Specific tissue damage
The passage of an electric charge directly through the body causes four interrelated types of reactions:
- Biological effect: manifests as acute irritation of the nervous system and musculature. Life-threatening conditions occur: vocal cord spasm, respiratory failure, and ventricular fibrillation. Hormones (especially catecholamines) are massively released into the blood, causing a spike in blood pressure.
- Electrochemical effect: charged ions accumulate at different poles. Coagulation necrosis forms near the anode (+), and liquefaction necrosis near the cathode (-). Impregnation (soaking) of the skin with microscopic particles of the conductor metal is also possible.
- Thermal effect: electrical energy is transformed into thermal energy. Tissues with low specific electrical conductivity (skin, bone tissue) heat up the most. Severe burns occur, up to charring. The higher the voltage, the more intense the heating.
- Mechanical effect: accompanied by massive tissue tearing and delamination due to the instantaneous release of heat and mechanical energy. In high-voltage electric shocks, the victim can be thrown a long distance, and limb avulsions are even possible.
Systemic hemodynamic disorders
The cardiovascular system suffers first. Pathological changes occur both due to direct mechanical trauma or hypoxia and as a result of the cardiotoxic effect of a high concentration of thyroid hormones and catecholamines.
Manifestations include:
- Significant tachycardia and various types of arrhythmias (from bradycardia to fibrillation).
- A sharp decrease in cardiac and stroke output.
- Global microcirculation and central hemodynamics disorders.
- Systemic venous hyperemia and blood stasis in the capillary bed.
Nonspecific effect of current
This type of injury is associated with the conversion of electrical energy in external sources, meaning the current does not pass directly through the human body. These include:
- Light radiation: a powerful electric arc flash causes eye damage—electroophthalmia and corneal burns.
- Acoustic and baric impact: sound and shock wave can provoke rupture of the tympanic membranes and severe trauma to the auditory apparatus.
- Secondary injuries: thermal burns from ignited clothing, as well as mechanical injuries from falls from height (dislocations, compression bone fractures).
Severity grades of electrical injury
The clinical picture largely depends on the resistance of the integument. Dry skin acts as a dielectric with a resistance of up to 2,000,000 ohms. When moistened, this figure drops to 1,000 ohms or lower, making the shock lethal.
There are four severity grades of systemic electrical injury:
- Grade I: convulsive muscle contractions, the patient is conscious.
- Grade II: muscle cramps accompanied by loss of consciousness.
- Grade III: profound loss of consciousness, accompanied by severe cardiac activity disorders.
- Grade IV: onset of clinical death.
Clinical nuance: paradoxically, the formation of a deep burn with charring can reduce the severity of the systemic lesion. Charred dry tissues begin to act as an insulator, preventing the further penetration of current deep into the body.
Principles of evacuation and specialized care
The management tactics for patients with electrical burns depend on the predicted recovery time. If complete recovery takes up to 2–3 months, the victims remain on-site. More severe patients are subject to evacuation to rear medical facilities.
Specialized medical care is aimed at solving several tasks:
- Combating toxemia (poisoning by breakdown products) and wound exhaustion.
- Plastic closure of formed skin defects.
- Treatment of early secondary complications.
- Surgical elimination of aesthetic defects, as well as cicatricial deformities and contractures limiting joint mobility.
To remember the electrochemical effect, use the A-Coag, C-Liq rule: Coagulation necrosis occurs at the Anode, and Liquefaction necrosis at the Cathode.
Class and exam questions
Why does wet skin significantly increase the risk of death from electric shock?
Moisture catastrophically reduces the electrical resistance of the skin from 2,000,000 ohms to 1,000 ohms or less. Under such conditions, a current significantly exceeding the lethal threshold of 0.1 A passes unhindered through the body.
Can a severe electrical burn paradoxically save a life?
Yes, during the formation of a dense scab and tissue charring. Dead charred areas have high resistance and begin to function as a dielectric, reducing the intensity of systemic damage to internal organs.
What are the main mechanisms of electrical injury?
Injury occurs not only upon direct contact with a bare wire, but also without direct contact: as a result of arc breakdown (when approaching a high-voltage line) or a short circuit near a person.
What else to study on this topic
- Pathogenesis and features of injuries caused by atmospheric electricity (lightning).
- Mechanisms of the cardiotoxic effect of catecholamines in electrical injury.
- Surgical tactics for eliminating cicatricial deformities and contractures after electrical burns.
- Causes of toxemia and wound exhaustion in massive burns.
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