Glossopharyngeal neuralgia, also known as vagal glossopharyngeal neuralgia, refers to episodes of severe pain confined to one side of the glossopharyngeal nerve or the distribution area of the Eustachian branch of the vagus nerve – the posterior tongue and throat, which may radiate to the oropharynx or external ear.
1.Primary glossopharyngeal neuralgia. The etiology of primary glossopharyngeal neuralgia is still unclear, but microvascular compression of the glossopharyngeal nerve may be the main cause. The compression of the linguopharynx and vagus nerve by the posterior inferior cerebellar artery and other blood vessels causes demyelination of the linguopharynx and vagus nerve, resulting in a “short circuit” between the afferent impulses of the linguopharyngeal nerve and the vagus nerve, causing pain. The onset of the disease is over 40 years of age and is more common in men than women.
The clinical features of the disease are:
(1) The clinical manifestations and pain sites are different from those of primary trigeminal neuralgia, with pain occurring at the root of the tongue, pharynx, tonsils, deep ear and the posterior part of the jaw. Sometimes the pain in the deep part of the ear is the main manifestation.
(2) The attack and the nature of pain are the same as trigeminal neuralgia, the pain often comes on suddenly and stops suddenly, the duration of each attack is a few seconds or tens of seconds, usually not more than 2 minutes. The pain can also be severe like cutting, stabbing, tearing, burning, or electric shock.
(3) Triggering factors often trigger pain when swallowing, chewing, talking, coughing, or yawning.
(4) Trigger points. Trigger points are often present, mostly at the posterior pharyngeal wall, tonsils, tongue root, etc., and rarely in the external auditory canal.
(5) Other symptoms because swallowing movements often trigger painful episodes, although there is no pain between episodes, but the fear of triggering pain and afraid to eat, patients often show wasting, dehydration. Patients often show weight loss, dehydration, laryngeal spasm, cardiac rhythm disturbance and hypotensive syncope, etc.
(6) There are no positive signs in the neurological examination.
2. Secondary lingual-pharyngeal neuralgia. Some pontocerebellar horn tumors, arachnoiditis, vascular diseases, pharyngeal tumors or hypertelorism can provoke pain in the distribution area of the glossopharyngeal nerve, which is called secondary glossopharyngeal neuralgia.
Its clinical manifestations:
(1) Pain in the distribution area of the linguopharyngeal nerve: the pain attacks are long or persistent, and the triggering factors and trigger points may not be obvious, but are more severe at night.
The symptoms of linguopharyngeal nerve damage include: palatal arch paralysis, loss of sensation in the soft palate and pharynx, loss of taste and general sensation in the posterior 1/3 of the tongue, loss of gag reflex, and disturbance of parotid gland secretion.
(3) Damage to adjacent cerebral nerves: jugular foramen syndrome, posterior pharyngeal syndrome and Horner’s syndrome may occur.
(4) In case of nasopharyngeal cancer, a mass in the nasopharynx and enlarged lymph nodes in the neck may be found.
Clinical symptoms
1. more common in males than females, with onset of disease mostly after the age of 35
2. The pain is limited to the area innervated by the glossopharyngeal nerve and the auricular and pharyngeal branches of the vagus nerve, i.e., the posterior pharyngeal wall, tonsillar fossa, tongue root and deep external auditory canal, etc. It may radiate to the external ear, mandible and gingiva. The pain is usually unilateral, and only 2% of cases are bilateral. The pain is like a cut, pinprick, or electric shock, sudden, intense, lasting from a few seconds to a minute, and ranging from several to dozens of episodes per day.
3, . Pain with distinct episodes and periods of quiescence in most cases, sometimes as long as 1 year or more, but not self-resolving.
4. there may be painful “trigger points” at the base of the tongue, tonsillar fossa, and throat, often triggered by eating, swallowing, and speaking.
