Practice Essentials
Almost all the critical structures (blood flow and return; muscular and bony support; air entry and exit; GI entrance) that the body requires to function, even at the most basic level, travel though the neck. However, the neck has a relatively small diameter and is exposed to the environment without any protective shielding, making it vulnerable to numerous life-threatening injuries. Because of the unique location and access to the neck's anatomy, disruption of this critical location can lead to disability and even death.
According to the National Center for Injury Prevention and Disease Control’s National Violent Death Reporting System, suicide from hanging, strangulation, and suffocation constituted 28.9% of suicides, second only to firearms (48.5%). [1] Accidental hanging and strangulation injuries are becoming more prevalent in urban centers. [2, 3] Causes include an increased prevalence of the "choking game" and autoerotic "breath play." [4, 5]
Strangulation is asphyxia by closure of the blood vessels and/or air passages in the neck due to external pressure. Hanging is the suspension (complete or incomplete) of a person's body, with compression due to the body's own weight. What many people consider to be hanging is not actually hanging, since death occurs by fracture/dislocation rather than asphyxia. [6, 7]
In a study of 622 hanging deaths by Tugaleva et al, hyoid and larynx fractures were present in 46 cases (7.3%), with the most common being isolated hyoid fractures. The incidence of cricoid fractures was 0.5%, and the incidence of cervical spine injuries was 1.1%. [8]
Evidence of strangulation includes the following [9, 10] :
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Finger marks around the neck
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Bruising
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Coughing
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Stridor
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Change in voice
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Facial/subconjuctival petechiae
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Laryngeal tenderness [11]
Evidence of hanging includes the following [12, 13, 14, 10] :
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Ligature marks around the neck
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Use of a belt, rope, or cord
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Facial/subconjuctival petechiae
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Retinal/scleral hemorrhage
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Stridor
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. [15] 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.
When a person is strangled (intentional or accidental, such as children who get caught in an object such as a crib's slats, towel loop, or window cords) or hanged, the pathophysiology starts with decreasing blood flow and airflow, leading to cerebral hypoxia and death. [16, 17] Venous obstruction leads to cerebral blood flow stagnation, hypoxia, and unconsciousness. This loss of consciousness causes complete loss of muscle tone. The weight of the body then allows the offending tool to access the cerebral arteries and airway, hastening the hanging. Arterial spasm may occur due to carotid pressure, leading to low cerebral blood flow and collapse. Death occurs from cerebral hypoxia and ischemic neuronal death.
The mechanism of death from hanging 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. [18] Direct spinal cord injury may or may not be the cause of death in suicidal hangings.
Pediatric patients, especially toddlers, can succumb to strangulation by postural asphyxiation from poorly constructed cribs by allowing the neck to be caught between the crib's slats and strangulation to occur as children try to pull their heads out. Window cords may also result in death, tightening around the necks as children try to free themselves. [16, 17] Adolescents are more prone to the effects of strangulation as a result of depression or accidental hanging and strangulation due to life-threatening games such as the "the choking game," which involves voluntary near-strangulation in order to achieve an altered mental state and physical sensation. Autoerotic asphyxiation can also lead to accidental strangulation or hanging.
A survivor of a strangulation or hanging attempt can have permanent damage to any of the structures in the neck, along with CNS disability. The trauma and occlusion of the carotid artery can lead to carotid artery dissections and strokelike symptoms. These stroke symptoms may be permanent (eg, speech difficulty, gait difficulties, swallowing difficulties) if the brain is unable to be reperfused in that area. Global hypoxia can lead to traumatic brain injury (TBI), resulting in cognitive difficulties, decision-making disabilities, and personality/behavior disorders. [19, 20, 21, 22, 23]
For patients who have attempted hanging or have had prolonged strangulation, prognosis is poor. These patients are usually unconscious on arrival and need advanced airway management to survive. These patients usually have hypoxic encephalopathy, cervical spinal cord injury, and serious respiratory compromise, leading to death. [24, 20, 22, 23]
Lab tests and imaging
As with any traumatic injury, begin with an evaluation of the patient’s airway, breathing, and circulation. Immediate resuscitation should take priority over imaging. After the patient is stabilized, laboratory studies may include complete blood count (CBC), CMP, coagulation studies, beta-HCG, toxicology panel (alcohol, drug, aspirin, and acetaminophen levels), lactic acid, and arterial blood gasses. Laboratory tests should not be drawn until after the airway has been assessed and, if necessary, secured. Arterial blood gas (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. [8]
CT is the first imaging modality for strangulation injuries, and CT angiography is the gold standard for imaging of the carotid and vertebral arteries, allowing evaluation of vascular and bony structures. Noncontrast CT is used to evaluate the brain for signs of stroke and cerebral edema. MRI is the most accurate study to evaluate soft tissues of the neck. MRI and MRA of the brain has the greatest sensitivity for evaluating global and anoxic brain injury, ischemic stroke, and, intracranial hemorrhage.
A cervical collar or other immobilization device should be immediately applied In any patients who have extensive cervical injury findings.
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.
Given the varied injuries associated with hanging and strangulation and the superiority of CT over plain films in the evaluation of the cervical spine, [15, 25] 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. [26, 7, 27, 28]
Postmortem CT (PMCT) is used to identify fractures after hanging and strangulation. Decker et al noted that although PMCT may not detect soft-tissue injuries in decomposed remains or subtle internal hemorrhages in neck injury, it is able to detect bony injuries as well as autopsy and might surpass autopsy in detecting subtle fractures. [29]
MRI has been shown on autopsy to successfully detect soft-tissue lesions in relation to strangulation and can serve as an alternative method or provide additional value to autopsy. Deininger-Czermak et al noted that MRI showed a high efficiency in verifying intramuscular hemorrhages that were confirmed on autopsy. [30, 31]
In a systematic review by Gascho et al, when compared to autopsy, CT demonstrated equivalent results regarding detection of fractures (mainly fractures of the hyoid bone or thyroid cartilage were investigated). They noted that the gas-bubble sign (gas bubbles in the tissue adjacent to the laryngeal structures when fractures were present) may even facilitate the detection of laryngeal fractures on CT. For detection of hemorrhages in the soft tissue of the neck, postmortem MRI was found to be more suitable for the detection of the gas-bubble sign in cases of strangulation. [32]
In an extensive study by Schulze et al, the gas-bubble sign regarding laryngeal fractures in postmortem hanging victims had a sensitivity of 79.2%, a positive predictive value of 95%, a specificity of 90.9%, a negative predictive value of 34.5%, and an accuracy of 83%. [27]
Management
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. [8, 33]
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. [19, 33, 17, 21]
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.
A cervical collar or other immobilization device should be immediately applied In any patients who have extensive cervical injury findings.
