Glossopharyngeal neuralgia manifests with a pain that is sharp and stabbing in nature. It is generally localized in the throat but can also radiate to the ear or the other way around. The localization of the pain is critical in establishing the diagnosis. Structures and organs involved include the base of the posterior part of the tongue, the tonsils, the pharynx, the mandibular angle, the inner ear and the eustachian tube [8].

Pain in glossopharyngeal neuralgia occurs in episodes but with a gradual and subtle onset that can last for 30 seconds. There is a continuous presence of an ache in the region of the pain, even in the absence of a pain crisis. The pain more typically occurs during the days and can last for months at times. It is associated with particular triggers such as swallowing cold fluids, talking, chewing, sneezing, contact with the gums or the oral mucosa, cleaning of the throat, jerky movements of the head, moving the jaw in the lateral direction or raising the hand on the side of the pain. The pain can sometimes be further triggered by establishing contact with the skin around the ear on the affected side as well as by touching the external auditory canal [9].

Glossopharyngeal neuralgia may also be associated with a number of other symptoms such as vomiting, a sensation of edema in the face, tinnitus, vertigo and involuntary movements. It may be difficult to distinguish from intermedius neuralgia especially when they present similarly with decreased hearing. Furthermore, giant cell arthritis can also present with a pain with similar characteristics.

Vagoglossopharyngeal neuralgia is a subtype of the condition that is associated with vagal symptoms such as convulsions, asystole and syncope. This is caused by the intricate anatomical relationship between the glossopharyngeal nerve, the intermedius and the vagus and may complicate evaluation by neurologists and neurosurgeons [10].

In comparison to trigeminal neuralgia, the exact location of pain is only later clearly identified by the patient, making diagnosis difficult from the first clinical encounter.

The diagnosis of glossopharyngeal neuralgia is established by examining the full clinical picture, in addition to performing imaging and laboratory tests. Patients typically experience a stabbing pain that presents in a unilateral fashion in the throat. They can also complain of pain in the tongue and in the ear. Other characteristic symptoms include intense pain that is triggered by contact with the tonsils or the soft palate. Patients with a highly suggestive presentation may undergo further testing.

A swab test is performed by making contact with the back of the throat, followed by an application of anesthetic. This, in turn, is followed by further contact, in the attempt to re-establish a painful reaction. A finding consistent with glossopharyngeal neuralgia is the absence of pain after the administration of an anesthetic.

Imaging modalities can also be useful in establishing the diagnosis. Computed tomography (CT) and magnetic resonance imaging (MRI) will help visualize any compression of the ninth cranial nerve due to cancerous growths or particular tumors [11]. Eagle syndrome is suggested when imaging reveals a long styloid process that is impinging on the nerve.

Workup of glossopharyngeal neuralgia proceeds similarly to that of trigeminal neuralgia. Diagnosis is contingent on establishing the exact location of the pain in the face. Unilateral pain in the throat and the ears is suggestive of the diagnosis.

Pharmacotherapy is usually the initial treatment of choice in the majority of cases. Anticonvulsants play a prominent role and medications that generally show benefit include gabapentin, oxcarbazepine and carbamazepine [12]. Painkillers bought without a medical prescription are generally ineffective. Antidepressants can sometimes be employed in conjunction with anticonvulsants or on their own. Common side effects involved with the most used drugs are fatigue, confusion, nausea, rash and a general irritation of the skin. In case a particular drug causes bothering side effects, the dose can be lowered or it can be substituted with another drug. Lidocaine is sometimes useful when a quick effect is needed; for example, in cases where pain is preventing the patient from swallowing. Response to treatment can be monitored with blood tests and can also be used to adjust the dose of drugs as well as the kind and combination of medication that is being used.

Failure to respond to treatment, especially when the nerve structure is compressed, can prompt the physician to opt for surgery. The surgical procedure of choice is called microvascular decompression. It aims to decrease the pressure on the nerve by changing the direction of the blood vessels [13]. General anesthesia is necessary to perform the procedure and may require the patient to spend at least one night in the hospital.

