Strangulation Injuries

Etiology

Strangulation is defined as the compression of blood- or air-filled structures, impeding circulation or function. In this activity, strangulation refers specifically to the compression of anatomical neck structures, leading to asphyxia and neuronal death. Strangulation injuries are categorized into hanging injuries, manual strangulation, and ligature injuries.[9][10][11][12]

Hanging injuries are further classified based on suspension. Complete hanging occurs when the neck supports the patient's full weight. Incomplete hanging involves partial support from another object, such as the ground or furniture. Hanging has been used as a method of execution for centuries. The phrase “well-hung” historically referred to the erection observed in male individuals after a properly performed hanging. This execution method typically involved a drop equal to or greater than the person’s height, often resulting in spinal fractures, spinal trauma, and spinal shock, which could cause priapism.[13] Hanging injuries are also associated with vascular pathology, ranging from carotid intimal tears to complete rupture.[14]

Ligature and manual strangulation injuries occur when an external force, independent of the patient’s body weight, is applied to the neck. Strangulation injuries may also be classified by intent, including homicidal, suicidal, accidental, and autoerotic.[15] The material used in ligature or hanging injuries may also influence pathology and forensic findings.[16]

A significant number of pediatric strangulation injuries are accidental. Behavioral characteristics unique to different age groups influence the mechanisms behind these injuries and fatalities. Younger children may sustain injuries from car windows, electrical cords, or entrapment between furniture, including high chairs.[17][18] Accidental or intentional suffocation injuries, which differ from strangulation by causing asphyxia through oral-nasal obstruction, may also be present. Although rare, playground and handlebar strangulation injuries are important considerations in pediatric polytrauma cases with supporting histories.[19]

As mentioned, social media influences play an increasingly critical role in teenage and adolescent populations. The literature describes autoerotic asphyxiation as a more common mechanism in this group, representing both an intentional and accidental cause of injury.

Strangulation injuries can occur during partnered sexual activity, either intentionally, accidentally, or both. This mechanism is a dangerous form of intimate partner violence, with survivors facing a high risk of becoming victims of homicide.[20] Conversely, consenting adults engaging in low-force activity for pleasure may suffer severe injuries if precautions are not taken. Additionally, autoerotic asphyxiation is recognized as a form of paraphilia and is seen in adult strangulation cases.[21]

Many submission holds in martial arts exert direct pressure on cervical structures, posing a risk for strangulation injuries. Similarly, law enforcement and military personnel are trained in "vascular neck restraint," a controversial but effective method of subduing a target. Improper application of this technique can lead to permanent, debilitating injuries or death.[22]

Epidemiology

The true prevalence and incidence of all-cause strangulation injuries and related mortality are unknown. Due to the wide range of etiologies leading to a common injury pathway, epidemiological studies and case series in the literature are typically specific to particular causes and populations.

Hanging injuries are the 2nd most common method of suicide in the United States, with gunshot wounds being the leading cause. Male individuals are more likely to die by suicide using either of these methods.[23] Women in abusive relationships face the highest risk of strangulation injury. Epidemiological studies and medical literature may underestimate the true incidence and prevalence, as many patients underreport these injuries when seeking medical care. The incidence of hanging injuries has risen in the United States in recent years, though their role in homicide cases remained relatively stable from 2006 to 2013. The increasing popularity of “choking games” among preteens and teenagers has also contributed to the rise in these injuries.[24]

In a retrospective case series published by Berke et al (2019), 98 near-hanging patients were identified over a period of 11 years. All patients underwent trauma evaluation, and 254 computed tomography (CT) and magnetic resonance imaging (MRI) scans were performed, identifying only 8 traumatic injuries. Two patients had injuries to the cervical vasculature, 3 had thyroid cartilage and hyoid bone fractures, and 3 had vertebral injuries. A total of 35.7% of patients had clinically diagnosed anoxic brain injury, which was present in all 19 patients who died (19.5%). Injuries were more common in patients with a low Glasgow Coma Scale score compared with those exhibiting a normal score.[25]

In pediatric patients younger than 1 year, unintentional strangulation injuries rank 4th among all causes of unintentional injury. Motor vehicle accidents, drownings, and burns are more common. Of more than 200,000 playground injuries recorded in 1999, only 0.07% were fatal, and 50% of these fatalities were caused by asphyxia from strangulation injuries. Around 80% of victims were younger than 10 years.

Pathophysiology

The common pathway through which strangulation injuries cause morbidity and mortality is cerebral hypoxemia, leading to cerebral ischemia. Four specific mechanisms are described in the literature.

