Chemical and Electrical Burns

Chemical burns: clinical features and diagnosis

Massive chemical injuries at an early stage can cause shock. Locally, such burns are usually limited, have well-defined margins, and characteristic traces in the form of splash spots or streaks of flowing liquid.

The color of the scab helps determine the damaging agent (in acid burns):

• Sulfuric acid — scab is grey, dark brown, or black.
• Nitric acid — scab is yellow.
• Hydrochloric acid — scab is grey-yellow.
• Acetic acid — scab is greenish.

First aid for chemical injury

The main rule is to remove the aggressive substance as quickly as possible. This is usually achieved by rinsing the wound under running water:

1. If assistance is started immediately — wash for 10–15 minutes.
2. If started late — 30–40 minutes.
3. Hydrofluoric acid requires continuous irrigation for 2–3 hours (until the odor disappears or litmus paper shows a neutral reaction).

Important exception! Quicklime burns must not be washed with water. Interaction with water triggers an exothermic reaction, leading to an additional thermal burn. Lime must be removed only mechanically.

After removing the substance, a dry aseptic dressing is applied, and further treatment is carried out according to the rules of thermal burn therapy.

Mechanisms and specifics of electrical burns

Electric current exerts electrochemical and general biological effects. The electrochemical action leads to changes in ion concentration: intracellular proteins turn into a gel, forming coagulation necrosis. Simultaneously, aggregation of formed blood elements occurs, causing microvascular thrombosis and secondary necrosis.

The biological effect manifests as spasmodic muscle contraction and myocardial conduction disturbances. High-voltage electric shock can cause instant death from ventricular fibrillation or respiratory arrest. It is important to remember that cardiac arrest can occur not only at the time of trauma, but also days later.

Local features of electrical burns:

• Painlessnes due to complete destruction of nerve endings.
• Dry necrosis, which sloughs off very slowly.
• Progression of damage to muscles and bones due to vascular thrombosis (risk of gangrene).
• Skin damage is not continuous in nature (unlike thermal burns).
• Foci of necrosis may lie beneath visually undamaged epidermis.

Specific changes and treatment of electrical injury

Histologically, during electrical injury, the basal layers of the skin curl, forming cavities — "honeycombs". Upon contact with metal, tissue metallization occurs: copper gives a yellow-brown color, iron — greyish. In bones, due to electrolysis and the dissolution of calcium and phosphorus salts, "pearls" are formed.

High-voltage burns are always deep (IIIb–IV degrees) and have current marks (entry and exit). They are characterized by the spread phenomenon: tissue destruction in the depth is significantly wider than the visible skin defect (funnel-shaped lesion).

Surgical treatment:

• Necrectomy is performed in several stages due to the depth and slow sloughing of tissues.
• Osteonecrectomy is performed in the early stages.
• Amputation is indicated early in cases of limb charring to prevent hemorrhage, sepsis, and renal failure.
• Plastic surgery is postponed to a later period.

In general therapy, if acute renal failure (anuria) develops, hemodialysis is mandatory.

Class and exam questions

What else to study on this topic

• Histological picture of the skin in electrical injury ("honeycombs")
• Pathogenesis of progressive necrosis in vascular thrombosis
• Features of the electric arc effect
• Indications for hemodialysis in acute renal failure in burn patients
• Technique of staged necrectomy in deep lesions

Other topics in "CHAPTER 10. GENERAL ISSUES IN TRAUMATOLOGY"

Prepared by WhiteCoat Pro faculty in accordance with the medical school curriculum. For educational purposes only.