Traumatic Eagle’s Syndrome: A Rare Cause of Neck Pain and Headache in Trauma Patients

Background

The length of the styloid process in most individuals ranges from 2 to 3 cm [1]. The presence of a styloid process longer than 3 cm is a rare finding, with an incidence of about 4% in the general population. Among individuals with an elongated styloid process, most are asymptomatic, and only about 4% exhibit the array of symptoms that clinically indicate Eagle Syndrome [2]. These symptoms are most commonly unilateral; however, bilateral presentation can also occur [3–5]. Patients can present with a variety of symptoms that are related to compression of the adjacent anatomical structures [4,5]. These include pain in the neck, jaw, and/or pharyngeal structures (eg, tongue, back of throat); odynophagia; abnormal sensations in the throat; and, importantly, symptoms from vascular injury (eg, stroke, transient ischemic attack, carotid dissection) [6]. Eagle syndrome can also be detected incidentally in the setting of trauma when patients undergo routine imaging of the head and/or cervical spine [7–9]. In these circumstances, vigilant monitoring of cerebrovascular symptoms and the acquisition of pertinent vascular imaging are imperative when there exists a substantial suspicion of vascular injury. Herein, we describe a case of a young man who was involved in a motor vehicle accident and subsequently experienced persistent neck pain. Elongated styloid processes were then identified on computed tomography (CT) imaging of the head and neck, originally obtained for evaluation of spine and brain injuries. We also reviewed the literature related to Eagle syndrome with bilaterally elongated styloid processes in the context of trauma.

Case Report

A 20-year-old man came to the Emergency Department after a motor vehicle collision. The patient was the restrained driver, when the vehicle’s brakes malfunctioned, resulting in a collision with a truck on the driver’s side. The patient was immediately extricated and placed in a cervical collar. He did not lose consciousness. The patient had pain in the left clavicle in association with unilateral left-sided neck pain. On physical examination, mild skin abrasions on the forehead and posterior right ear were noted. His past medical history was unremarkable. The ethanol blood level was 99 mg/dL (reference range, <20 mg/dL). There was a tenderness near the insertion of the sternocleidomastoid on the left clavicle medially, causing limited range of motion at the cervical spine. The patient was admitted for overnight observation due to persistent neck pain and headache that were unresponsive to analgesics and muscle relaxants. The patient described the pain as non-radiating and throbbing/aching in nature. There was no evidence of trismus. He denied dizziness, nausea, vomiting, dysphagia, tinnitus, or vision changes. A CT scan of the head, cervical spine, chest, abdomen, and pelvis was obtained and showed no acute injuries. However, elongated styloid processes measuring 3.34 cm on the left and 3.54 cm on the right were appreciated on cervical and head CT imaging (Figure 1). Consequently, CT angiogram of the neck with contrast was obtained but revealed no vascular injuries (Figure 2). A diagnosis of Eagle syndrome was made, and the patient was treated conservatively with analgesics and muscle relaxants. He was then discharged home the following day after resolution of his symptoms. At the 2-week follow-up visit, the patient remained free of symptoms.

Discussion

Eagle syndrome, the symptoms and signs caused by elongated styloid process(es) and/or a calcified styloid ligament, is a rare condition. Nonetheless, its clinical significance can be substantial. Eagle syndrome occurs at an incidence of approximately 0.16%, with a female to male ratio of 3: 1, and its typical age of onset is over 30 years [2]. Although elongation of both styloid processes is characteristic, symptoms are classically unilateral [3], as seen in our case. The average length of styloid process in the general population is approximately 2.5 cm. A styloid process greater than 3 cm is typically considered elongated and can cause Eagle syndrome [10]. The anatomical course and length of the styloid process plays a role in producing symptoms. An elongated styloid process can lead to compression of cranial nerves, resulting in throat and neck pain. In addition, an elongated styloid process poses a risk to the carotid arteries due to its proximity to these vascular structures in the neck. This could lead to carotid dissection, subsequently causing symptoms of stroke or transient ischemic attack [6]. In the present case, the patient had bilateral elongation of the styloid processes (right, 3.54 cm and left, 3.34 cm) in association with persistent, throbbing unilateral neck pain.

