Clinical Features of Injury

The clinical features of electrical injury are listed below:

Cardiac dysrhythmias

Asystole (DC) and VF / VT (AC) are the most sinister cardiac dysrhythmias. Numerous other dysrhythmias may occur. These include atrial fibrillation and atrial tachycardia, junctional rhythms, SVT, 1st and 2nd degree heart block and premature ventricular beats. ST segment abnormalities may be evident and usually resolve spontaneously. Coronary artery spasm and thrombosis can cause myocardial ischaemia and infarction.

Post mortem studies demonstrate a variety of anatomical cardiac changes following electrocution including widespread focal necrosis of the myocardium and specialised tissue such as the atrioventricular and sinoatrial nodes.

Respiratory system

Passage of current through the lungs can cause pulmonary oedema, pneumothorax and respiratory failure. Tetany of the diaphragm and intercostal muscles during exposure to the current can cause apnoea and hypoxia.

Cutaneous burns

These can help to predict the direction in which the current has passed, and so determine which underlying structures may be damaged. They can be of varying degrees of severity from first degree through to third degree. The cutaneous element of an electrical burn often correlates poorly with the amount of underlying damage that has been sustained.

Peripheral neurological features

Direct injury can occur to the peripheral nerves causing peripheral neuropathy and loss of function.

Central nervous system (CNS) features

Many different effects, including seizures, hemiplegia, cognitive impairment, and spinal syndromes with limb paralysis.

Musculoskeletal features

Burns to muscle can cause rhabdomyolysis leading to acute renal failure, and muscle contractures and deformity. Compartment syndrome can occur. There may also be injuries sustained if a patient has been thrown backwards following an electric shock.

Ocular features

Passage of current through or adjacent to the eye may produce burns to the cornea, sclera or deeper structures. Cataract formation is a delayed consequence of lens involvement.

Vascular injuries

Involvement of blood vessels in the current pathway can produce vascular spasm and thrombosis with potential distal ischaemia. Delayed aneurysm formation may result from damage to the vessel wall.

Intra oral burns

Intra oral burns are more common in young children. The characteristic patient is the toddler who explores domestic electrical appliances or cables by placing them in his or her mouth. Current conduction may be aided by electrolyte rich saliva.

Delayed haemorrhage is a recognised feature of intra oral electrical burns. Haemostasis may initially appear satisfactory, but as temporary vasospasm induced by the current resolves, severe haemorrhage may result. Contraction of scar tissue has the potential to make intra oral burns particularly disfiguring.

Effects upon the foetus

Amniotic fluid readily conducts electrical current. If the gravid uterus is involved in the electrical pathway the effects on the foetus may be devastating. Maternal cardiac arrest and dysrhythmias also compromise uteroplacental blood flow.