An unusual presentation of unilateral vagoglossopharyngeal neuralgia accompanied by unilateral accessory nerve palsy

Abstract

Background

Vago-glossopharyngeal neuralgia (VGN) is a rare condition characterized by neuropathic pain in the areas innervated by the glossopharyngeal and vagus nerve. Diagnosis can be challenging due to its rarity and the need to differentiate it from other sources of pain. Neurovascular conflicts involving the glossopharyngeal nerve and surrounding vasculature are often implicated in the development of VGN. Surgical interventions, such as microvascular decompression, have shown promise in relieving symptoms, but long-term outcomes remain poorly understood. This case report presents a unique manifestation of VGN accompanied by unilateral accessory nerve palsy and syncope, shedding light on the complexities involved in diagnosis and management.

Case presentation

The presented case involves a 42-year-old patient without comorbidities with a 1-year history of syncope, dysphonia, cough, oropharyngeal pain, dysphagia, right periaricular pain, and weakness of the right sternocleidomastoid and trapezius muscle. After an initial evaluation, compression of the right cranial nerves IX, X, and XI by the posterior inferior cerebellar artery (PICA) was identified as the cause. The patient underwent microvascular decompression, which provided 3 years of symptom relief. However, symptoms recurred with additional manifestations, including left periauricular pain and increased syncopal episodes of cardiogenic origin. A follow-up brain MRI revealed compression of the left cranial nerves IX and X. A second surgical intervention targeting the left side resulted in partial improvement but symptom reappearance after 1 year. Finally, a third surgery involving the left side was performed, and along with isolating the affected cranial nerves, two superior rootlets of the vagus nerve were rhizotomized. Postoperative recovery was successful, with complete resolution of symptoms and no recurring issues during follow-up examinations.

Conclusion

This case underscores the complexity of diagnosing and managing neurovascular conflicts associated with VGN pain syndrome. While initial microvascular decompression provided relief, the recurrence of symptoms and emergence of new manifestations highlight the challenges in managing this condition. Precise identification of nerve compression and targeted surgical interventions, such as sectioning the superior roots of the vagus nerve, offer potential efficacy in refractory cases. Further studies and long-term follow-up are necessary to gain comprehensive insights into the progression and outcomes of these interventions.

Background

VGN accompanied by unilateral accessory nerve palsy is a pathological condition that has not been previously documented in the literature, and as a result, its incidence remains unknown. VGN occurring in isolation represents only 1% of all cases of neuralgia and is characterized by symptoms such as dysphagia, pain in the areas surrounding the pinna, base of the tongue, and tonsillar fossa. In rare cases, syncopal symptoms may also be present [1, 2]. The estimated incidence of VGN ranges from 0.2 to 0.7 cases per 100,000 inhabitants per year, posing a challenge for diagnosis as it is often confused with other conditions such as trigeminal neuralgia or superior laryngeal nerve neuralgia [3].

One of the main causes of VGN is neurovascular conflict, which occurs when a vascular structure abnormally interacts or compresses a nervous structure within the nervous system. This can happen when a blood vessel, such as an artery, compresses or exerts pressure on a neighboring nerve root, resulting in various neurological symptoms and disorders. Additionally, VGN can be caused by traumatic, infectious, or idiopathic factors, albeit less frequently [4].

Accessory nerve palsy, characterized by the paralysis of the sternocleidomastoid or trapezius muscles and potential torticollis, can also be considered as a differential diagnosis [4, 5]. The causes of accessory nerve palsy are like those of VGN; however, the association between VGN and accessory nerve palsy is not well-documented.

Following the exclusion of other pathologies, imaging studies such as magnetic resonance imaging (MRI) and computed tomography (CT) are valuable in identifying the neurovascular conflict associated with these conditions [5].

The purpose of this case report is to describe a unique occurrence of neuralgia affecting the glossopharyngeal and vagus nerves, accompanied by accessory nerve palsy. The patient exhibited uncommon symptoms, including challenging-to-diagnose syncopal episodes. Furthermore, this report highlights the potential limitations of microvascular decompression of the glossopharyngeal nerve as a treatment for this condition.