A recent systematic review evaluated the correlation between the onset of Eagle syndrome and traumatic events [3]. The authors found that most included studies reported concomitant trauma that triggered the onset of symptoms. We believe that trauma can lead to transient dislocation and/or fracture of the elongated styloid process, which result in compression of already stretched adjacent structures. Even mild injury can cause irritation of the well-innervated structures in the region (eg, carotid sheath, cervical fascia). Our patient was involved in a motor vehicle accident that triggered the patient symptoms, in particular the left neck pain. At one point in its anatomical course, the styloid process becomes surrounded by parapharyngeal space anteriorly and carotid sheath and its contents posteriorly (Figure 1B). In traumatic injuries, the elongated styloid process can be displaced and penetrate these structures, causing the classic symptoms of Eagle syndrome (eg, neck pain, abnormal swallowing, or foreign body sensation in the throat) [11]. Rarely, Eagle syndrome can occur after invasive dental procedures, such as tooth extraction [12]. Therefore, in addition to physicians, dentists should bear this diagnosis in mind when orofacial symptoms and headache cannot be explained by common etiologies, especially if styloid processes or calcified stylohyoid ligaments are readily visualized near the mandibular angle on panoramic radiographs. Additionally, although elongation of the styloid process is rare before adolescence, Eagle syndrome has been previously identified in pediatric patients. This indicates that it is important to maintain Eagle syndrome on the differential diagnosis in any age group [13].

Cases of post-traumatic Eagle syndrome with bilateral elongation of the styloid processes have been infrequently reported in the literature [7–9]. Saccomanno et al showed that remodeling of the elongated styloid process as well as the stylohyoid ligament plays a role in producing symptoms of Eagle syndrome in the long term [11]. The healing process typically involves inflammatory changes and, sometimes, granulation tissue; the presence of which in an anatomically crowded area such as the neck can place surrounding structures at risk for compression and irritation [5,14].

Eagle syndrome should be included in the differential diagnosis of neck pain, headache, or oropharyngeal symptoms after traumatic events, particularly to the head and neck. Other possible etiologies for these classic symptoms include temporomandibular joint disorder, trigeminal neuralgia, cervical degenerative disease, migraine headaches, and temporal arteritis [5,11,14].

Features that favor Eagle syndrome as the cause of neck pain can include sudden-onset sharp or throbbing pain in the neck and/or throat; less diffuse pain with localization to one side (unless bilateral); tinnitus; and orofacial pain (particularly in ear or jaw, and pain with chewing) [5,7,14]. This is attributed to the proximity of the elongated styloid process from the vagus, glossopharyngeal, and facial nerves. Along with the presence of such symptoms, history of trauma should prompt the evaluation for possible Eagle syndrome, which can be easily detected on imaging routinely performed in trauma patients, including CT scan of the head and neck, although plain radio-graphs may be sufficient for diagnosis. In the present case, the patient had persistent throbbing neck pain and headache localized to the left side that were not relieved by simple analgesics or muscle relaxants, prompting overnight monitoring and further imaging. Our patient’s symptoms along with the presence of elongated styoloid processes on imaging makes Eagle syndrome a more likely etiology.

Many patients with elongated styloid processes are asymptomatic. Traumatic events, as seen in our case, can induce the onset of Eagle syndrome, and an attempt at conservative management can be made. This usually includes analgesics (eg, nonsteroidal anti-inflammatory drugs, acetaminophen), muscle relaxants, anticonvulsants, and local steroid injections [15]. Surgical intervention may be needed in refractory cases with persistent or worsening symptoms, and it is often quite effective, with resolution of symptoms in 80% of patients [3]. Surgery is also required when there is evidence of vascular injury or significant compression of nearby structures and is considered the definitive treatment.

Conclusions

Eagle syndrome is a rare condition but it can cause significant morbidity due to involvement of vital structures in the neck, such as the carotid arteries. Traumatic events (eg, motor vehicle accidents) can trigger the onset of Eagle syndrome due to displacement of the elongated styloid processes and subsequent injury of adjacent structures. Early detection of this syndrome, especially in trauma patients, can prevent futile attempts of treatment and can enable early intervention alternatives.