Strangulation Injuries – Causes, Symptoms, Treatment

Pathophysiology

The underlying cause of strangulation morbidity and mortality is cerebral hypoxemia? and death. However, anatomic neck structures must be fully understood to evaluate the complex mechanisms of injuries in strangulation. Each structure has different weight capacities it can withstand before the collapse. Cervical? spine fractures most often result in complete hangings where the patient is dropped from a significant height. As previously stated, this height is usually greater than or equal to the patient’s height. Fracture? of the second cervical vertebrae?, otherwise known as the “hangman’s fracture,” leads to internal decapitation and immediate death. This pathologic result of hanging injury is less common than when compared to injuries which cause damage to other vital structures.

There are numerous anatomic neck structures that, when collapsed, can cause morbidity and mortality in hanging injuries. Jugular veins? collapse under 4.4 pounds of pressure. Carotid arteries? collapse under 5.5 to 22 pounds of pressure. The vertebral arteries will collapse under 18 to 66 pounds of pressure. The trachea? will collapse under 33 pounds of pressure. The cricoid cartilage? will fracture under 45 pounds of pressure. The collapse of each of these vital structures can lead to immediate death, as well as delayed complications. Damages to both anterior and posterior ligaments? and cervical spine dislocations have been documented as a result of strangulation injuries. Direct spinal cord? injury, hematoma, or hemorrhage can both cause immediate death and paralysis?.

Acute? death will ensue when compression or occlusion of the trachea occurs. In the past, this was proposed as the mechanism of mortality in most strangulation injuries. Swelling? to the airway and surrounding structures may also lead to acute or delayed death. Death has been documented up to 36 hours after initial strangulation injuries. Compromise to vascular structures has been proven to cause significant morbidity and mortality. This has been proven in tracheostomy patients who have committed suicide. Death in these cases did not involve compression of the trachea or airway due to the presence of an intact tracheostomy.

Compression of the jugular veins results in acute death by causing cerebral hypoxia? followed by loss of muscle tone. Once muscle tone is compromised, increased pressure is applied to both the carotid arteries and trachea. Direct compression of the carotid arteries also leads to decrease or loss of cerebral blood flow and brain death. Direct pressure on the carotid sinuses? causes a systemic? drop in blood pressure, bradycardia?, and other arrhythmias. Consequences are anoxic and hypoxic brain injury death.

Many of the martial arts “submission holds” are known to place direct pressure to these vascular structures primarily and can result in strangulation injuries. There can be long-term consequences of strangulation injuries due to vascular compromise as well. Long-term anoxic brain injury, thrombotic stroke?, dissection, and aneurysm of vessels can all cause significant morbidity.

Causes of Strangulation Injuries

Strangulation is defined as the compression of blood or air-filled structures which impedes circulation or function. In this summary, strangulation will refer to compression of anatomical neck structures leading to asphyxia and neuronal death. Strangulation injuries can be divided into several categories. These include hanging injuries, manual strangulation, and ligature injuries.[rx][rx][rx][rx]

Hanging injuries can be divided further into specific categories. Complete hanging is defined by the full weight of the patient being suspended by the neck. Incomplete hanging injuries encompass all injuries in which the patient is supported partially by another object such as the ground or furniture. For centuries hanging has been used in the penal systems as a form of punishment. The term “well-hung” referred to the erection a male experienced after a proper hanging was performed. This method of execution usually involved dropping the person from a height equal to or greater than their height, and this often resulted in spinal fractures, spinal trauma?, and spinal shock? resulting in priapism.

Ligature and manual strangulation injuries occur when a force that is independent of the patient’s body is applied to the neck. Strangulation injuries can also be divided into categories of intent. These include homicidal, suicidal, accidental, and auto-erotic.[rx][rx]

Diagnosis? of Strangulation Injuries

History and Physical

The history of a strangulation injury may be obtained from the patient, witnesses, family or friends, first responder personnel, or a combination of the above. Proper history will facilitate proper management. If possible, determine whether the strangulation was a manual, ligature, or hanging injury. Incomplete versus complete hanging injuries should also be differentiated. If the injury is a complete hanging, the height of drop should be assessed. Associated injuries and ingestion need to be evaluated. Obtaining approximate time of injury is also essential. The patient’s initial on-scene presentation, resuscitative efforts initiated, and patient stability or decompensation en route will also aid the practitioner to initiate proper management.

Physical examination may include one or more of the following “hard signs” of strangulation:

Head, Eyes, Ears, Nose, and Throat?

• Visual disturbances
• Conjunctival or facial petechial hemorrhages
• Swollen tongue or oropharynx
• Foreign body (blood, vomit, tissue) in oropharynx
• Facial edema?, lacerations, abrasions, ecchymosis
• Neck abrasions, edema, lacerations or ligature marks
• Tenderness? to palpation over 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

Evaluation

Once the patient is stabilized, laboratory and radiologic studies can aid in determining the severity of the injury. Laboratory studies may include complete blood count (CBC), CMP, coagulation studies, BHcg, toxicology panel (alcohol, drug, aspirin, and Tylenol levels), lactic acid, and ABG. CT is widely available and is the first line of radiologic evaluation of strangulation injuries. CT Angiogram of the carotid and vertebral arteries is the gold standard in care. This allows for evaluation of vascular and bony structures.

CT of the neck with contrast is less specific than CT Angiogram but will evaluate bony structures and vascular structures to a degree. Non-contrast CT of the brain will evaluate for stroke but is more sensitive for intracranial hemorrhage than for smaller ischemic strokes. Non-contrast CT scan of the brain will identify large areas of the infarct.

MRA of the neck is another imaging modality option, although it is less available in smaller and rural centers, and it is also more time-consuming than CT to complete. It is also less sensitive than CTA of the neck in evaluating vessels. MRI of the neck poses similar availability issues. It has less sensitivity than CTA in evaluating vascular structures; however, it is the most accurate study to evaluate soft tissues of the neck. MRI/MRA of the brain is the most sensitive modality in evaluating both global and anoxic brain injury, ischemic stroke and, intracranial hemorrhage.

Carotid doppler is not recommended for evaluation of strangulation injuries due to its inability to completely evaluate all of the possibly affected vascular structures. Plain chest radiography is also recommended in patients who have required intubation or are in respiratory distress.

Treatment of Strangulation Injuries

The primary survey, as in any traumatic injury, should begin with an evaluation of the patient’s airway, breathing, and circulation. Immediate resuscitative interventions should take priority over radiologic studies. If none of the “hard signs” are present, radiologic studies are not always necessary. After evaluation in the emergency department, the patient may be discharged with strict return precautions. If the patient presents with any of the “hard signs” of strangulation injury, laboratory and radiologic evaluation must be performed.[rx][rx]

If the radiologic studies are completely negative, disposition should be based on the patient’s clinical condition. Asymptomatic patients may be discharged after Emergency Department evaluation with strict return precautions and in-home monitoring by family or friends. Symptomatic patients with normal radiologic studies should either be admitted to the hospital or the emergency department observation unit, if available, for further monitoring.

References