5. There is no abnormality on physical examination or cranial CT or MRI.
Clinical classification
There are two different clinical classifications of glossopharyngeal neuralgia. In the first method, there are three types of glossopharyngeal neuralgia: typical glossopharyngeal neuralgia, atypical glossopharyngeal neuralgia, and secondary glossopharyngeal neuralgia. Typical glossopharyngeal neuralgia is usually caused by severe pain in the oropharynx and ears due to vascular compression of the 9th and 10th cranial nerve roots that enter the lateral medulla oblongata. Atypical glossopharyngeal neuralgia is not limited to these areas, but can radiate to the forehead, external auditory canal, and auricle. Secondary glossopharyngeal neuralgia is caused by a tumor in the neck or skull base that damages the glossopharyngeal nerve. Glossopharyngeal neuralgia has also been associated with multiple sclerosis, but the onset is rare.
In contrast, Olese et al. classified two types of glossopharyngeal neuralgia: classic and symptomatic.
The diagnostic criteria for classic glossopharyngeal neuralgia are as follows:
1. sudden onset of facial pain lasting from a few seconds to no more than 2 min
2. At least 4 of the following conditions are met: pain unilaterally distributed in the posterior part of the tongue, tonsillar fossa, laryngopharynx, lower part of the inferior collar angle, or in the ear; sudden, sharp, pins-and-needles or burning pain; severe pain; chewing, swallowing, coughing, talking, or yawning can trigger the pain.
3. No neurological abnormalities.
4. Exclude other causes of pain by medical history, physical examination and special examination.
5. The duration of pain episodes is basically the same.
Symptomatic GPN meets the first two diagnostic criteria above, but also has the following conditions: the pain may persist between episodes; hyperalgesia in the area of the distribution of the glossopharyngeal nerve. In addition, the diagnosis requires a special examination or intraoperative clarification of the cause of the injury.
Site typing
The site of glossopharyngeal neuralgia is generally divided into two types.
①The area starts from the pharyngeal wall, tonsillar fossa, soft palate and the posterior 1/3 of the tongue, and then radiates to the ear; this type is the most common;
The painful area starts in the outer ear, deep part of the ear canal and the parotid area, or between the angle of the mandible and the mastoid, and rarely radiates to the pharyngeal side, which is rare. Occasionally, the pain is limited to the deep part of the outer ear canal, which only affects the tympanic branch of the linguopharyngeal nerve. The episodes are brief, usually lasting from a few seconds to a few minutes, ranging from a few times to dozens of times a day, especially when anxious and nervous, the general tendency is to have more and more frequent episodes and longer and longer durations, often with intervals of varying duration, during which the patient is as normal, sometimes with a large amount of saliva secretion or continuous coughing in the fashion of pain episodes, when the patient The patient may have a red face, sweating, tinnitus, deafness, lacrimation, elevated blood pressure, laryngeal spasm, vertigo, occasional cardiac arrhythmia such as tachycardia, bradycardia, or even transient arrest, hypotensive syncope, seizures, etc. There may be “trigger points” in the external ear, tongue, posterior pharynx and tonsillar fossa, which can develop when stimulated. The pain can also be radiated to the neck or shoulders, but it is extremely rare to have bilateral linguopharyngeal neuralgia.
Neurological examination
There are often no abnormal findings, which is a characteristic of this disease.
1. Episodes of severe pain lasting from a few seconds to a few minutes.
2. The pain involves the tonsils, the posterior pharyngeal wall, the back of the tongue, the larynx, the middle ear, and may radiate to the neck.
3. There may be painful trigger points at the root of the tongue, tonsil fossa, and throat, so it often affects swallowing, conversation, and chewing without other objective neurological signs. Patients with chronic prolonged disease may have a deviation of the uvula.
4. Painful episodes are occasionally accompanied by cardiac arrest, syncope, and convulsions.
5. Spraying 1% bupivacaine on the posterior pharyngeal wall or tonsillar area can reduce the attack to differentiate it from trigeminal mandibular branch pain.
6. Tympanic neuralgia, or otolaryngopharyngeal neuralgia, is caused by the involvement of the tympanic nerve of the linguopharyngeal nerve. The pain is paroxysmal and transient, limited to the deep part of one side of the ear and the posterior part of the ear, and radiates to the mandibular angle of the pharynx and the neck in severe cases. The pain may be spontaneous or induced by touching the ear canal, but there is no trigger point in the linguopharynx, so swallowing is not triggered.
