Keywords
Brain imaging - electrical burn - electrical injury
Introduction
Electrical injuries are increasing worldwide and occur commonly in children and young adults. The incidents among utility or construction workers tend to be high-voltage accidents, while among children low-voltage exposures are commoner. A smaller group includes electrical injury due to lightning strikes. Of late, more number of injuries are being evaluated with magnet resonance imaging (MRI).[1] Therefore, in the relevant clinical scenario, recognizing the imaging characteristics of electrical injury is important, both for its relevance in investigating sequelae to electrical injuries and to differentiate these imaging appearances from other disease processes.
Discussion
The evaluation of cerebral electric injuries [2] is limited due to the sporadic nature of electrical injury. The available literature mostly consists of case reports [3],[4] and animal experiments. Radiology plays an important role in the investigation for these kinds of accidents. The mechanisms by which electricity causes bodily injury are not completely defined but include several pathways. The most important is thermal,[5] when current passing through the victim producing large quantities of heat resulting in external and internal burns. In another postulated mechanism called electroporation,[5] membrane proteins permanently change their structural arrangement and can no longer maintain transmembrane ion gradients, resulting in cell death. In addition, the actual physical forces involved in the injury (i.e., a person loses consciousness and falls from a height as a part of occupation) can injure the victim.
In 1995, Cherington [6] classified electrical injuries into four groups, which helps in understanding electrical injuries, as well as in guiding appropriate imaging.
Immediate and transient: This includes injuries which are evident immediately after the event and they include confusion, paresthesia, amnesia, loss of consciousness, and weakness. These injuries most often resolve within minutes to hours. Computed tomography (CT) of brain is almost negative universally. There are case reports with MRI demonstrating T2W abnormalities consistent with the neurologic symptoms. Follow-up imaging is not performed in most of the cases, but when obtained, the T2 abnormalities seem to partially resolve. As in our patient, imaging obtained 2 months after the insult showed complete resolution of the T2 signal intensity abnormality without significant volume loss.
Immediate and prolonged or permanent: These types of injuries are less common but are debilitating. They include neuronal chromolysis, glial proliferation, hemorrhage, and infarction. The length and severity of the insult, as well as the path of the electricity in the human body are the factors contributing to this category.
Delayed and progressive: This is difficult to categorize clinically. These injuries are also debilitating and receive disproportionate findings on MRI. Various conditions have been reported including myelopathy, basal ganglia disorders, and motor system diseases. They mostly carry a poor prognosis.
Event-associated injuries: This category is important radiologically and include trauma following the insult or hypoxic injures in brain due to cardiac arrest.
Conclusion
Electrical shock injury produces characteristic reversible neuroparenchymal signal intensity alterations, which in the appropriate clinical setting is more or less diagnostic. Follow-up imaging helps to detect resolution of imaging findings, thus confirming the benign nature of the signal intensity alterations.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.