Microvascular decompression is performed by first undergoing a craniotomy, in which an incision behind the ears is made in the skull. This allows the visualization of the ninth cranial nerve and permits the surgeon to access the area where the nerve connects to the brainstem. He can then divert the course of the blood vessels and relieve the pressure over the nerves. Microvascular decompression has a high success rate (averaging 85%) and is usually followed by the placement of a sponge over the nerve for additional protection. Potential complications may take place although the benefit outweighs the risks. Some side effects of the operation include infection, bleeding, facial muscle weakness, visual problems and numbness.

On the other hand, Eagle syndrome is treated by reshaping the styloid process through minimally invasive methods. Patients who do not respond to the abovementioned procedure may ultimately require high stimulation of the cervical spinal cord.

Prognosis varies from case to case. Some patients may experience only one attack of glossopharyngeal neuralgia, while others may suffer from recurrent episodes over months and years. These generally occur in clusters, separated by remission periods that can either be long or short. Morbidity associated with the condition includes weight loss due to a fear of drinking, eating and chewing given the association of these activities with the disease.

The underlying causes of glossopharyngeal neuralgia are still uncertain, but it is thought that damage to the nerve occurs, either due to the ageing process or from other causes that lead to its deterioration. This, in turn, results in the failure of correct transmission of the somatic and autonomic nervous signal from the involved structures to the brain. Common causes that end up in leading to significant damage to the nerve include direct injury, infection in its vicinity, multiple sclerosis, malignancies of the oral cavity and compression by a blood vessel [4]. The latter represents the most common cause. Eagle syndrome is a very rare entity, characterized by a long styloid process that directly compresses the nerve.

Incidence of glossopharyngeal neuralgia is thought to vary between 0.2 and 0.7 in every 100,000 individuals every year [5]. Thus, it is a very rare condition and can account only for 0.2% to 1.3% of all causes of facial pain. Nonetheless, incidence may be underestimated due to poor awareness in the general population. Unlike trigeminal neuralgia, glossopharyngeal neuralgia is more common on the left side of the face with a ratio of 3:2. In addition, bilateral involvement is also more common in trigeminal neuralgia than glossopharyngeal neuralgia. Approximately 10% of all cases will suffer from seizures, and some patients may also experience autonomic dysfunction manifesting with bradycardia and a decrease in sympathetic muscle tone [6]. Very rarely, glossopharyngeal neuralgia can only manifest as syncope without any pain.

The ninth cranial nerve, also called the glossopharyngeal nerve, contains both sensory and motor fibers. Sensory input in the nerve is somatic in nature and originates from the posterior base of the tongue, the mastoid, the middle ear, the oropharynx and the eustachian tube. The tympanic part of the Jacobson's nerve carries sensory innervation to the mastoid and the inner ear. Additional non-somatic special sensory input is transmitted from the carotid body and sinus as well as the posterior third of the tongue. The latter carries taste fibers whereas the chemoreceptors are present in the carotid body and baroreceptors in the carotid sinus [7]. On the other hand, motor fibers innervate the stylopharyngeus muscle and parasympathetic fibers in the parotid gland.

The carotid sinus nerve may play an important part in the pathophysiology of the disease. This branch carries fibers from both the carotid sinus and body and is involved in respiratory function as well as in the circulatory reflex. Its involvement can account for the presence of arrhythmias in glossopharyngeal neuralgia.

There are no current preventive measures for glossopharyngeal neuralgia.

Glossopharyngeal neuralgia is a medical condition that describes damage to the glossopharyngeal nerve, the ninth cranial nerve, that can lead to excruciating pain in areas it innervates as well as occasional disturbances in its autonomic function [1]. Glossopharyngeal neuralgia is a very rare condition and, unlike trigeminal neuralgia, it tends to affect the left side more than the right [2]. Causes are multifactorial, but the most common involves direct pressure from nearby blood vessels. Other potential etiologies include infection, malignancy, multiple sclerosis and trauma. Patients present with a very sharp pain in the area of distribution of the nerve, in particular in the throat, with radiation to the ear [3]. The pain tends to occur in episodes separated by periods of remission. Some patients may only suffer one episode while others have recurring crises for years at a time. The pain is usually triggered by chewing, swallowing and touching the base of the tongue or the gums. Other associated symptoms include vertigo, tinnitus and, in some cases, seizures, loss of sympathetic tone and syncope. The latter are caused by the involvement of nerve fibers coursing in the carotid sinus and body. Diagnosis is established after assessing the full clinical picture, performing physical exam procedures and occasionally with imaging. Strong localization of the pain is critical in the establishment of the diagnosis. Imaging can also help in detecting any tumors or lesions that might be compressing the nerve. Treatment is primarily directed at controlling symptoms. Over the counter pain medications are generally ineffective and, instead, anticonvulsants are the preferred pharmacotherapeutic agents. Antidepressants may also be used alone or in combination with anticonvulsants. Surgery is reserved for resistant cases and consists of craniotomy, followed by a relief of the vascular pressure over the nerve.

