Hanging Injuries and Strangulation

Practice Essentials

With its relatively small diameter, lack of bony shielding, and close association of the airway, spinal cord, and major vessels, the human neck is uniquely vulnerable to life-threatening injuries. Throughout recorded history, various methods of strangulation (ie, disruption of normal blood and air passage in the neck) have been used by both assailants and penal systems to produce injury and death.

Hanging is a form of strangulation that involves suspension by the neck. Hangings can be classified as either complete or incomplete. When the whole body hangs off the ground and the entire weight of the victim is suspended at the neck, the hanging is said to be complete. Incomplete hangings imply that some part of the body is touching the ground and that the weight of the victim is not fully supported by the neck. Hangings may also be classified by intent (eg, homicidal, suicidal, autoerotic, accidental).

Significant cervical spinal cord and bony injuries are most common in hangings that involve a fall from a distance greater than the height of the victim. The prognosis in such injuries is dismal.

Several specific patterns of presentations are common.

• Assault victims may present after being either manually strangled or garroted.
• Hanging victims may be brought to the emergency department by Emergency Medical Services (EMS) after being found by strangers, friends, or family members. These patients may have been suicidal. However, they also may have been experimenting with autoerotic asphyxia, or other forms of "breath play," and were hanged by accident. (See Causes.) Attempts to determine the height of the drop in near-hanging victims are important, as different patterns of injury occur as the drop height increases. This, in turn, affects management.
• Infants generally present after being caught by the neck between crib slats, fence slats, or on objects such as hanging window cords.

Physical signs include the following:

• Abrasions, lacerations, contusions, or edema to the neck, depending on how the patient was strangled
• Subconjunctival and skin petechiae cephalad to the site of choking (Tardieu spots)
• Severe pain on gentle palpation of the larynx, which may indicate laryngeal fracture^[1]
• Mild cough
• Stridor
• Muffled voice
• Respiratory distress
• Hypoxia (usually a late finding)
• Mental status changes

Common causes of strangulation injuries include the following:

• Assault: Risk factors follow other types of assault, with the exception that women are more likely than men to be victims of strangulation.
• Depression can lead to hangings, especially in subgroups (eg, prisons, where hangings are easier to do than other methods) or veterans.^[2]
• Erotic experimentation: Some people experiment with hypoxia as a means of intensifying orgasm. Marquis de Sade first described this practice in his writings. Autoerotic play using a ligature or noose to produce hypoxia during masturbation can result in accidental strangulation.^[3]  Sado-masochistic activities can also result in inadvertent death.^[4]
• Another form of "breath play" is increasingly common among adolescent and young adults. Most commonly known as the "choking game," it involves voluntary choking, throttling, or near-hanging in order to enjoy the altered sensations that occur as the "player" becomes unconscious.^{[5, 6]}  Other slang names at this writing include "flatline," "space monkey," and "suffocation roulette."

C-spine stabilization and airway assessment are of paramount importance.

Do not attempt endotracheal intubation in the field unless the airway is acutely compromised.

If respiratory failure or airway obstruction is present, prehospital intubation of the patient is indicated.

Consider early consultation with trauma, ENT, trauma, or general surgery for strangulation injuries.

Psychiatric consultation should be obtained in cases of suicidal or autoerotic strangulation.

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Pathophysiology

The pathophysiology of morbidity and mortality from strangulation injuries is controversial, save for the case of judicial hangings. In a judicial hanging, the drop is at least as long as the height of the victim and the hanging is complete. The mechanism of death is effectively decapitation, with distraction of the head from the neck and torso, fracture of the upper cervical spine (typically traumatic spondylolysis of C2 in the classic hangman fracture), and transection of the spinal cord.^[7] Direct spinal cord injury may or may not be the cause of death in suicidal hangings.

In other mechanisms of strangulation injuries, whether by manual choking, application of tool or ligature, or postural asphyxiation (eg, children whose necks are caught in an object such as a crib, a hanging towel loop, or a window cord), pathophysiologic theories to account for observed outcome include the following:

• Venous obstruction, leading to cerebral stagnation, hypoxia, and unconsciousness, which, in turn, produces loss of muscle tone and final arterial and airway obstruction
• Arterial spasm due to carotid pressure, leading to low cerebral blood flow and collapse
• Vagal collapse, caused by pressure to the carotid sinuses and increased parasympathetic tone

Interestingly, none of the proposed mechanisms treats airway compromise as the immediate cause of collapse. In fact, although mechanical airway compromise occurs and ultimately complicates patient management, it appears to play a minimal role in the immediate death of victims of successful strangulation. Many jujitsu and aikido strangles (eg, hadaka-jime and variants) are applied to the vascular structures of the neck and not the trachea. Several reports exist of suicidal posttracheostomy patients who successfully hung themselves with ligatures well above the tracheostomy, where death did not appear to be related to spinal cord injury.

Most experts agree that regardless of the events occurring in any given hanging or strangulation, death ultimately occurs from cerebral hypoxia and ischemic neuronal death.

