Clinical History
The 58-year-old male patient who presented had been involved in a motor vehicle crash. An inspection of the oropharynx revealed a remarkable anterior bulging of the posterior pharyngeal wall with
reddish discoloration, which was extending downwards to the laryngopharynx.
Imaging Findings
The patient had been involved in a motor vehicle crash in which his car was struck from behind at 30 km/h. The victim, who had been wearing a seat belt, described a rear-end collision to the headrest
of the seat. It was obvious that he sustained a whiplash injury and he complained about mild neck pain. He was scored 15 in the Glasgow-coma-scale and was lacking focal neurological findings. His
medical history was unremarkable. Subcutaneous bruising over the neck and anterior chest was evident. There was no significant limitation of neck movement, but the patient complained about sore
throat, hoarseness, difficulty in swallowing and progressive dyspnoea. An inspection of the oropharynx revealed a remarkable anterior bulging of the posterior pharyngeal wall with reddish
discoloration, which was extending downwards to the laryngopharynx, causing a moderate degree of upper airway-obstruction, suggestive of a retropharyngeal hematoma. Laboratory studies were found to
be normal. A lateral radiograph of the neck showed no cervical fracture, but disclosed a widened prevertebral space. An emergency CT scan was obtained. The CT images showed a midline hypoattenuating
retropharyngeal collection anterior to the swollen prevertebral musculature, extending from the base of the skull to below the level of the glottis. The airway was displaced anteriorly at this level.
No osseous pathology was found. Conservative treatment was installed. The patient was monitored for 48 h. A two-day follow-up CT examination and a four-day follow-up MR examination demonstrated
progressive resorption of the hematoma. The patient recovered uneventfully and was discharged five days later.
Discussion
Whiplash injuries, commonly seen in automobile accidents with an estimated incidence of approximately 4 per 1000 persons, are associated to cervical spine trauma induced by ligamentous, osseous and
muscular disruption. Retropharyngeal hematoma induced by whiplash injury, without further pathology in the cervical spine, as in our patient, is rare and may lead to an unfavourable outcome in case
of progressive blood loss and upper airway obstruction. Bleeding in the retropharyngeal space, which represents a potential danger space, can be life-threatening due to the anatomical relations and
boundaries in this space, which are defined by fasciae and muscles that provide minor resistance to the expansion of the hematoma. As the retropharyngeal hematoma expands downwards, narrowing of the
airway can occur, resulting clinically in inspiratory stridor, hoarseness or even total airway obstruction. The mechanism of hemorrhage in the prevertebral space during whiplash injury is still
unclear. One of the most accepted theories implicates tearing of the longus colli muscles, along the vertebral bodies, during hyperextension at the cervico-thoracic junction. Another theory
implicates the avulsion of branches of the vertebral arteries during their course through the transverse foramina, while sustaining the shear forces of a rear end collision. We believe that in our
patient both mechanisms were responsible for the formation of the traumatic hematoma. As demonstrated, by the CT images, both the prevertebral space and the retropharyngeal space are affected by
pathology. The extent of the traumatic cervical hematoma of our patient from the level of C1 to the level of C6 is also compatible with the type of injury, namely the whiplash injury. The usual type
of whiplash injury induces, in the occupants of a bumped vehicle, sudden lower cervical spine extension with upper flexion, creating a non-physiological cervical S-curvature, responsible for shear
forces in the osseous, ligamental and muscular attachments of the cervical spine. The amplitude of cervical spine response is proportional to the shear forces. The vehicle collision generates major
forces which are transferred to the neck by an acceleration–deceleration mechanism (whiplash). Theoretically, every structure of the cervical spine could be damaged during a whiplash injury.
However, after studying the literature, only few references were found concerning traumatic retropharyngeal hematoma not associated to any other cervical spine injury or to coagulopathic states,
delineating the rarity of the injury. In our case, the CT and MRI have not revealed other injuries. The possibility of retropharyngeal hematomas, although rare, should be taken into account after
whiplash injury in all patients, regardless of lack of symptoms or other cervical injuries. An accurate and quick imaging approach is essential to avoid life-threatening conditions.
Differential Diagnosis List
Traumatic retropharyngeal and prevetrebral hematoma.
Final Diagnosis
Traumatic retropharyngeal and prevetrebral hematoma.