Diagnosis: The diagnosis is usually clear based on the clinical features of the disease, and CT and MRI examinations help to exclude secondary lesions.
Differential diagnosis
1. trigeminal neuralgia: the third branch is easily confused with glossopharyngeal neuralgia. Spraying the posterior pharyngeal wall or tonsillar area with 4% cocaine or 1% pontocaine can be differentiated from trigeminal mandibular branch pain if the pain is reduced.
2. Supraglottic neuralgia: The supraglottic nerve is a branch of the vagus nerve, and the neuralgia can exist alone or be accompanied by linguopharyngeal neuralgia. If local anesthesia is performed in this area, the pain is often temporarily relieved, which can be distinguished.
3. Intermediate neuralgia: It is a severe pain in one side of the ear, with a long attack time, often accompanied by herpes in the external auditory canal or auricle, and sometimes can cause peripheral facial paralysis. Individuals with atypical presentation of otalgia only are not easily distinguished from glossopharyngeal neuralgia which is manifested as simple otalgia, and in this case, in addition to removal of the glossopharyngeal nerve, the intermediate nerve also needs to be removed during surgery.
4.Secondary linguopharyngeal neuralgia: the pain is persistent, with paroxysmal aggravation and no trigger point, and some linguopharyngeal nerve dysfunction (such as hypoesthesia of linguopharyngeal sensation and posterior tongue taste, dull pharyngeal reflex, soft jaw motor weakness, etc.) or other positive neurological signs can be seen on the affected side. Localized lesions may be found on cranial CT or MRI.
Treatment
The initial treatment of glossopharyngeal neuralgia is medication. In case of ineffective medication or with serious complications, surgical treatment should be actively used.
1. Drugs: Any drug used to treat primary trigeminal neuralgia can also be applied to glossopharyngeal neuralgia. Commonly used drugs include carbamazepine, phenytoinamide, heptaerythrone and baclofen, etc.
2.Chinese medicine: Chinese medicine, acupuncture, etc.
3.Nerve block: the method is radiofrequency treatment by percutaneous puncture of the jugular foramen, which is suitable for.
(1) Those who are ineffective in drug treatment or cannot tolerate the adverse effects of drugs.
(2) those who are elderly or in poor general condition and cannot tolerate craniotomy
(3) cases of combined multiple sclerosis. The main problems of this treatment method are high recurrence rate of pain (23%-54%) and difficulty in swallowing, choking and hoarseness caused by nerve damage.
4.Surgery: Since Laha and Jannetta considered vascular compression as the cause of pain in 1977, more scholars have found that the vertebral artery or posterior inferior cerebellar artery rides across the linguopharynx and vagus nerve root into the brainstem segment. At present, microvascular decompression has become the surgical method of choice for glossopharyngeal neuralgia. The cure rate can reach 99%.
Indications for surgery
(1) Those who have failed drug treatment such as carbamazepine or percutaneous puncture treatment.
(2) The pain can be relieved by applying 5% bupivacaine solution to the painful part of the pharynx or the point of the plate machine, which proves that it is indeed this disease.
(3) Patients in good general condition, without serious organic lesions, who can tolerate surgery.
(4) Excluding multiple sclerosis or tumor of the pontocerebellar horn and other lesions.
Contraindications
(1) Tumor found at the time of surgery and can be removed.
(2) The patient is too weak to tolerate the surgery.
Classic case procedure
After 8 years of left-sided glossopharyngeal neuralgia, the patient was completely cured by MVD without any symptoms.
The vascular loop compressing the nerve was revealed. Mostly at the linguopharyngeal and vagus nerves exiting the brainstem, the vertebral artery or posterior inferior cerebellar artery was seen to compress the nerve. The artery compressing the nerve is carefully freed under the microscope and Teflon cotton is filled between the nerve and the vessel. The thickened arachnoid and cerebellum with adhesions to the glossopharyngeal nerve should also be released. The patient is then asked to try to swallow saliva or drink a little liquid, and if the pain disappears, the operation is successful.