Case presentation

The presented case involves 42-year-old with no underlying comorbidities who presented at our institution with a 1-year history of syncope, dysphonia, cough, oropharyngeal pain, dysphagia, right periaricular pain, and weakness of the right sternocleidomastoid and trapezius muscle. The syncope episodes occurred irrespective of the patient's position (supine or decubitus) and were not associated with physical exertion or rest. A tilt table test was conducted to investigate the syncope, yielding negative results. Given the patient's age and the absence of cardiac rhythm abnormalities on the electrocardiogram, a Holter monitor was employed, revealing episodes of transient sinus bradycardia. Consequently, the syncope was attributed to reduced cerebral blood flow resulting from bradycardia of undetermined etiology.

Regarding the dysphagic symptoms, which initially manifested as difficulty in swallowing liquids and later progressed to include solids, the patient underwent evaluation by an otorhinolaryngologist to investigate potential pharyngeal or laryngeal causes of the pain. After excluding any otorhinolaryngological causes, contrast-enhanced magnetic resonance imaging (MRI) was performed, revealing compression of the right cranial nerves IX, X, and XI by the PICA.

Once the neurovascular conflict was identified, the patient was prescribed anticonvulsant medication as a conservative management approach for a minimum duration of 4 weeks. However, the symptoms did not improve. Consequently, microvascular decompression was considered as a potential treatment option.

During surgical intervention, it was observed that the right PICA was directly compressing the IX, X, and XI cranial nerves (Fig. 1). Meticulous isolation of the lower cranial nerves was performed using a sponge-type material, and the procedure was completed without any complications. After the surgery, the patient remained asymptomatic for 3 years.

Fig. 1

Right vagoglossopharyngeal neurovascular conflict

However, the patient subsequently sought medical evaluation due to the recurrence of similar symptoms, including dysphonia, cough, oropharyngeal pain, and dysphagia. Notably, the patient now also experienced left periauricular pain and a significant increase in syncopal episodes, which were determined to have a cardiogenic origin based on the presence of sinus bradycardia observed in the electrocardiogram. Considering the patient’s history of neurovascular conflict, a follow-up brain MRI was conducted, revealing compression of the IX and X cranial nerves on the left side of the brain (Fig. 2).

Fig. 2

Magnetic resonance brain imaging in axial T2 section showing left-sided neurovascular conflict

Consequently, a second surgical intervention was performed, this time focusing on the contralateral side. Clear points of contact with the left vertebral artery were identified, and the IX and X cranial nerves were carefully isolated using a sponge-type material. Although there was partial improvement of the symptoms following the surgery, they reappeared with maximum intensity 1 year later.

The patient’s final visit occurred 2 years after the previous surgery, and the condition was deemed refractory to surgical intervention due to the persistence of symptoms including hoarseness, cough, oropharyngeal pain, and dysphagia. After ruling out any otolaryngological causes, a new MRI scan was performed, revealing evident compression of the left cranial nerves IX, X, and XI. Subsequently, the patient underwent another surgical procedure focused on the left side. During the surgery, compression of the IX, X, and XI cranial nerves by the left vertebral artery was observed (Fig. 3). The affected cranial nerves were carefully isolated from the vertebral artery employing Surgi-PVA ophthalmic sponges, and in addition, two superior rootlets of the vagus nerve were rhizotomized without encountering any complications (Fig. 4).

Fig. 3

Vagoglossopharyngeal neurovascular conflict and left accessory nerve

Fig. 4

Microvascular decompression of the left glossopharyngeal, vagus and accessory nerves

After the surgical procedure, the patient experienced a favorable postoperative recovery, with complete resolution of all symptoms, including syncopal episodes. A follow-up examination conducted 3 months post-surgery confirmed the absence of any recurring symptoms. As a result, the patient has not required further consultations regarding the same set of symptoms.

Discussion

VGN is a rare and challenging-to-diagnose condition characterized by neuropathic pain in the regions innervated by the glossopharyngeal and vagus nerves, including the larynx, pharynx, and inner ear. It presents a difficulty in distinguishing between pain originating from the ninth cranial nerve and the tenth pair [1]. Accessory nerve palsy, on the other hand, involves weakness or spasms of the sternocleidomastoid or trapezius muscles. Pain in VGN typically occurs after activities such as chewing, coughing, yawning, or speaking, with durations ranging from a few seconds to minutes. Atypical symptoms may include cardiac arrhythmias and syncopal episodes [6].

VGN and accessory nerve palsy can be either primary, without a known anatomical cause, or secondary to factors such as masses in the cerebellopontine angle, oropharyngeal tumors, ossification of the stylohyoid ligament, multiple sclerosis, or vascular malformations. The primary cause usually involves a conflict between the ninth and tenth cranial nerves and the PICA and/or the vertebral artery [7].

