What We Don’t See in the Shadows

Some pathologies are like fiends, lurking in shadows, often unseen, and certainly under-recognised. Non-fatal strangulation (NFS) is one of those.

Although there’s nothing new about NFS as an act of violence and control, it is only recently that we as clinicians have understood what makes it unique.

All around the world, legislation is falling into line with NFS, with legal ramifications commensurate with the seriousness of it as a crime. Now we, in medicine, are catching up with the law.

What is interesting, however, is understanding why we’ve been so slow to register NFS as the deadly act it is. We now know that a single episode of NFS increases a victim’s risk of being killed at the hands of that same perpetrator up to seven times. It has been described as being ‘on the edge of homicide’; not just an act of violence, but of cold, calculating control. It says, ‘with my bare hands, I can take your life.’  It takes not much more than the strength of a handshake to kill. To parse the reasons why we have been slow on the uptake, the following points may go some way to explaining.

• We ask the wrong questions. If we enquire whether a victim has been strangled, they may not register the even for what it was, as though strangulation only occurs like the movie version. Instead, we should ask whether the patient has had any sort of pressure placed on the neck. Perhaps it was a knee, or a weapon, or a ligature. We also need to ask questions aslant – ‘did you black out, wake up on the floor, lose control of bowels or bladder?’ – all of these being consequences of hypoxia.
• The victim may not recall the event – anoxia happens quickly, and the centres for memory can be affected rapidly. If this is not the first time, we may need to think about it in the same way as repeated concussion injury, with cumulative anoxic injury contributing to neuropsychiatric sequelae, including further memory loss, as well as other cognitive changes.
• We don’t appreciate the fact that less than fifty percent have external signs of injury (such as ligature marks, abrasions, the classic petechial haemorrhage distribution, defensive scratch marks), leading us to underestimate the severity of the assault.
• We don’t consider how little force it takes to cause serious injury, and how quickly it can occur. The four proposed mechanisms for potentially fatal outcomes in NFS are 1) jugular venous obstruction, causing sudden severe venous congestion. It takes less pressure than is required to open a can of coke to achieve this. 2) carotid artery compression. Still requiring less force than a firm handshake, loss of consciousness from hypoxia can occur within ten seconds. 3) airway compression requires greater and more sustained force, but can still result in hypoxia, as well as aerodigestive injury. 4) more a postulated mechanism is carotid body compression/stimulation with subsequent brady-asystolic arrythmias.
• We may overlook the important sequelae. Carotid artery dissection is uncommon, but may be missed, resulting in long term disability. The nature of NFS, with intermittent arterial compression with torsion from twisting movements, has been demonstrated to cause arterial injury. Thus, if there is any suspicion at all, a CT angiogram needs to be requested.
• We may not even get to the starting point. Victims of intimate partner and family violence may not feel able to answer our hurried, targeted questions. Leaving a non-judgemental, caring space wide open for the victims to speak, and to be believed, is vital.

Thus, NFS can be considered the newest of old conditions. By increasing our level of suspicion, asking the right questions in the right ways, we have it within our own hands to save a life.