Hanging and strangulation (trauma)

Hanging and strangulation are injuries involving constricting pressure applied to the neck.

Epidemiology

In America hangings are the second most common form of suicide after firearm use. In other parts of the world due to the relative difficulty in accessing firearms, hangings are the most common form of suicide ¹.

Clinical presentation

Patients may be dead on arrival or with an altered level of consciousness. Bruising or lacerations may be visible around the neck. Airway comprisecompromise may be present ².

Pathology

Hangings are in fact a type of strangulation, along with ligature strangulation and manual strangulation. Hangings and strangulations can all be accidental, self-inflicted (e.g. in suicide) or intentional (e.g. judicial hangings) ³.

• hanging: a constricting band placed around the neck which constricts due to the effect of gravity by either the entire body hanging (called a complete hanging) or a part of the body hanging (called an incomplete hanging)
• ligature strangulation: a constricting object or band placed around the neck which is tightened by a force other than gravity
• manual strangulation: a force applied to the neck directly by body parts (e.g. hands, arms, legs)

In suicidal hanging the forces exerted on the neck are usually lower than those seen in judicial hangings due to absence of the drop height in such hangings, making cervical spine injury less of a concern (see Hangmanhangman fracture). Vascular injury (e.g. carotid dissection) is an important site of injury to consider as well ⁴. Fractures of the trachea, cricoid and hyoid bone can also occur ⁵. Hypoxic brain injury due to asphyxia and/or vascular occlusion is an often fatal complication ⁵.

The pathophysiology of hanging and strangulation induced-induced death includes multiple processes such as ⁴:

• carotid sinus stimulation induced cardiac arrest
• asphyxia (caused by airway compression)
• vascular occlusion
• spinal cord or brainstem damage

Radiographic features

Plain film

Plain film can be used to demonstrate the pulmonary complications which are common in survivors of near-hanging injuries such as pulmonary oedema, pneumoniapneumonia and ARDS.

CT

CT can evaluate injury to the soft tissues, airway cartilage and bones of the neck. CT of the brain may reveal cerebral oedema and hypoxic-ischaemic encephalopathy ⁵. 

CT angiogram

CT angiogram of the neck vessels should be performed to demonstrate the presence of any vascular injury (e.g. blunt cerebrovascular injury) ⁵.

MRI

MRI of the brain can further demonstrate any hypoxic-ischaemic brain/spinal cord injury in greater levels of detail ⁵. 

Treatment and prognosis

Hangings overall carry a 70% mortality rate, but of patients who arrive at hospital 80% survive often with no lasting neurological deficit ¹.