First, external pressure on the jugular veins impedes venous return from the cerebral circulation, creating backpressure that restricts arterial inflow and raises intracranial pressure. This progression results in unconsciousness, brainstem dysfunction, asphyxia, and, ultimately, death. Second, direct compression of the carotid arteries obstructs oxygenated blood flow to the brain, similarly causing asphyxia and death. Third, obstruction of the larynx prevents oxygenation of the pulmonary vasculature, leading to systemic hypoxia. The most pronounced effects include rapid loss of consciousness followed by death. Fourth, although rare, bilateral pressure on the carotid bodies can trigger cardiac dysrhythmias, potentially causing cardiac arrest and death if not promptly recognized.[26]

Acute consequences of impaired cerebral perfusion include various forms of anoxic brain injury. Patients with chronic cerebrovascular disease may develop watershed infarcts. Severe initial injuries can lead to diffuse cerebral edema, increasing the risk of brain herniation and death. Diffuse axonal injury has also been documented in autopsy reports.

Pathophysiologic mechanisms can be categorized according to the 3 main types of strangulation. These types include hanging, manual strangulation, and ligature-based injuries.

The nature of a hanging injury determines its pathophysiology. Judicial hangings from height can result in rapid deceleration forces. These mechanical forces may cause “internal decapitation,” which includes spinal cord transection, cervical vascular transection, and various spinal fractures. The classic "hangman's fracture" occurs when deceleration leads to forceful neck extension, resulting in bilateral C2 pedicle fractures. Severe forces can cause significant subluxation of C2 from C3, endangering the spinal cord. Associated hematomas may also contribute to neurological compromise. Similar hyperextension injuries have been described in motor vehicle accidents where the top of the steering wheel abruptly halts forward neck movement in the absence of an airbag.

Manual strangulation or hangings without a significant height drop involve less deceleration force, making fractures uncommon in these cases. However, many cervical spine injuries in these patients are classified as unstable.[27] Compression of the jugular veins rapidly leads to cerebral hypoxia and subsequent loss of muscle tone. As muscle tone diminishes, pressure on the carotid arteries and trachea increases. Direct compression of the carotid arteries further reduces cerebral blood flow, resulting in brain death. Pressure on the carotid sinuses can also trigger a systemic blood pressure drop and arrhythmias, including bradycardia, ultimately leading to anoxic and hypoxic brain injury and death.

Ligature-based injuries can involve focused force trauma to specific structures. Force applied over a smaller surface area may produce more localized injuries rather than extensive crush-type damage. The type of ligature also plays a role. Barbed ligatures, for example, can cause penetrating trauma to different neck zones and may even damage deeper structures. All types of aerodigestive injuries must be considered in these patients. Fractures of the hyoid bone and thyroid cartilage often result from direct force applied to these structures.

Strangulation injuries are associated with various forms of spinal cord trauma, with pathophysiology directly linked to the specific mechanism. Complete spinal cord transection may indicate a rapid deceleration injury, whereas damage to surrounding structures can threaten nearby neurological anatomy. Hematomas and injury-related edema have been described as contributing to spinal cord trauma. Additionally, spinal cord ischemia may occur due to the disruption of vessels responsible for maintaining perfusion. Evaluation requires careful consideration, as mechanical forces and displaced structures may compromise spinal tendons and ligaments. These injuries are diverse in their presentation, and severe cases can lead to paralysis and, ultimately, death.

Facial and cervical petechiae, along with ecchymoses, are common injury patterns in strangulation cases. The pressure exerted on compressed vasculature can lead to capillary, venule, and arteriole injuries, producing these characteristic skin findings. Externally applied force may also cause facial plethora or swelling. Similar mechanisms contribute to ocular manifestations, such as subconjunctival hemorrhages. Epistaxis has also been reported and is believed to result from pressure-induced vascular injury.

Vascular trauma in strangulation injuries can range from intimal tears to complete vessel transection. These injuries may lead to long-term complications, including vascular abnormalities such as pseudoaneurysms. Lower pressures are sufficient to occlude cervical veins, whereas higher pressures are required to deform or injure cervical arteries. Thrombotic events may occur, potentially resulting in acute occlusion or embolic complications.[28]

Histopathology

The histopathological implications of strangulation injuries are as varied as the underlying pathophysiology and the conditions present at the time of injury. Anoxic brain injury is a typical finding, with cell damage becoming evident within as little as 4 hours, depending on the extent and duration of anoxia or hypoxia. Ischemic injury may lead to primary necrosis of neurological structures or delayed cell death via apoptosis in patients who survive the initial insult. A "cloudy swelling" pattern in nuclear regions and a reduction in nuclear basophilia have been described. Cytoplasmic shrinkage and pyknotic nuclei are also observed. The presence of classic “red neurons” becomes apparent by 8 to 12 hours.

