Electric or traumatic injury? The role of histopathological investigations

Abstract

Analysis of wounds is crucial in forensic medicine to prove how an injury was caused. In many cases, microscopic analysis may be decisive. It is often difficult to distinguish macroscopic skin lesions resulting from electrical, mechanical and from thermal trauma where these occur simultaneously and to formulate a correct differential diagnosis. We report two cases in which the injuries found on the bodies and the manner of death raised uncertainty. An autopsy was performed. External examination of the bodies showed skin injuries that needed histopathological analysis to reconstruct the dynamics and the manner of death which has an important role in doubtful cases.

Keywords

Electrocution autopsy differential diagnosis of cause of death – traumatic injury histopathological investigation forensic sciences

Introduction

Wound examination is of prime importance in forensic pathology, and forensic pathologists are often asked to explain how and by what means a wound was made. Macroscopic observation may be insufficient for accuracy.¹ The macroscopic and histological interpretation of even minor wounds is important forensically, and while electrical injuries are relatively rare, they can cause a potentially devastating multisystem injury with high morbidity and mortality.^2,3 Some authors have analysed the histopathological characteristics for differential diagnosis of skin lesions caused by electrocution, flame and abrasion. The purpose of this study is to determine the crucial role of lesion analysis when reconstructing the dynamics and manner of death. We report two cases in which there was uncertainty about the injuries on the bodies.

Cases

Case 1

A 50-year old-worker on a building site was found dead. A high-voltage cable was situated a few metres away from the roof of the house which was under construction. The deceased was lying in a supine position, about half a metre from scaffolding, and had suffered typical fall injuries: lacerated contused wounds, abrasions (Figures 1 and 2) and skull fractures. After undressing the corpse, a careful analysis of macroscopic lesions highlighted some injuries of dubious aetiological interpretation.

Figure 1.

Red abrasions on the back.

Figure 2.

Lacerated contused wounds and abrasions on the foot.

Case 2

A worker aged about 30 was found dead on farm land. Circumstantial data revealed a high-voltage trellis taller than 10 m. The body had a range of different injuries (Figures 3 and 4).

Figure 3.

Other traumatic injuries from fall.

Figure 4.

Electrical abrasions showing a yellowish colour with pergameneous feature abrasions.

Materials and methods

In both cases, external examination and an autopsy were carried out, and samples of skin, subcutaneous tissue and muscle of all body tissues abrasion were taken and cutaneous and muscular fragments were collected. The biological tissue samples were preserved in 10% formaldehyde and then embedded in paraffin. The inclusions were stained using haematoxylin-eosin technique. The histological investigation was carried out according to a standard protocol using paraffin-embedded formalin-fixed samples and preparation of slides. Each sample was catalogued before delivery to the pathology laboratory. The data obtained were compared.

Results

In both cases, the electrical abrasions showed a yellowish colour with pergameneous features, similar to a localised mummification, with the presence of dry wounds and mild blackish punctuation due to carbonaceous residues. The other abrasions (with no electricity aetiology) presented a reddish colour, clammy skin and moist wounds. The results of this study showed that some morphological changes detected by histological examination may help in the differential diagnosis between electrical and fall injuries. In both cases, the histopathological examination performed on the skin, subcutaneous and muscle samples showed wounds compatible with electric aetiology, such as:

Presence of small cavities or air bubbles (alveolus by high temperature) in the stratum corneum of the epidermis, with carbonaceous residues on the surface (Figure 5).

Polarisation and elongation in clumps of cells of the stratum basale, stratum spinosum (Figure 6).

Coagulative necrosis of the dermal connective underlying with densification and homogenisation of the connective tissue bundles of the dermis (Figure 7). The cytoplasm and the nucleus of these cells were dense, homogeneous and hyperchromatic (Figure 8).

Figure 5.

Air bubbles in the stratum corneum of the epidermis with carbonaceous residues on the surface.

Figure 6.

Polarisation and elongation in clumps of cells.

Figure 7.

Coagulative necrosis of the dermal connective.

