Hanging isn't a super-common presentation to the ED. When it happens, though, there is often some confusion as to how to investigate and manage the patient. Does everyone need a CT? What kind of CT? How can we tell who is high risk for injuries? And what injuries are we looking for anyway?

Judicial hangings

First, a word about classification. There are technically two kinds of 'hanging': judicial and non-judicial. In the ED we rarely see injuries from judicial hangings, because the person in question would not generally survive to hospital. The combination of careful knot placement directly below the occiput and a sudden drop equivalent to the person's height accounts for the mechanism of injury: forceful distraction of the cervical spine, complete cord transection and death.

Non-judicial hangings and strangulation

The pathophysiology in non-judicial hangings (and strangulation) is quite different, and being aware of it will help us to understand the types of injuries to look for. The mechanism of injury is as follows. Sustained pressure on the neck leads to compression of the jugular veins, which are quite superficial, and this obstructs cerebral outflow. The resulting stagnant hypoxia leads to loss of consciousness in as little as 15 seconds. When this happens, muscle tone decreases and the weight of the patient is placed more fully on the neck.

Death in such cases is usually the result of arterial occlusion and hypoxic brain injury. Interestingly, external compression of the pharynx and trachea requires a lot of force and is not thought to play a significant role.

Which injuries are we concerned about?

Cervical spine fractures are rare in non-judicial hangings, but the bony, cartilaginous and soft tissue structures of the anterior neck are more vulnerable to injury. These can be categorised in two groups:

1. Fractures or contusions of the cricoid, hyoid, laryngeal cartilages or epiglottis. Cricoid fractures in particular can lead to airway obstruction (being the only complete ring), but any of these injuries put the airway at risk because of the resultant bleeding or oedema. Plain radiographs may show subcutaneous emphysema or a hyoid fracture, but CT neck is more sensitive for cartilagenous injuries and should be performed if suspicion is high.

2. Blunt vascular injuries. The commonest mechanism for this is compression of the common carotid artery against the transverse processes of C4-6. This can lead to dissection or intramural thrombus. CT angiography (CTA) is the imaging modality of choice for detecting these injuries. Vascular injuries can be missed on regular CT so it's worth actively considering them in every hanging victim as a cognitive forcing strategy.

What does the literature say?

Three recent retrospective studies^{​[1–3]​} have looked at the incidence of significant injury after hanging / strangulation. An informal pool of their data reveals that out of 552 cases, only 6 had clinically significant injuries. Each of the authors concluded that having a normal GCS and no signs or symptoms of aerodigestive injury (see below) effectively ruled out significant pathology. The low incidence of injury makes me a little cautious about adopting blanket 'rule out' criteria, but these data are certainly reassuring.

Schberg S, Gupta N, Shah K. Aggressive imaging protocol for hanging patients yields no significant findings: over-imaging of hanging injuries. Am J Emerg Med. 2019;37(4):737-9^​[1]​

A review of 78 patients, each of which received extensive CT imaging. Only 2 patients had significant findings. One had a sternum fracture with subcutaneous air, and the other had a mild dislocation of the thyroid cartilage, which was reviewed by ENT and required no follow up.

Matusz E, Schaffer J, Bachmeier B, et al. Evaluation of nonfatal strangulation in alert adults. Ann Emerg Med. 2019 [epub ahead of print]^​[2]​

A review of 349 cases of manual strangulation, 60% of whom received advanced imaging. Injuries were identified in 2 cases, both cervical artery dissections. Both of these patients presented with dysphagia.

Time for one more study?

Subramanian M, Hranjec T, Liu L, et al. A case for less workup in near hanging. J Trauma Acute Care Surg. 2016;81(5):925-30^​[3]​

A review of 125 patients, each of which received extensive CT and MRI imaging. Only 2 significant injuries were found. They found that having a normal GCS and no signs or symptoms of aerodigestive injury effectively ruled out significant pathology.

Which clinical features suggest significant injury?

The most extensive review of the best evidence-based management of strangulation victims comes from a 2010 paper.^​[4]​ The authors suggest that the presence of any of the following features necessitates CT head and neck, with CTA being reserved for those who remain unconscious or have neurological signs...

Symptoms

• Reduced level of consciousness on arrival or at scene


• Breathlessness


• Dysphagia


• Hoarse voice

Signs

• Erythema or ecchymosis on the neck


• Any neurological deficit


• Laryngeal crepitus


• Facial or conjunctival petechiae

This seems as good a list as any to guide our management. Job done!

1. 
   
   
   

   Schuberg S, Gupta N, Shah K. Aggressive imaging protocol for hanging patients yields no significant findings: Over-imaging of hanging injuries. Am J Emerg Med [Internet] 2019;37(4):737–9. Available from: https://www.ncbi.nlm.nih.gov/pubmed/30630681

   
   
   
   


2. 
   
   
   

   Matusz E, Schaffer J, Bachmeier B, Kirschner J, Musey P, Roumpf S, et al. Evaluation of Nonfatal Strangulation in Alert Adults. Ann Emerg Med [Internet] 2019;Available from: https://www.ncbi.nlm.nih.gov/pubmed/31591013

   
   
   
   


3. 
   
   
   

   Subramanian M, Hranjec T, Liu L, Hodgman E, Minshall C, Minei J. A case for less workup in near hanging. J Trauma Acute Care Surg [Internet] 2016;81(5):925–30. Available from: https://www.ncbi.nlm.nih.gov/pubmed/27537511

   
   
   
   


4. 
   
   
   

   Stapczynski S. Strangulation Injuries. Emergency Medicine Reports [Internet] 2010;Available from: https://www.reliasmedia.com/articles/19950-strangulation-injuries