The brain regions most susceptible to strangulation injuries correspond to areas with higher metabolic rates and oxygen demands. Watershed regions are particularly vulnerable. CA1 pyramidal neurons within the hippocampus are associated with memory deficits observed in survivors. In the cerebellum, Purkinje cells are at higher risk of anoxic injury, which may contribute to gait abnormalities. Arterial border zones throughout the brain can exhibit “wedge-shaped” lesions, which may also be detected on detailed neuroimaging.[29]

Forensic pathology considerations in strangulation cases are numerous. Excoriation marks on the face and various body surfaces may indicate a struggle, either as the patient attempts to remove a ligature or another object causing strangulation or as a result of an assailant’s actions. Burns and musculoskeletal trauma may also be present on autopsy, depending on the circumstances. Determining the exact cause of death can be challenging due to the multiple pathways that converge in the common pathophysiology of death from strangulation. For example, homicide victims who sustain strangulation injuries and are subsequently found submerged in water may exhibit signs of both strangulation and drowning. Since both mechanisms lead to hypoxia and, ultimately, death, establishing the precise sequence of events can be difficult.

Toxicokinetics

Strangulation injuries, whether accidental or intentional, may be further complicated by toxicological factors. Alcohol, prescription medications, and nonprescription drugs are often ingested around the time of injury. Many of these substances can cause central nervous system depression and contribute to altered mental status. Additionally, life-threatening overdoses involving medications such as acetaminophen, aspirin, and tricyclic antidepressants can lead to severe metabolic disturbances, further complicating the clinical presentation and management of strangulation injuries.

History and Physical

A history of strangulation injury may be obtained from the patient, witnesses, family members, friends, or 1st responders. A thorough history guides appropriate evaluation and treatment. If possible, an assessment should be made to determine whether the strangulation was manual, ligature-based, or a hanging injury. The type of material used for ligature or hanging injuries should be clarified. A distinction should be made between incomplete and complete hanging injuries, as the height of the drop in complete hangings may provide prognostic information. Associated injuries and substance ingestion should also be assessed.

Establishing the approximate time of injury and the duration of strangulation is essential. Additionally, details regarding the patient’s initial on-scene presentation, resuscitative efforts, and any deterioration during transport can further inform clinical decision-making.

The physical examination may reveal one or more “hard signs” of strangulation, evident when examining the following organ systems:

• Head, eyes, ears, nose, and throat
  • Visual disturbances
  • Conjunctival or facial petechial hemorrhages
  • Swollen tongue or oropharynx
  • Foreign body (eg, blood, vomit, tissue) in the oropharynx
  • Facial edema, lacerations, abrasions, ecchymosis
  • Neck abrasions, edema, lacerations, or ligature marks
  • Tenderness to palpation over the larynx
  • Hoarseness or stridor
  • Subcutaneous edema or crepitus
• Cardiovascular
  • Cyanosis or hypoxia
  • Arrhythmias
  • Respiratory distress
  • Crackles or wheezes
  • Cough
• Neurologic
  • Altered mental status
  • Seizures
  • Stroke-like symptoms
  • Incontinence

As with all traumatic injuries, the physical examination should begin with an assessment of the airway. Foreign bodies, blood, vomitus, or sputum may be present. An audible stridor may indicate a compromised upper airway. Auscultation of cervical structures is useful not only for evaluating airway patency but also for detecting signs of vascular injury, including bruits and thrills.

The patient’s breathing pattern should be observed. Further investigation of abnormal respiratory patterns like bradypnea may reveal the Cushing triad in cases of critically elevated intracranial pressure. Evaluating the patient’s circulatory status is essential. Blood pressure monitoring, capillary refill, and extremity warmth can help determine whether spinal shock is present.[30]

A thorough neurological assessment is also crucial. Muscle tone, reflexes, and various eponymous signs may indicate upper motor neuron or cerebrovascular injury. Lateralizing signs should be carefully evaluated, as they may assist in localizing spinal cord lesions.

Skin and musculoskeletal findings often accompany severe injuries. A comprehensive head-to-toe assessment should be conducted based on the nature of the trauma. In polytrauma patients, additional injuries may go unnoticed if attention remains solely on the immediate consequences of the strangulation injury.

A rapid psychiatric assessment is essential when appropriate. Signs of depression, such as low mood, suicidal ideation, and altered thought content, may be evident. Evaluating cognitive functions, including sensorium, concentration, and memory, can help identify concurrent intoxication or concussive head injury.

Evaluation

Once the patient is stabilized, laboratory and radiologic studies help assess the severity of the injury. Laboratory tests may include a complete blood count, comprehensive metabolic panel, coagulation studies, β-human chorionic gonadotropin, toxicology screening (including alcohol, drug, aspirin, and acetaminophen levels), lactic acid, and arterial blood gases.