Figure 8.

Homogeneous and hyperchromatic nucleus.

The microscopic data of histopathological investigation of injuries caused by electric current were compared with the macroscopic data from the external examination. In both cases, the combined findings of macroscopic and microscopic examinations enabled us to determine the route of the electric discharge, from the entry point to the exit point.

Discussion

The study demonstrates the following issues to consider where there has been electrocution with a subsequent fall:

it is important to check for specific lesions caused by electricity where there is uncertainty;

macroscopic evaluation of the skin lesions, to arrive at a correct differential diagnosis between electrical and other traumatic aetiology;

morphological observation of skin lesions, with special attention (when another lesion is present) to colour, humidity, margins, loss of substance, presence of blackish marks, distance of the electrical mark;

locating the point of fall, by checking for the presence of any electrical conductors and the place where the corpse is found.

In both cases, following an electric shock from an electric line carrying 20,000 V, the deceased fell to the ground. The most significant histological evidence for a differential diagnosis as defined by İbrahim Üzün et al. is as follows:

Intra-epidermal separation is the most common result from electrical lesions and sub-epidermal separation in flame burns.

If there is just intra-epidermal separation or a combination of intra-epidermal and sub-epidermal separation in a lesion, it is probably caused by electricity.

Epidermal nuclear elongations most probably occur in electrical lesions, as the abrasions may have mild nuclear elongations.

Dark nuclear staining can be marked and homogenisation can be deep in abrasions.

If there is a slight elongation of epidermal nuclei, marked dark staining in the nuclei and widespread homogenisation in the dermis in a lesion, that lesion is most likely to be an abrasion.^4–9

Therefore, in this study, we want to emphasise the crucial importance, during a forensic inspection, of the detection of macroscopic injuries with electrical features in order to perform an appropriate autopsy. Histopathological examination^9,10 is the most accurate means of detecting injuries of electric aetiology, but due to the time this procedure takes, there will be no immediate answers after the event.

In such cases, the histopathological examination of skin samples taken during the autopsy allows us to:

confirm the macroscopic data emerging in the external examination;

demonstrate the compatibility of the lesions with the electrical aetiology;

show the passage of electrical current from the entry point to the exit point.

Footnotes

Declaration of conflicting interests

The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Funding

The author(s) received no financial support for the research, authorship, and/or publication of this article.

References

Kondo

Ohshima

. The role of an operating microscope in medico-legal practice. J Clin Forensic Med 1995; 2: 73–79.

Camps

. Interpretation of wounds. Br Med 1952; 2: 770–772.

Bingham

. Electrical burns. Clin Plast Surg 1986; 13: 75–85.

Üzün

Akyildiz

Inanici

. Histopathological differentiation of skin lesions caused by electrocution, flame burns and abrasion. Forensic Sci Int 2008; 178: 157–161.

Al-Alousi

. Homicide by electrocution. Med Sci Law 1990; 30: 239–246.

Takamiya

Saigusa

Nakayashiki

et al.

A histological study on the mechanism of epidermal nuclear elongation in electrical and burn injuries. Int J Legal Med 2001; 115: 152–157.

Oehmichen

Cropelin

. Temporal course of intravital and postmortem proliferation of epidermal cells after mechanical injury. An immunohistochemical study using bromodeoxyuridine in rats. Int J Legal Med 1995; 107: 257–262.

Thomsen

Danielsen

Nielsen

et al.

Epidermal changes in heat and electrically injured pig skin. A light microscopic study of the influence of heat energy intensity and electrical current frequency. Acta Pathol Microbiol Immunol Scand 1983; 91: 297–306.

Aquila

Boca

Caputo

et al.

An unusual case of sudden death: is there a relationship between thyroid disorders and fatal pulmonary thromboembolism? A case report and review of literature. Am J Forensic Med Pathol 2017; 38: 229–232.

10.

Aquila

Pepe

Di Nunzio

et al.

Suicide case due to phosphoric acid ingestion: case report and review of literature. J Forensic Sci 2014; 59: 1665–1667.