Glossopharyngeal Neuralgia

This information is designed only to help patients talk with their physicians about Glossopharyngeal Neuralgia (GPN) and is not intended to provide treatment guidelines.

Introduction

Glossopharyngeal neuralgia is a very rare neurologic condition that causes intermittent, extremely painful, one-sided throat pain. It is exactly analogous to the much more common trigeminal neuralgia (where the pain is in the face) but the affected nerve is the glossopharyngeal instead of the trigeminal. Each glossopharyngeal nerve  (there is one on the right and one of the left) is responsible for sensation in the back of the tongue and throat. That is why the pain is felt in the back of the tongue and throat. The pain is triggered by touching this area – i.e. by swallowing.

By 2015, we have seen well over a 1,000 patients with trigeminal neuralgia but only 14 with glossopharyngeal neuralgia. It is truly rare – a hundred times less common as trigeminal neuralgia.

The type of pain is identical to trigeminal neuralgia when it comes – “electrical bolts of lightning going down the back of my tongue” or “like swallowing shards of glass“. Only the location is different – throat not face. The pain is typically brief and lasts only a few seconds but the attacks can be multiple. Patients often mistakenly report that their pain is constant but it is really repeated bouts of intermittent pain. This is an important distinction. I have seen two patients with truly constant pain in the throat that turned out to be a neuropathic deafferentation pain not GPN.

Rarely (less than half the time) patients with glossopharyngeal neuralgia get symptoms related to the Vagus nerve. The vagus nerve (cranial nerve X) is located immediately beside the glossopharyngeal and can be compressed by the same blood vessel. When the vagus nerve is involved, patients can feel pain deep in their ear. Strong vagus nerve involvement can cause profound slowing of the heart rate – these patients get episodes where they feel their throat pain and then suddenly lose consciousness (faint) because their heart stops for a moment! This unusual condition is sometimes called glossopharyngeal-vagal neuralgia.

The cause of glossopharyngeal neuralgia is typically a long time compression of the nerve by an adjacent blood vessel. This blood vessel is typically the posterior inferior cerebellar artery or PICA. We believe the blood vessel wears away the insulation of the nerve and allows the nerve to ‘short-circuit’. Over the years, the condition will typically fluctuate with symptoms going away for several months (remission) and then returning again (relapse). The natural history of this condition is slow worsening – remissions get shorter and relapses get more severe over the years.

Medical Treatment

Just like trigeminal neuralgia, glossopharyngeal neuralgia can be treated with medications. The medications and rational are the same – anti-epileptic medications to stop the nerve from ‘short circuiting’. Patients can try a variety of medications under the supervision of their neurologist. There are many different medications that can be effective (e.g. carbamazepine (Tegretol), Neurontin (Gabapentin), pregabalin (Lyrica)).

In general, if the medications can control your symptoms, there is no need for surgery. If the medications can not control your pain OR if the side effects of the medications are intolerable (e.g. sedation) then you are a potential candidate for surgery.

 

Surgical Treatment

The benefits and risks of surgery must be discussed directly with your neurosurgeon. The risks can vary between centres with different experience.

Just like trigeminal neuralgia, a microvascular decompression of the glossopharyngeal nerve will work in the vast majority of cases. Unfortunately, there is often very little room around the nerve to push the vessel into. Because the nerve and vessel with Teflon remain in close proximity, recurrent compression with recurrent painful symptoms is a problem. Some surgeons (including our team) recommend cutting the glossopharyngeal nerve instead of decompressing it. This reduces the chance of recurrence and is well tolerated by the patient.

When the upper fibres of the Vagal nerve are involved the situation becomes more complex. Ideally, the surgery in those cases would also include cutting the upper sensory branches of the Vagal nerve. Cutting the motor branches of the vagal nerve will cause difficulty swallowing and a hoarse voice. In order to avoid the motor branches of the vagal nerve, we have published our recommended method of special intraoperative monitoring.