The best way to characterize the neurovascular conflict is through a brain MRI or CT scan [8]. MRI is considered the ideal test since it allows localization and characterization of the lesion, as well as assessment and surgical planning for the best treatment of patients [9].

For the management of VGN and accessory nerve palsy, anticonvulsant drugs like carbamazepine, oxcarbazepine, gabapentin, or pregabalin are considered the first line of treatment [10]. In cases resistant to medical management, microvascular decompression through craniotomy is preferred, although percutaneous procedures such as radiofrequency and rhizotomy, as well as Gamma Knife radiosurgery, have also been described [5].

When opting for microvascular decompression, it is essential to address the challenge of distinguishing between the ninth and tenth cranial nerves as the origin of symptoms. Some authors recommend partial removal of the glossopharyngeal nerve and upper rootlets of the vagus nerve (approximately 1–3) to achieve better therapeutic outcomes. However, this segment of the vagus nerve also provides fibers to the superior and recurrent laryngeal nerves, which can lead to complications like dysarthria or dysphagia, making intervention in these segments risky [11].

Recent studies by Krüger et al. have suggested that rhizotomy of the upper rootlets of the vagus nerve yields higher rates of symptom relief. They classified two types of rootlets: Type A (sensory) and Type B (motor) and used intraoperative neurophysiological monitoring to reduce the chances of motor complications such as dysphagia or dysphonia. The study concluded that when the upper rootlets were predominantly sensory fibers, patients who underwent rhizotomy experienced better symptom relief with no associated complications. In cases where the rootlets were predominantly Type B, intervention in the vagus nerve was not recommended, with a complication rate of approximately 19%. The anatomical and physiological basis for this lies in the close relationship between the vagus and glossopharyngeal nerves in their origin in the solitary tract and their trajectory, although this relationship is not yet fully understood [12].

Currently, there are no reported cases in the literature of unilateral VGN combined with unilateral accessory nerve palsy and syncope. However, authors such as Ganaha et al. [13] describe a case of a patient in her early twenties who had previously undergone microvascular decompression of the right glossopharyngeal nerve. She presented with intractable left hemifacial pain initially associated with speech, chewing, or mouth opening. Initial treatment with pharmacotherapy and steroid infiltration did not provide sufficient relief. Magnetic resonance imaging and cranial tomography did not reveal any abnormalities. Subsequently, the patient underwent a left suboccipital surgery where the left glossopharyngeal nerve and the upper rootlets of the vagus nerve were sectioned, with intraoperative monitoring of nerves VII, VIII, X, and XI. This procedure had previously been successfully performed on the right side. In the postoperative period, the patient experienced a prompt recovery and complete resolution of symptoms. The authors suggest that the sectioning of the ninth and upper tenth roots can be safe if preoperative functional tests indicate a minimal risk of postoperative oropharyngeal and cardiac complications.

In our present case, due to the refractory nature of the symptoms to medical and surgical management, we decided to intervene on two upper rootlets of the vagus nerve during the most recent surgical procedure. We believe that sectioning the upper rootlets of the vagus nerve may be a suitable option in complex cases where symptomatology does not improve despite surgical management. This decision involves carefully weighing the risk–benefit ratio and the potential for injury to the recurrent or superior laryngeal nerve. Additionally, in patients with vasovagal syncope of unknown cause, resistant to fluid therapy and medications, it is advisable to consider a possible neurovascular conflict involving the ninth and tenth cranial nerves as a potential underlying cause of the symptoms.

It is important to note that this study is based on a single case, and further research involving a larger number of patients is needed to establish a correlation between VGN neuralgia and syncope. Moreover, the efficacy and outcomes of rhizotomy of the superior rootlets of the vagus nerve remain a topic of debate, and future studies are required to provide more insights into the postoperative effects of this technique.

Conclusion

This case highlights a unique presentation of unilateral VGN along with unilateral accessory nerve palsy and syncope. The rarity of this condition and the difficulty in differentiating the referred pain from other areas, particularly the larynx, present significant challenges in diagnosis and treatment. Surgical intervention, specifically the sectioning of the superior rootlets of the vagus nerve, emerges as a potentially effective approach in relieving the persistent symptoms associated with VGN.