What is the treatment for trigeminal neuralgia?

Trigeminal Neuralgia: Diagnosis and Treatment

Trigeminal neuralgia should be treated initially with carbamazepine or oxcarbazepine as first-line medications, with surgical intervention recommended when medication fails to control pain or causes intolerable side effects. For optimal outcomes in terms of mortality, morbidity, and quality of life, patients with trigeminal neuralgia should be started on carbamazepine (200-1200 mg/day) or oxcarbazepine, and referred for neurosurgical evaluation if medical therapy is ineffective or poorly tolerated. 1, 2, 3

What is Trigeminal Neuralgia?

Trigeminal neuralgia is characterized by:

• Sudden, unilateral, severe, brief, stabbing, recurrent episodes of pain in the distribution of one or more branches of the trigeminal nerve 1
• Typically triggered by innocuous stimuli (e.g., chewing, speaking, brushing teeth, light touch) 4
• Pain-free intervals between attacks
• Profound negative impact on quality of life

Classification:

1. Primary Trigeminal Neuralgia:

   • Classical - associated with neurovascular compression of the trigeminal nerve
   • Idiopathic - no identifiable cause

2. Secondary Trigeminal Neuralgia:

   • Caused by underlying pathology (tumors, multiple sclerosis, etc.) 3

Diagnostic Approach

Diagnosis is primarily clinical, but imaging is essential to rule out secondary causes:

• MRI with high-resolution sequences is recommended for all patients with suspected trigeminal neuralgia 3

  • No clinical characteristics can reliably exclude secondary trigeminal neuralgia
  • If MRI is not possible, trigeminal reflexes can be used as an alternative

• Clinical features to identify:

  • Distribution of pain (which trigeminal branches are affected)
  • Character of pain (sudden, severe, stabbing)
  • Trigger factors
  • Response to previous treatments

Treatment Algorithm

1. First-Line Medical Therapy:

• Carbamazepine (200-1200 mg/day divided doses) 2

  • Start at low dose (100 mg twice daily) and gradually increase
  • Monitor blood levels (therapeutic range: 4-12 mcg/mL)
  • Monitor for side effects: dizziness, drowsiness, liver function abnormalities

• Oxcarbazepine (alternative first-line)

  • Better side effect profile than carbamazepine
  • Similar efficacy 1, 3

2. Second-Line/Add-on Medical Therapy:

If first-line therapy is partially effective or poorly tolerated, consider:

• Lamotrigine
• Gabapentin
• Pregabalin
• Baclofen
• Phenytoin 1, 3
• Botulinum toxin type A (as adjunctive therapy) 3, 5

3. Acute Exacerbations:

For severe breakthrough pain requiring hospital management:

• Intravenous fosphenytoin or lidocaine 3

4. Surgical Interventions:

Refer for surgical evaluation when:

• Pain is not adequately controlled with medications
• Side effects of medications are intolerable 3

Surgical options include:

• Non-ablative:

  • Microvascular decompression - recommended as first-line surgery for classical trigeminal neuralgia with demonstrated neurovascular contact 1, 3
  • Provides best rates of long-term pain relief and preservation of facial sensation 1

• Ablative procedures (when microvascular decompression is contraindicated):

  • Stereotactic radiosurgery (Gamma Knife) - good option for patients unable to tolerate general anesthesia 1, 6
  • Radiofrequency thermocoagulation
  • Glycerol rhizolysis
  • Balloon compression 1

Important Considerations and Pitfalls

1. Do not delay surgical referral when medical therapy is ineffective or poorly tolerated. Unlike other chronic pain syndromes, trigeminal neuralgia patients can achieve 100% pain relief with surgical intervention 1.

2. Beware of misdiagnosis:

   • Trigeminal neuralgia must be distinguished from other facial pain syndromes
   • Trigeminal autonomic cephalgias (SUNCT/SUNA) can mimic trigeminal neuralgia but have different treatment approaches 1

3. Monitor for adverse effects of carbamazepine:

   • Autoinduction occurs after 3-5 weeks of treatment
   • Blood monitoring is essential
   • Drug interactions are common 2

4. Consider secondary causes:

   • In patients over 50 with temporal pain, rule out giant cell arteritis which requires urgent treatment 1
   • Multiple sclerosis can present with trigeminal neuralgia

5. Surgical outcomes vary:

   • Microvascular decompression offers approximately 70% chance of being pain-free at 10 years 1
   • Ablative procedures have higher rates of facial sensory loss and pain recurrence 1

The management of trigeminal neuralgia requires a systematic approach starting with accurate diagnosis, first-line medical therapy, and timely surgical referral when indicated to optimize patient outcomes and quality of life.