Glossopharyngeal neuralgia is an episodic severe pain confined to the posterior tongue and throat of the Eustachian branch of the glossopharyngeal nerve or vagus nerve that can radiate to the external ear.
Etiology and pathogenesis
The cause is unknown, but microvascular compression of the glossopharyngeal nerve is probably the main cause. Compression of the linguopharyngeal and vagus nerves by vessels such as the posterior inferior cerebellar artery causes demyelination of the linguopharyngeal and vagus nerves, resulting in a “short circuit” between the afferent impulses of the linguopharyngeal nerve and the vagus nerve, causing pain. Pontocerebellar tumors, aneurysms, skull base arachnoiditis, overgrown mastoids, ossification of the mastoid hyoid ligament, and head and neck trauma are the causes of secondary lesions.
Morbidity
The incidence of glossopharyngeal neuralgia is much lower than that of trigeminal neuralgia, with the ratio of the two being about 1:70-1:100, and patients are mostly located in the 50-year-old age group.
Clinical symptoms
1. more common in males than females, with the age of onset mostly after 35 years.
2. The pain is confined 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, with episodes ranging from several to dozens of times a day.
3. the pain has distinct episodes and resting periods in most cases, sometimes for up to 1 year or more, but does not heal spontaneously.
4. there can be painful “trigger points” at the root of the tongue, tonsil fossa, and throat, often triggered by eating, swallowing, and speaking.
5, about 10% of cases can develop into vagal glossopharyngeal syncope, i.e., episodes of bradycardia, cardiac rhythm disturbances, hypotension, syncope, convulsions and even cardiac arrest.
6. About 10% of the cases of glossopharyngeal neuralgia combined with trigeminal neuralgia. Spraying the posterior pharyngeal wall or tonsillar area with 4% cocaine or 1% pontocaine, if the pain disappears, it can be distinguished from trigeminal mandibular branch pain.
7. Physical examination and cranial CT or MRI examination are not abnormal.
Diagnosis
The diagnosis is usually clear based on the clinical features of the disease, and CT and MRI examinations help to exclude secondary lesions. 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 relieved, and is a diagnostic test.
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, if the pain is reduced it can be differentiated from trigeminal mandibular branch pain.
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 first choice of treatment for linguopharyngeal 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 drug reactions.
(2) those who are elderly or in poor general condition and cannot tolerate craniotomy
(3) in 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 due to nerve damage.
4.Surgery: Microvascular decompression is the safest and most effective surgical treatment method at present, other surgical methods are used less frequently due to poor treatment effect and many surgical complications. Surgical treatment is suitable for.
(1) Those who have failed in drug or percutaneous puncture treatment.
(2) Patients in good general condition, without serious organic lesions, who can tolerate surgery.
(3) Those who exclude lesions such as multiple sclerosis or pontocerebellar horn tumors. Most patients’ pain disappears after surgery, and 98% of patients can be cured.