Glossopharyngeal neuralgia is a medical condition that describes the irritation of a very important nerve that originates in the brain and supplies several structures in the face and the thorax. Irritation occurs generally due to compression from nearby vessels but can also be caused by infection, malignancy, multiple sclerosis or a long styloid process, a bone that is normally part of the cranium. Patients present with severe pain that is localized in the area of the distribution of the nerve. This region encompasses the posterior third of the tongue, the throat and the inner ear. The pain is shooting and sharp and tends to be triggered by chewing, swallowing or by touching the gums or the oral cavity. Some cases can also be associated with seizures, loss of muscle tone and syncope. This is because the nerve also carries fibers that are involved in maintaining posture, breathing and heart rhythm. Diagnosis is established clinically with history and physical exam, although in some cases imaging may reveal a lesion or a tumor compressing the nerve. It is critical to confirm the local nature of the pain. Most cases present with unilateral pain on the left side. Treatment is directed at controlling the associated pain. Over the counter medications are generally not effective. Drugs that are commonly used to treat epilepsy can improve the pain as well as certain antidepressants. Surgery is only reserved for resistant cases, and is performed by making an incision in the skull, accessing the nerve and diverting the compressing vessels.

1. Headache Classification Committee of the International Headache Society. The International Classification of Headache Disorders. 2nd ed. Cephalalgia. 2004; 24(suppl 1):9-160.
2. Bruyn GW. Glossopharyngeal neuralgia. Cephalalgia. 1983; 3:143–157.
3. Bohm E, Strang RR. Glossopharyngeal neuralgia. Brain. 1962; 85:371-88.
4. Weisenburg TH. Cerebellopontine tumour diagnosed for six years as tic douloureux: the symptoms of irritation of the ninth and twelfth cranial nerves. JAMA. 1910; 54:1600-4.
5. Katusic S, Williams DB, Beard CM, et al. Incidence and clinical features of glossopharyngeal neuralgia, Rochester, Minnesota, 1945–1984. Neuroepidemiology. 1991; 10:266–275.
6. Esaki T, Osada H, Nakao Y,, et al. Surgical management for glossopharyngeal neuralgia associated with cardiac syncope: two case reports. Br J Neurosurg. 2007; 21:599–602.
7. Patten JP. Basic Sciences . In Scott Brown's Otolaryngology. Fifth edition. Edited by Kerr AG, Stephens D. Butterworth Heinemann, Oxford. 1987; p. 379-407.
8. Evans RW, Torelli P, Manzoni GC. Expert opinion. Glossopharyngeal neuralgia. Headache. 2006; 46:1200-2.
9. Webb CJ, Makura ZG, McCormick MS. Glossopharyngeal neuralgia following foreign body impaction in the neck. J Laryngol Otol. 2000; 114:70-2.
10. Ozenci M, Karaoguz R, Conkbayir C, et al. Glossopharyngeal neuralgia with cardiac syncope treated by glossopharyngeal rhizotomy and microvascular decompression Europace. 2003; 5:149-52.
11. Fischbach F, Lehmann TN, Ricke J, et al. Vascular compression in glossopharyngeal neuralgia: Demonstration by high-resolutionMRI at 3 tesla. Neuroradiology. 2003; 45:810-11.
12. Dworkin RH, O'Connor AB, Backonja M, et al. Pharmacologic management of neuropathic pain: Evidence-based recommendations. Pain. 2007; 132:237-51.
13. Ferroli P, Fioravanti A, Schiariti M, et al. Microvascular decompression for glossopharyngeal neuralgia: A long-term retrospectic review of the Milan-Bologna experience in 31 consecutive cases. Acta Neurochir (Wien). 2009; 151:1245-50.