Abstract
Background
Eagle’s syndrome, also called stylohyoid complex syndrome, is a rare syndrome pathology characterised by latero-cervical pain radiating to the face, linked to an abnormal enlargement of the styloid or calcification of the stylo-hyoid ligament.
Case
We report here the case of a young man of 25 suffering from cluster headache resistant to treatments, revealing Eagle’s syndrome.
Conclusion
Only surgery led to a real improvement of his condition.
Introduction
We report here the case of a young man of 25 suffering from cluster headache resistant to treatments revealing Eagle’s syndrome.
Cluster headache (CH) is characterised by one-sided, short-lasting attacks of unbearable, periorbital pain accompanied by cranial autonomic symptoms and/or a sense of restlessness. Given the severity, CH can lead to profound personal, social and economic consequences .CH is divided into a chronic and an episodic phenotype, the first being characterised by periods of remission lasting less than 3 months over one year and the latter by attack-free periods lasting at least 3 months. The pathophysiology of CH is not fully elucidated, but imaging findings, the trigeminal distribution of pain and the fact that CH shows striking chronobiological features suggest that trigeminal-hypothalamic components are important.
Eagle’s syndrome, or stylohyoid complex syndrome, is a rare syndrome characterised by latero-cervical pain radiating to the face, pharyngeal pain increased by swallowing, linked to an abnormal enlargement of the styloid or calcification of the stylo-hyoid ligament. This creates an irritation phenomenon on neighbouring structures, namely the carotid vessels, the sympathetic nerve chain, the vagus and glossopharyngeal nerves and the facial nerve, which causes various pains.
Due to its location, multiple vascular complications are possible, in particular carotid dissection or thrombosis, but cluster headache has to our knowledge rarely been reported until our case.
Case
A young 25-year-old man without particular medical history was initially referred for presented left hemicranial headaches with neck pain for 6 months. Headaches were located regularly on the right First pain episodes started after a thrilling ride with high kinetics.
These headaches could last from 15 minutes to 180 minutes with conjunctival injection, nasal congestion, palpebral edema meeting the IHCD-3 (1) criteria of chronic cluster headache. Brain MRI without and with intravenous injection of gadolinium, the Willis polygon was normal. An oral treatment with verapamil extended release 240 mg twice daily was started. In seizure treatment, the patient receives sumatriptan injections and high flow oxygen. However, no free interval was observed and episode frequency kept increasing from multi-weekly to multi-daily. The pain became disabling for the activities of daily life and did not allow the patient to continue working.
The patient visited the emergency department with a headache that had persisted for 24 hours. On clinical examination, his pain was increased when he mobilised his neck (2). He had no dysphagia, no odynophagia, and no ear, nose, throat signs. The patient had neuro-vegetative signs (crying, conjunctival hyperhemia, heat) on both sides, and neck pain (3). Neck pain was reproduced on palpation and followed by paroxysmal peri-orbital pain. Signs were evolving by crisis with a permanent painful background.
Facing these atypical signs for a simple crisis of cluster headache: Duration of the crisis, neck pain, no free interval for 6 months, we decided to perform a CT scan of the neck with injection for supra-aortic trunks. The scan found (Figure 1) bilaterally elongated styloid processes also with ossification of the left stylo-hyoid ligament, with, on the left, a visualised contact with the external carotid artery. To summarise, the patient presented a pain provoked by head turning, ipsilateral to the inflamed stylohyoid ligament and there was a radiological evidence of elongated styloid process. The patient met the IHCD-3 (1) clinical and radiological criteria for headache or facial pain attributed to inflammation of the stylohyoid ligament, also known as Eagle’s syndrome.
Elongated styloid process coming into contact with the external carotid artery ((a) right, (b) left). Elongated styloid process (c) 46 mm right, (d) 52 mm left.
Analgesic injection through the tonsillary fossa was carried out with lidocaine by the oral maxillofacial surgeons and showed little success.
Faced with therapeutic resistance, it was decided jointly with the oral maxillofacial surgeons to carry out bilateral endo-oral surgery. Cluster headache and cervical pains showed a significant improvement after surgery. Six weeks after surgery, the patient went from three crises of cluster headache per day to one per week after surgery and verapamil treatment was stopped. The patient, however, developed daily persistent headaches in a context of past drug abuse.
Discussion
The usual length of the styloid process is 2 to 3 cm (4), a length greater than 3 cm is abnormal and found in 4% of the population and only 4–10% have symptoms.
