What is glossopharyngeal neuralgia?

Glossopharyngeal Neuralgia

Glossopharyngeal neuralgia is a rare cranial neuropathic pain syndrome characterized by severe, paroxysmal, stabbing pain in the oropharyngeal and otic regions that is classically triggered by swallowing, and is typically caused by neurovascular compression of the glossopharyngeal nerve. The first-line treatment for glossopharyngeal neuralgia is carbamazepine, with gabapentin being a suitable alternative when carbamazepine is not tolerated or contraindicated. 1, 2

Clinical Presentation

• Pain characteristics:

  • Severe, paroxysmal, electrical shock-like pain
  • Located in the oropharyngeal region, posterior tongue, tonsil area, ear canal, or beneath the angle of the jaw
  • Episodes last from seconds to minutes
  • Typically unilateral (bilateral cases are extremely rare) 3

• Triggers:

  • Swallowing (most common)
  • Talking
  • Yawning
  • Coughing
  • Stimulation of the pharynx or deep throat 4, 5

• Associated symptoms:

  • May include tonsillar pain
  • Impaired taste and sensation along the posterior one-third of the tongue and palate
  • In rare cases, cardiac arrhythmias and syncope during pain episodes 3

Pathophysiology

Glossopharyngeal neuralgia is typically caused by:

1. Neurovascular compression (most common): Compression of the glossopharyngeal nerve (CN IX) by blood vessels, particularly the posterior inferior cerebellar artery (PICA) 6

2. Secondary causes:

   • Trauma
   • Elongated calcified stylohyoid ligament
   • Neoplasms along the course of the nerve
   • Skull base lesions affecting the jugular foramen 4

Diagnostic Approach

1. Clinical diagnosis: Based on characteristic pain pattern and triggers

2. Imaging studies:

   • MRI orbits, face, and neck with contrast: First-line imaging to evaluate the entire course of CN IX, including intracranial and extracranial portions 4
   • MRA focused on posterior skull base: To assess for neurovascular compression 4
   • CT neck with contrast: Complementary to MRI to evaluate:
     • Skull base erosion
     • Deep space neck masses
     • Bony margins of jugular foramen
     • Extracranial course of CN IX 4

3. Differential diagnosis:

   • Trigeminal neuralgia (most commonly confused with GPN) 7
   • Burning mouth syndrome
   • Post-herpetic neuralgia
   • Atypical odontalgia
   • Oropharyngeal malignancy 8

Treatment Algorithm

1. First-Line Medical Therapy

• Carbamazepine: Start with low dose and titrate gradually 1, 2
  • FDA-approved for glossopharyngeal neuralgia
  • Monitor for side effects: skin rash, blood dyscrasias, liver dysfunction

2. Alternative Medical Therapies (if carbamazepine fails or is contraindicated)

• Gabapentin: Starting at 300 mg daily with gradual titration 8, 2
• Eslicarbazepine acetate 2
• Other anticonvulsants: Pregabalin, lamotrigine

3. Minimally Invasive Procedures (for medication-refractory cases)

• Nerve blocks
• Pulsed radiofrequency ablation
• Percutaneous radiofrequency thermocoagulation 2
• Stereotactic radiosurgery (SRS): Consider for patients with poor surgical candidates
  • Requires doses of 75 Gy or higher
  • Note: Long-term pain relief rates are lower than with surgical options 6

4. Surgical Management (for medication-refractory cases)

• Microvascular decompression (MVD): First-line surgical option

  • Success rate: 85% immediate pain relief; 65-90% long-term pain relief
  • Complications: Transient hoarseness, dysphagia 6

• Rhizotomy: Consider when no vascular compression is identified

  • Success rate: 85-100% immediate pain relief
  • Higher risk of complications: Dysphagia, dysesthesia 5, 6

Special Considerations

• Monitoring: Regular follow-up to assess treatment efficacy and side effects

• Medication warnings:

  • Do not stop carbamazepine suddenly (may precipitate seizures)
  • Asian patients may require genetic testing before starting carbamazepine due to higher risk of serious skin reactions 1

• Surgical decision-making:

  • MVD alone is preferred over MVD with rhizotomy when possible, as it has fewer adverse effects 6
  • Consider patient's general condition when selecting between surgical options

• Rare complications:

  • Cardiac arrhythmias and syncope may occur during pain episodes in some patients
  • Bilateral GPN is extremely rare but may require staged surgical intervention 3