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Traumatic asphyxia, or Perthes's syndrome, is a medical emergency caused by an intense compression of the thoracic cavity, causing venous back-flow from the right side of the heart into the veins of the neck and the brain.

Causes
Traumatic asphyxia occurs when a powerful compressive force is applied to the chest or abdomen. This is most often seen in motor vehicle accidents, as well as industrial and farming accidents. However, it can be present anytime a significant pressure is applied to the chest and upper abdomen, such as someone being pinned underneath an object.

Pathophysiology
The sudden impact on the chest causes an increase in intrathoracic pressure. This results in blood being pushed from the right atrium backward towards the superior vena cava and jugular veins. Valves in these vessels are unable to withstand the increase in pressure from the back flow of blood.

In order for traumatic asphyxia to occur, a Valsalva maneuver is required when the traumatic force is met. Exhalation against the closed glottis along with the traumatic event causes air that cannot escape from the thoracic cavity. Instead, the air causes increased venous back-pressure, in which the blood is transferred back to the heart through the right atrium, to the superior vena cava, and to the head and neck veins and capillaries. This back flow of blood and stagnation can account for the development of characteristic petechiae, facial edema, and subconjunctival hemorrhage.

Signs and symptoms
While there is no exact standard or physical sign for diagnosing traumatic asphyxia, there are a number of ways that the condition manifests itself in a patient in which it can be diagnosed. First and foremost is radiographic imaging such as computed topography (CT) images of the chest, abdomen, pelvis, and brain of the patient; chest x-rays; bronchoscopies; and possibly chest ultrasonography; which all narrow the diagnoses for medical providers.

Secondly, one of the major considerations with traumatic asphyxia is going to be he mechanism of injury and how the patient presents to the hospital. For example, if a patient arrives to the hospital after some type of crush or compression injury to the thorax, traumatic asphyxia should be suspected and the proper steps such as radiographic imaging, blood work, etc. should be initiated by the medical team.

Patients with these types of crush injuries may also present with cyanosis, edema, and petechial hemorrhages across the head, neck, and upper chest. In addition to this, patients may have subconjunctival or retinal hemorrhages, shortness of breath, diminished to absent breath sounds, anxiety, severe thoracic pain, loss of consciousness, vision loss, exopthalmos, confusion, deviated trachea, and abdominal pain which could indicate spleen, liver, or gastrointestinal involvement.

In addition to these signs, the patient will also have increased levels of creatine phosphokinase (CK), lactic dehydrogenase (LDH), aspartate aminotransferase (AST), and alanine aminotransferase (ALT) that will assist the provider in diagnosing traumatic asphyxia. The blood arterial gasses of these types of patients may also show hypoxia and hypercapnia.

Diagnosis
Diagnosis of traumatic asphyxia is primarily based on clinical presentation. Patients are seen with a cyanotic discoloration of the shoulders, neck, and face, jugular distention, bulging of the eyeballs, and swelling of the tongue and lips. The swelling of tongue and lips are the result of edema, caused by excessive blood accumulating in the veins of the head and neck, as well as venous stasis.

Prognosis
For individuals who survive the initial crush injury, survival rates are high, with many returning to their pre-injury state within 12 months of trauma.