CT is widely available and is the 1st-line imaging modality for strangulation injuries. CT angiography (CTA) of the carotid and vertebral arteries is the gold standard, providing a detailed evaluation of vascular and bony structures. Contrast-enhanced CT of the neck offers less specificity than CTA but still allows for some assessment of both vascular and bony structures.

Noncontrast-enhanced brain CT is useful for detecting intracranial hemorrhage and may identify large areas of infarcted tissue. However, this modality is less sensitive for smaller ischemic strokes. In acutely presenting patients, noncontrast-enhanced CT is the preferred study for detecting cerebral edema.[31]

Magnetic resonance angiography (MRA) of the neck is another imaging option, though it is less available in smaller and rural centers and requires more time to complete than CT. MRA is also less sensitive than CTA for evaluating vascular structures. MRI of the neck faces similar availability challenges. However, while less sensitive than CT for vascular assessment, MRI provides the most accurate evaluation of soft tissue injuries.

Brain MRI or MRA is the most sensitive modality for detecting global and anoxic brain injury, ischemic stroke, and intracranial hemorrhage. However, the patient’s clinical stability must be considered before proceeding with these studies.

Carotid Doppler is not recommended for evaluating strangulation injuries due to its inability to fully assess affected vascular structures. Plain chest radiography is recommended for patients requiring intubation or experiencing respiratory distress. Bronchoscopy and upper gastrointestinal endoscopy may be warranted later in the patient’s care when signs of aerodigestive injury, such as hemoptysis or hematemesis, are present.[32]

Treatment / Management

The primary survey in any traumatic injury should begin with an evaluation of airway, breathing, and circulation. Immediate resuscitative interventions take precedence over radiologic studies. Clinicians responsible for the acute management of strangulation injuries must have extensive airway management experience, including proficiency in surgical techniques such as emergent tracheostomy and cricothyrotomy.

Patients exhibiting hard signs or other indications of extensive cervical injury should have an immobilization device, such as a cervical collar, applied immediately. Removal should only occur after clinical and radiographic evaluation has ruled out critical pathology, including unstable fractures and vascular injury. If no hard signs are present, radiologic studies may not be necessary. After assessment in the emergency department, patients without concerning findings may be discharged with strict return precautions. However, individuals with hard signs of strangulation injury require laboratory and radiologic evaluation.[33]

If radiologic studies yield entirely negative results, disposition should be guided by the patient’s clinical condition. Asymptomatic patients may be discharged following an emergency department evaluation, provided they have strict return precautions and are monitored in-home by family or friends. Symptomatic patients with normal imaging should be admitted either to the hospital or, if available, to an emergency department observation unit for continued monitoring.

Admitted patients require an interprofessional approach tailored to the extent of their injuries. Delayed pulmonary edema and complications from concomitant musculoskeletal trauma may become significant concerns, necessitating specialty and organ-specific care.[34] Management of confirmed blunt cerebrovascular injury typically includes antiplatelet therapy.[35](B3)

Differential Diagnosis

The differential diagnosis of strangulation injuries includes the following:

• Anaphylactic reaction
• Angioneurotic edema
• Bronchial asthma
• Chronic obstructive pulmonary disease
• Depressive disorders and suicidal behavior
• Intimate partner violence
• Acute epiglottitis
• Traumatic injuries of the neck
• Sexual violence
• Traumatic spinal cord injuries

A thorough differential diagnosis ensures that clinicians consider alternative or coexisting conditions that may mimic or complicate strangulation injuries, guiding appropriate diagnostic testing and timely interventions. Recognizing these conditions allows for targeted treatments, reducing morbidity and improving patient outcomes.

Prognosis

The prognosis for patients without significant external injuries and with unremarkable radiologic findings is generally favorable. Although delayed vascular complications remain a concern, imaging advancements have made these cases uncommon. Psychosocial factors become the primary consideration for these individuals, with prognosis depending on reducing exposure to further harm.

Severely injured patients, particularly those with significant neurological impairment, face a much poorer prognosis. Outcomes are largely determined by the severity and duration of anoxic brain injury, with long-term recovery depending on the specific brain regions affected. While a low Glasgow Coma Scale score suggests a worse prognosis, some patients still achieve meaningful recovery. However, those presenting in cardiac arrest typically have a grave prognosis.

Complications

Strangulation injuries can lead to both immediate and delayed complications, including airway obstruction, vascular damage, and neurological deficits. Vascular injuries such as carotid or vertebral artery dissection may result in stroke, while delayed airway edema can cause respiratory distress hours after the initial event. Psychological consequences, including posttraumatic stress disorder and increased risk of self-harm, may also develop, necessitating long-term follow-up and interprofessional care.