge if there is an absence of syncope, a normal 12-lead ECG, no secondary injuries requiring intervention, and a safe environment for discharge.

Industrial electrical injuries

While less common than domestic electrical injuries, industrial exposure to electricity can result in severe, often fatal, injuries in children. These exposures typically involve high-voltage sources such as overhead electricity pylons, train tracks, and other industrial electrical infrastructure.

Common Sources of Industrial Electrical Injury

1. Overhead Electricity Pylons: These high-voltage lines pose a significant risk, especially in rural or suburban areas where children may come into contact with pylons while playing. Climbing pylons, flying kites, and drones near power lines can lead to deadly electrical shocks.
2. Train Tracks: Railway systems often use high-voltage electricity to power trains. Trespassing on train tracks or playing near railway stations exposes children to the risk of electrocution from the electrified rails or overhead lines.
3. Industrial Sites: Construction sites, factories, and other industrial areas have numerous high-voltage sources. Unauthorized access to these sites by children can lead to severe electrical injuries.

Mechanisms of Injury

Industrial electrical injuries are typically high-voltage injuries, resulting in deep tissue damage, burns, and significant systemic effects. The high voltage can cause direct thermal injuries, as well as mechanical injuries from falls or secondary trauma.

In most paediatric cardiac arrests, the primary cause is respiratory – not so in cases of electrocution. Prolonged CPR should be considered as outcomes are generally good, even if asystole is the presenting rhythm.

Injuries can be caused by the shock itself or when children are thrown from the source, so it’s worth considering the potential for =cervical spine injuries, similar to those seen in victims of explosions or blast injuries.

Just like any major trauma, these children require a thorough primary survey looking for immediate life threats, such as airway burns or circumferential neck burns, before focussing on the more obvious burns in front of you.

Judicious fluid resuscitation is critical; patients may become volume-deplete due to fluid loss/oedema secondary to burns. Deep tissue injuries may not be visible, and as muscle breaks down, it leads to myoglobinuria, rhabdomyolysis and renal failure. Hyperkalaemia and hypocalcaemia can also occur and should be corrected during resuscitation, and if there is persistent hyperkalaemia or metabolic acidosis despite adequate fluid resuscitation, some children require emergent dialysis.

Lightning strikes

Lightning strikes are relatively uncommon but can result in catastrophic injuries or death. In the UK, lightning-related fatalities are rare, but non-fatal injuries are more frequent and can lead to long-term sequelae. Children are at risk during outdoor activities, especially in open fields, near tall structures, or during thunderstorms.

Mechanisms of Injury

Lightning strikes can affect individuals in several ways:

1. Direct Strike: The person is directly hit by the lightning.
2. Side Flash: Lightning strikes a nearby object, and some of the current jumps to the person.
3. Ground Current: Lightning strikes the ground, and the current spreads out, affecting individuals in the vicinity.
4. Conduction: Lightning travels through conductive materials such as metal fences or pipes, striking individuals in contact with these materials.

Clinical Presentation

Lightning strikes can cause a range of injuries, including burns, neurological damage, and cardiac arrest. Key clinical features include:

1. Cardiac Rhythm Disturbances: The most common presenting cardiac rhythm following a lightning strike is asystole (cardiac arrest without electrical activity). Ventricular fibrillation is less common but can also occur.
2. Keraunoparalysis: This phenomenon involves transient paralysis and sensory disturbances following a lightning strike. It is characterised by pallor, coldness, and motor paralysis in the affected limbs, often resolving within hours to days.
3. Lichtenberg Figures: These are unique, fern-like patterns on the skin caused by the passage of high-voltage electrical discharge. They are transient, typically painless, and serve as a hallmark of lightning injury.

Key Points:

Electrical injuries are common and affect every organ system.

AC and DC shocks may result in different injury patterns.

Low voltage (<1000v) injuries may be safely discharged if ECG and urinalysis are normal

High voltage injuries (>1000v) require further investigation and a period of observation with cardiac monitoring (24 hours+)

Seemingly minor surface burns do not rule out severe muscle or internal organ injury.

Voltage is the measure of electric potential difference between two points. It’s like the force that pushes electric charges through a circuit.

Think of voltage like the pressure in a water hose. If you turn the tap just a little, the water comes out with low pressure. If you turn the tap fully, the water comes out with high pressure. Similarly, higher voltage means more ‘push’ for the electric charges.

Ampage or current is the measure of the flow of electric charges. It’s like the number of electric charges passing through a point in a circuit over a certain period.

Think of current like the amount of water flowing through the hose.Iif the hose is wide, a lot of water can flow through it at once (high current). If the hose is narrow, less water flows through (low current)

References

Electrocution and Electrical Injury – Emergency Management in Children; Children’s Health Queensland Hospital and Health Service 

Baird J. Electrical Injuries. RCEM. 2019. 

Chen P, Bukhman AK. Electrical and lightning injuries. In: Walls RM, ed. Rosen’s Emergency Medicine: Concepts and Clinical Practice. 10th ed. Philadelphia, PA: Elsevier; 2023:chap 130.

Culnan, D.M., Farner, K., Bitz, G.H., Capek, K.D., Tu, Y., Jimenez, C. and Lineaweaver, W.C., 2018. Volume resuscitation in patients with high-voltage electrical injuries. Annals of Plastic Surgery, 80(3), pp.S113-S118.

Martin Samuels, Sue Wieteska. Advanced Paediatric Life Support [Internet]. Sixth. Wiley; 2016. Available from: https://onlinelibrary.wiley.com/doi/book/10.1002/9781119241225 

Part 8: Advanced Challenges in Resuscitation Section 3: Special Challenges in ECC. Resuscitation. 2000 Aug;46(1–3). 

Pittman O, Toner H. Electrical Injury Guideline, Paediatrics for Healthcare Professionals, NHS Greater Glasgow and Clyde, 2023 May

Waldmann, V., Narayanan, K., Combes, N. and Marijon, E., 2017. Electrical injury. BMJ, 357.

Spies, C. and Trohman, R.G., 2006. Narrative review: Electrocution and life-threatening electrical injuries. Annals of Internal Medicine, 145(7), pp.531-537.