The cross-sectional analytical study was conducted on 40 dead bodies brought to the mortuary of a tertiary care institution, with history of death due to electric shock over a period of two years from April 2007 to March 2009. Another 20 corpses, who had not died due to electric current injury, but were given the same after death, were taken as control. The electric current (220 V) was applied to control cases at different sites.

All the 40 cases were thoroughly examined for medicolegal purposes at the time of conducting postmortem examination and findings were recorded as per proforma attached. Skin was examined for the wound of entry and exit (if any) of electric current injury. Skin biopsies, from the electric current injury sites of the deceased, were taken from the edge of the wound and subjected to histopathological examination. Histopathological examination was carried out as described by Culling CFA et al., using haematoxylin and eosin staining [11].

Over a period of two years, 1748 cases were brought to the mortuary, of which, 40 cases were brought by the police with the alleged cause of death to be electric shock. Incidence of electric shock was 2.2% of total autopsies. Male (n=37) to female (n=3) ratio was 12.5:1, with most of the victims (62.5%) aged 20-40 years. Death was reported within 30 minutes of electrocution in 92.5% of the cases [Table/Fig-1].

Epidermis and dermis were involved in 28 (70%) of the cases while blister formation, metallisation or inflammatory response of the tissues was not present in any of the cases. In 34 (85%) of the cases, clothing of the deceased was not involved. Of these 6 out of 40 cases, clothing of 5 (12.5%) persons was involved due to flash burns, while in 1 (2.5%) case clothing was involved due to lightening. Exit wound of electric current injury was not present in any of the victims of electric current injury cases in present study.

Epidermis was found burnt/charred [Table/Fig-2] in 18 (45%) of cases and bulla formation [Table/Fig-3] was present in 9 (22.5%) of the cases under study. Epidermal papillae were flattened [Table/Fig-4] in 19 cases (47.5%). Vesicular nuclei [Table/Fig-5] were seen in 2.5% cases. No significant change in epidermal cells of skin was seen in 3 (7.5%) of the cases.

[Table/Fig-2]:

Microphotograph showing charring of the epidermis with necrosis in the underlying dermis (100X).

[Table/Fig-3]:

Microphotograph showing bulla formation (100X).

[Table/Fig-4]:

Microphotograph showing flattening of papillae (400X).

[Table/Fig-5]:

Microphotograph showing vesicular nuclei in the epidermis (400X).

In 25 (62.5%) cases, necrotic changes [Table/Fig-6] were observed, adnexal structures were intact in 9 (22.5%) cases. Vacuolated appearance in dermis was seen in 5 (12.5%) cases. Charring and flattening of papillae were observed in 3 (7.5%) cases each in the study. Bulla formation in dermis was seen in 2 (5%) cases.

[Table/Fig-6]:

Microphotograph showing marked necrosis in the dermis (100X).

In none of the cases under study, inflammatory change or metallisation/calcification was noted. In the 20 control cases studied, charring of the skin was present in the epidermis/dermis and no further change in the epidermis/dermis were present in any of the control cases.

In the present study, attempt has been made to know the histopathological changes in the skin as a result of electric current injury. Electric burn injury marks often appear as painless, depressed, yellow-grey, punctate areas with central necrosis. Isolated thermal burns may also be seen when clothing ignites. Superficial electric current injury may appear to be linear, punctate, feathering, or thermal burns. In high-voltage electric current injuries, muscle necrosis can extend to sites distant from the observed skin injury, and compartment syndromes occur as a result of vascular ischaemia and muscle oedema, further resulting in delayed thrombosis and haemorrhage [12].

We found 15% cases to have burnt clothing, but no such similar study could be found except generalised statements that clothing or shoes may be burnt in high voltage electrocution cases. In our study, visible electric current injury mark was seen in 85% cases; similarly most studies report visible marks in 62.5-100% cases [13-19]; however, one study reported visible burns in only 5.71-47.25% cases [20].

This is correct as per “Gross changes” in [Table/Fig-1] Laceration and deeper tissue involvement was noted in 7.5% cases. One study reported lacerations in 9.4% cases [15]. Blister formation, metallisation or inflammatory change was not present grossly in any of the cases studied. Various studies have described blistering in 9.4-21.98% cases [15,20]. Metallisation has been reported in one study in 2.2% cases [20]. Some authors have described erythema in 34.4% [15] cases; petechiae in 11.5% [14] and 48.3% [17] cases; and hyperkeratosis in 1.6% [15] and 45.4% [16] cases [Table/Fig-2].

On microscopic examination of the affected part of the skin, bulla formation, flattened papillae, vesicular nucleus and burnt epidermis were seen; the changes typical of electric current trauma. While doing microscopic examination of the dermal layer of the affected skin, necrotic changes, bulla formation, vacuolated appearance, intact adnexal structures and flattened dermal papillae were present. Calcification/metallisation or inflammatory change was not present in any of the cases studied, which can be due to the fact that time gap between electrical trauma and death of the victim was less than the usual time taken for these processes to develop microscopically, as reported by Danielsen L et al., [6]. In our study, perhaps no one survived for sufficient time whereby we could not observe the findings similar to them.

Bulla formation was seen in 22.5% cases in epidermis and 5% cases in dermis; whereas, another study described micro-blistering in 81.8% cases [16]. We found flattening of papillae in 47.5% cases in epidermis and 7.5% cases in dermis; however, no similar findings have been reported in other studies. Charring of epidermis was seen in 45% cases and dermis in 7.5% cases; whereas, other studies have reported charring in 46.9% cases [15]. We noted vesicular nuclei in 2.5% cases; whereas, other studies reported pyknotic nuclei in 54.5% cases [16], and nuclear streaming in 2.86-9.89% [20] to 33.3% [13] and 90.9-100% [16,18,19] cases. Epidermal erosion was observed in 12.5% cases and dermal separation in 77.5% cases; whereas, other studies reported dermo-epidermal separation in 33.3% [13], 73.3-83.3% [19], 90.9% [16], 100% [18] cases. Necrotic changes were seen in 62.5% cases; whereas, other studies reported necrosis in 6.3% [15], 46.7% [19], 60% [13], 66.6% [18], 90.9% [16] cases. Vacuolisation was seen in 12.5% cases; whereas, others reported it in 2.86-7.69% [20], 40% [13], 90.6% [15] cases [Table/Fig-7].

The major limitation of the study appears to be the small number of electric current injury cases, though all cases over the two year study period were included. Further studies are recommended for studying the findings in clinical cases admitted with electrocution and extending the study over more number of cases.

Majority of the fatalities occur within first half an hour of electric current injury. Grossly, the electric current injury indicated no blister formation, metallisation or any inflammatory response of the body. Microscopically too, no calcification or metallisation or inflammatory change was observed. Histopathological study in cases of electrocution could help the forensic pathologist in their diagnosis especially in cases with less typical findings or obscure circumstances; although, the microscopic features are not very specific. Electric contact mark is pathognomic of electrocution. Dermo-epidermal separation is a common histopathological finding. Histopathological changes can be used as supportive evidence in giving cause of death in such cases.