Accidental and occupational ligature strangulation in northern Tunisia: four-case study

Our work looked into the aspects of accidental and occupational strangulation in Tunisia. It is a four-case report of accidental strangulation autopsied in the Forensic Department of Tunis during the period between 2007 and 2015, which is the only department that performs forensic autopsies (around 2000 per year) of corpses from almost all the northern part of Tunisia (10 out of 24 districts of Tunisia, about 42% of the total population (4.6 million) (National Institute of Statistics, 2017). We reported four cases of accidental strangulation causing the death of four farmers. The lesions found in the external examination and in the autopsy were discussed according to the existing literature. The aim of the study is to discuss through these cases the particular aspects of this rare forensic shape of strangulation, as well as the prevention of these accidents. The issue of the discussion was to conclude the preventive measures.

Strangulation is a common way for homicides (Aggarwal and Agarwal 1998; Shetty and Shetty 2006; Deidiker 1999; Gupta et al. 2004; Kohli et al. 1996; Verma et al. 2005; Verma and Lal 2006). Although accidental strangulation is rare, it is occasionally reported knowing that the circumstantial evidence alone can indicate the nature of the occurrence. Accidental strangulation is uncommon but more frequent in children (accidental hanging) or elderly persons (Aggarwal and Agarwal 1998; Kohli et al. 1996). However, cases of accidental hypoxia after auto-erotic deaths and after thefts were also reported in the literature (Saukko and Knight 2016).

The cause of death in our cases was asphyxia. It was secondary to brain vessel occlusion in two cases, to tracheal disruption in one case and to a cervical contusion in another case. Petechiae and congestion are caused by an acute rise in venous pressure. Congestion is often associated with tissue swelling. The oedema is the result of a fast transudation, within few minutes, through the capillary and venule walls. It concerns essentially the brain and the lungs.

In cases 2 and 4, cervical and thoracic subcutaneous emphysema were also reported in the autopsy findings. This particular and antemortem sign was already described in the literature and explained by any cause of sudden increase in intra-alveolar pressure (e.g. blunt trauma, tracheal intubation or an interruption of respiratory mucosa) (Saukko and Knight 2016).

The mechanism of death depends on two factors: the amount of resistance made by the victim and the amount of force of the moving machine. In some cases of accidental strangulation, death was due to the compression of the neck leading to tracheal and esophageal disruption. It was reported in the literature that about half of the cases of ligature strangulations may show the fracture of the neck structures (Souza et al. 2013).

In our study, an unusual case of fracture and dislocation of the cervical vertebra inducing accidental ligature strangulation was reported (case 4). Fracture and dislocation of the cervical vertebra are seen in hangings associated with a long drop or with a heavy body, but it is not reported in ligature strangulation. We assumed that the great force exerted by the combine harvester caused probably a violent hyperextension of the neck causing the disjunction of the cervical vertebra and the contusion of the spinal cord. In hangings associated with a long drop or with a heavy body, lesions are much more severe with total separation of the vertebra and a rupture of the spinal cord (Saukko and Knight 2016).

In adults, accidental ligature strangulation usually involves an article of clothing (Aggarwal and Agarwal 1998; Shetty and Shetty 2006; Deidiker 1999; Kohli et al. 1996; Verma et al. 2005) becoming entangled in some moving machine causing a major constriction of the neck. In our cases, machines responsible for this kind of strangulation were tractors, a combine harvester and a well drive pipe. In literature, we have seen also motor vehicles, industrial machinery, household objects and ironing machines (Aggarwal and Agarwal 1998; Shetty and Shetty 2006; Gupta et al. 2004; Kohli et al. 1996; Verma et al. 2005; Verma and Lal 2006). As stated, the common mechanism in this type of strangulation is the progressive constriction of the neck made by an article of the victim’s clothing.

A striking fact that has been noticed, in the literature, is the frequency of the phenomenon of accidental strangulation in India (Aggarwal and Agarwal 1998; Shetty and Shetty 2006; Gupta et al. 2004; Kohli et al. 1996; Verma et al. 2005; Verma and Lal 2006; Verma 2007; Chattopadhyay and Pal 2008; Singh et al. 2003). This frequency is probably related to particularities of clothing (“chunni” around the neck) and the means of transport used in this country (tricycles with unprotected wheels).

Various cases of accidental strangulation have been reported in children and infants (Aggarwal and Agarwal 1998; Saukko and Knight 2016). These children became entangled mostly in cords while playing.

This particular mode of accidental death shows the importance of careful and proper handling of the mechanical device, even the most innocuous ones, for the prevention of these work accidents. It also sheds the light on the importance of the prevention of domestic accidents including infants by watching them carefully and protecting windows. A strict implementation of dress code and abandoning loose apparel is needed in such workplaces. In India, using protection while driving and avoiding chunnies while taking transports may be a means to prevent these accidents (Verma 2007; Saukko and Knight 2016).

Accidental strangulation remains rare. It returns especially within the framework of an industrial accident (clothes stuck in machines). Particular findings such as tracheal and esophageal disruption and cervical vertebra disjunction are uncommon but were also found in our cases.

The prevention of this type of accident often goes through simple and effective measures such as respect for the work uniform and the awareness of the workers.