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Epidemiology

Frequency

The National Center for Injury Prevention and Control has reported 13,920 deaths annually nationwide from "suffocation," for an age-adjusted rate of 4.63 per 100,000. This includes "other accidental hanging and strangulation (category) W76", "accidental suffocation and strangulation in bed, W75", "hanging, strangulation, and suffocation, Y20", and the portmanteau category "other accidental threats to breathing, W75-W84".^[8]

In 2012, 24.8% of suicides in adults (8,016 men, 2,072 women) were estimated to have been caused by hanging or suffocation.^{[9, 10]}

Strangling injuries are common, as the necessary weapons are as close as the attacker's own hands. An estimated 5-10% of urban assaults involve strangulations or ligature assaults.

Judicial hangings are uncommon worldwide. However, accidental hanging and strangulation injuries are becoming more prevalent in urban centers.^{[11, 12]} Causes include an increased prevalence of the "choking game" and autoerotic "breath play" (see Causes).^{[5, 6]}

Mortality/Morbidity

If death is not immediate, the risk of delayed airway obstruction is significant. Tracheal intubation can be difficult if laryngeal edema is present or if direct traumatic disruption of the larynx has occurred. Strangulation injuries account for approximately 2.5% of all traumatic deaths worldwide.

Women are victims of strangulation assault more frequently than men. In contrast, nearly all reported autoerotic strangulation deaths involve men. Suicidal hangings were once considered to be far more common among men. Recent trends suggest that women are increasingly likely to use hanging than other common methods of suicide (firearms and poisoning).

Several populations are at risk of hanging or strangulation. Toddlers in postural asphyxiation: Ill-constructed cribs allow toddlers to be caught by the neck and strangled as they put their heads out. Window cords have also been implicated in such deaths. In adolescents, suicidal depression can lead to hanging. There appears to be an increasing incidence of accidental hanging and strangulation due to "the choking game," a practice involving voluntary near-strangulation in order to enjoy the altered mental state and physical sensations. In young adults, autoerotic accidents, assault, and suicidal depression are common causes. Prison inmates often choose hanging if suicidal; it is one of the few methods available to them.

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Complications

Complications include the following::

• Respiratory complications: These are the major cause of delayed mortality in near-hanging victims. Both aspiration pneumonia and ARDS may develop, complicating the clinical course.
• Tracheal stenosis
• Neurologic sequelae: A wide array of complications may occur in survivors of strangulations and near-hangings, including muscle spasms, transient hemiplegia, central cord syndrome, and seizures.^[13]  Spinal cord injury can also cause long-term paraplegia or quadriplegia and short-term autonomic dysfunction.
• Scarring of neck tissue
• Psychiatric disturbances: Psychosis, Korsakoff syndrome, amnesia, and progressive dementia all have been reported after surviving a hanging or strangulation. Nearly all patients who have undergone strangulation or near-hanging demonstrate restlessness and a propensity for violence.

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Approach Considerations

Laboratory tests should not be drawn until after the airway has been assessed and, if necessary, secured. Arterial blood gases (ABGs) analysis should be obtained in all patients who require intubation, for subsequent ventilator management. Given the ready availability of pulse oximetry, ABGs are unnecessary in patients who do not require endotracheal intubation.

In patients who are not at immediate risk of airway compromise, direct fiberoptic laryngoscopy and microlaryngoscopy may play a role in establishing the full pattern of injuries. An ENT consultation can establish both the need for, and the timing of, these studies.

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Imaging Studies

Judicial hangings are characterized by drops that are greater than the victim's height. In such drops, the head hyperextends as the noose stops the victim. Classically, the result is bilateral fracture through the pedicles of C2; the body of C2 is displaced anterior to the vertebral body of C3.

In nonjudicial hangings, cervical spine injury is rare. However, laryngeal injuries can result.^[14]  Traumatic vascular thrombosis can occur as a result of the pressures placed on the vascular structures by the ligature. Such injuries can also be caused by garroting.

Given these varied injuries and the superiority of CT over plain films in the evaluation of the cervical spine, ^[15]  early CT imaging and CT angiography should be obtained in any symptomatic hanging survivor. If there is any neurologic abnormality on initial assessment, CT imaging of the head is also indicated. MRI may have a role in further defining injuries found at initial imaging.

As always, chest radiographs are indicated after endotracheal intubation for placement confirmation and to establish a baseline against which to measure the patient's course. Acute respiratory distress syndrome (ARDS) can occur as a complication of these injuries.

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Emergency Department Care

Assessment and treatment of airway status and breathing is paramount. In assessing the patient prior to possible endotracheal intubation, the likelihood of spinal cord injury increases substantially in hanging victims whose drop was equal to or greater than their height, even in incomplete hangings. Fluid resuscitation must be performed judiciously, given the risk of subsequent ARDS and cerebral edema.

Monitor the patient for cardiac arrhythmias.

Endotracheal intubation may become necessary with very little warning.

Cricothyroidotomy is indicated for any patient with airway deterioration, should endotracheal intubation be unsuccessful.

If associated neck injuries render cricothyroidotomy difficult, percutaneous translaryngeal ventilation may be used to temporarily oxygenate a patient. Definitive airway management (laryngotomy) must follow swiftly.

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