ELECTRICAL INJURIES

INTRODUCTION It can be occupational hazard, accident, lightning and rarely homicide. Electrons cause depolarization of muscles and nerves. Degree of conductance in descending order – nerves, blood vessels, muscles, skin, fat and bone.

PATHOPHYSIOLOGY Epidermis gives resistance to low voltage current. But, if it is wet, then the whole body will be like a conductor causing more damage without entry and exit points. Abnormal electrical rhythms in the heart and brain if the voltage and duration are more. Bone gives more resistance. It dissipates heat even after cessation of current flow. Myonecrosis, myoglobinuria

ENTRY WOUND

TYPES Low voltage (<600 watts) High voltage (>600 watts) Lightning Direct current

LOW VOLTAGE AC It causes involuntary continuous muscle contractions (tetany). Patient will have prolonged contact with current. Typically occurs in young children who bite into electrical appliances. Circumoral burns are common. That can cause delayed bleeding after 2-3 days. It can cause thermal or flash burns

ORAL COMMISSURE BURN

HIGH VOLTAGE AC More than 600 watts Thermal or flash burns are rare. Arcing burns are common. It is present as dry parchment area with rim of congestion. It indicates more internal injury. Direct contact burns does not cause singeing of the hair whereas flash burns cause. Entry and exit wounds are not prominent. If passes through skull, it can cause amnesia and loss of consciousness Prolonged contact will cause cardiac arrhythmias (VF).

FLASH BURNS

LIGHTNING Arc or flash burns are common. Step voltage is an important phenomenon. Lichtenberg figure – christmas tree pattern. Look for burns in unusual sites like undersurface of the scrotum and penis Otoscopic examination: Perforation of ear drum and hemorrhage behind the ear drum Rarely causes myonecrosis and myoglobinuria

LICHTENBERG FIGURE

DIRECT CURRENT Direct current shock usually occurs in younger risk taking individuals Usually observed in electrical train circuit It causes single muscle contraction and throw the victim to cause blunt injury. It can also cause cardiac arrhythmias. Myonecrosis and electrical burns

PROGNOSTIC FACTORS Depends on type, duration, voltage and resistance by body. High voltage and lightning cause more morbidity. Low voltage current has high mortality rate.

INVESTIGATIONS Routine CBC, RFT, Electrolytes Urine pH, specific gravity, myoglobin CPK, LDH Serum myoglobin levels ECG ABG Imaging studies to rule out any injury EEG in any unconscious victim

MANAGEMENT Remove the victim from the circuit ABC Look for any neck injury and stabilize the neck Adequate hydration either with NS or RL Alkalinize the urine for the removal of myoglobin. Cardiac monitoring for rhythm alteration Fasciotomy in some cases of high voltage burns