Eagle’s syndrome (5) was first described in 1937 by Dr. Watts Weem Eagle (6), an ear-nose-throat specialist in North Carolina, following two cases of fairly atypical neck and laryngeal pain following tonsillectomies. Eagle established the link between these symptoms and the presence of an elongation of the styloid process visible on radiographs a few months after surgery. He concluded that the styloid process is stimulated post traumatically, leading to its elongation and the symptoms resulting therefrom.
Since then, several subtypes of Eagle syndrome have been described, the two main forms of which are the classical form and the carotid form (6).
The classic form is correlated with a tonsillectomy, pharyngeal surgery or a cervical trauma.
Patients describe earache, neck pain, shoulder pain, pain when turning the head, dysphagia, odynophagia, and sensation of an intrapharyngeal foreign body (7). This classic form of Eagle's syndrome is thought to be due to an anomaly in the length of the styloid or to ossification of the stylohyoid ligament, which would compress the neighboring cranial nerves (nerves V, VII, IX and X).
The carotid form would be due to the posterior angulation of the lower part of the elongated styloid. The latter would crush the internal or more often external carotid artery and would cause pain along the route of the artery. The crushing of the carotid vessels produces irritation of the sympathetic nerves, which explains the pain described. This anatomical location close to the autonomic nervous system may explain our patient cluster headache picture (7,8). The fact he presented increased crises with head rotation made us think of a mechanical compression of the trigeminal–autonomic nervous system pathway involved in cluster headaches.
Another complication, if the pressure is very strong, is that an interruption in blood flow can take place causing transient cerebral ischemia or even carotid dissection (8,9).
The diagnosis of Eagle’s syndrome is based on IHCD-3 (1) diagnostic criteria. Those criteria consist of any head, neck, pharyngeal and/or facial pain with at least two of the four following signs: Pain provoked or exacerbated by digital palpation of the stylohyoid ligament, pain provoked by head turning, pain improved by injection of local anaesthetic agent into the stylohyoid ligament, or by styloidectomy, or pain ipsilateral to the inflamed stylohyoid ligament. Also, there must be radiological evidence of a calcified or elongated stylohyoid ligament.
Steinman proposed in 1970 three hypotheses to explain this ossification: A reactive hyperplasia of the styloid process or stylohyoid ligament stimulated by a trauma, reactive metaplasia, also from a traumatic stimulus, or anatomical variance. Other hypotheses have been proposed, such as hormonal changes and genetic predisposition.
The frequency of Eagle’s syndrome is variable. According to Eagle, 4% of patients are found to have an elongated styloid process, of which 4% are symptomatic. This leads to a total of 0.16% of the general population. The authors agree that the average age of those with the symptoms is rather young, the lengthening of the styloid process is bilateral, but the symptoms are often unilateral. Women are more affected.
The differential diagnoses to be evoked are pathologies of the temporomandibular joint, dental pathologies, salivary lithiasis, or trigeminal neuralgia; it is sometimes very difficult to differentiate between these etiologies with similar symptomatology.
Two therapeutic options exist (10): A conservative option and a surgical option. The conservative option consists of taking non-steroidal anti-inflammatory drugs; sometimes tegretol can help the symptoms in the short term. In addition to the oral medication, analgesic injections through the tonsillary fossa can be carried out with lidocaine or steroids.
The other alternative is surgical with two routes, one intraoral and one extraoral. Whichever way is chosen, it is important to resect the styloid process from its temporal attachment and to resect both sides. The intraoral route (11) is generally privileged, presenting fewer risks: A tonsillectomy is carried out then the styloid process is resected from its temporal attachment. Risks of intra-oral surgery are mainly infections, vascular lesions, facial paralysis and trismus. Faced with disabling pain resistant to treatment, surgical treatment is encouraged although it does not allow headache to be resolved systematically (11). An improvement is reported in 90% of cases.
The criteria are not precisely defined but include the duration without pain and crisis.
Conclusion
Although very rare, it seems important for clinicians to know that Eagle’s syndrome can also be responsible for cluster headaches resistant to usual treatments with an atypical clinical presentation.
Clinical implications
This case report calls attention to Eagle’s syndrome, cluster headache and the benefit of surgery.
Footnotes
Consent
The patient gave his consent for the writing of this case report.
Declaration of conflicting interests
The authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
Funding
The authors received no financial support for the research, authorship, and/or publication of this article.