What are the typical features of trigeminal neuralgia?

Typical Features of 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, which has a profound effect on quality of life. 1

Key Clinical Characteristics

Pain Description

• Location: Unilateral, affecting one or more branches of the trigeminal nerve (most commonly the second and third divisions)
• Duration: Paroxysmal attacks lasting 2 seconds to minutes
• Quality: Sharp, shooting, electric shock-like, frightful
• Severity: Moderate to very severe
• Pattern: Distinct refractory period between attacks

Triggering Factors

• Light touch
• Washing face
• Exposure to cold wind
• Eating
• Brushing teeth
• Speaking
• Shaving

Associated Features

• Fear and depression if pain is severe
• Light touch-evoked pain
• Rarely sensory changes
• Patients may develop avoidance behaviors to prevent triggering pain

Diagnostic Considerations

Clinical Variants

1. Classical Type: Associated with neurovascular compression of the trigeminal nerve in or around the root entry zone 1
2. Type 2/Trigeminal Neuralgia with Concomitant Pain: Features more prolonged pain between the sharp shooting attacks 1
3. Secondary Trigeminal Neuralgia: Associated with underlying conditions such as:
   • Tumors (mostly benign)
   • Multiple sclerosis
   • Other structural lesions 1, 2

Diagnostic Imaging

• MRI is the preferred modality for investigating trigeminal neuralgia 1
• High-resolution trigeminal sequences should be included to detect:
  • Neurovascular compression
  • Underlying pathology (tumors, multiple sclerosis plaques)
  • Structural abnormalities 1

Management Approach

First-Line Pharmacotherapy

• Carbamazepine remains the primary drug of choice with approximately 75% of patients achieving initial symptom control 1, 2
• Oxcarbazepine is equally effective with fewer side effects 1

Second-Line Medications

• Lamotrigine
• Baclofen
• Gabapentin (especially when combined with ropivacaine)
• Pregabalin 1

Surgical Considerations

• Neurosurgical opinion should be sought early, especially when:
  • Side effects of medications become intolerable
  • Pain control becomes sub-optimal 1, 3

Surgical Options

1. Non-ablative: Microvascular decompression (MVD)

   • 70% chance of being pain-free at 10 years
   • Preserves facial sensation
   • Carries 0.4% mortality risk and 2-4% risk of hearing loss 1

2. Ablative procedures:

   • Radiofrequency thermocoagulation
   • Glycerol rhizotomy
   • Balloon compression
   • Gamma Knife radiosurgery
   • Approximately 50% chance of being pain-free for 4 years
   • Result in varying degrees of sensory loss 1

Common Pitfalls and Caveats

1. Misdiagnosis: Trigeminal neuralgia may be confused with:

   • Dental pain (toothache)
   • Temporomandibular disorders
   • Trigeminal autonomic cephalalgias (e.g., SUNCT/SUNA)
   • Atypical facial pain

2. Delayed Surgical Referral: Patients should be referred for surgical evaluation early in the disease course, not just after multiple medication failures 1, 3

3. Medication Side Effects: Carbamazepine and other anticonvulsants can cause significant side effects that may limit their long-term use 1

4. Inadequate Imaging: Failure to obtain appropriate MRI imaging may miss secondary causes of trigeminal neuralgia that require specific treatment 1

5. Quality of Life Impact: The profound effect on quality of life is often underestimated, with patients developing fear of triggering pain that can lead to malnutrition, weight loss, depression, and social isolation 1, 3

Proper recognition of these characteristic features allows for early diagnosis and appropriate management, significantly improving outcomes and quality of life for patients suffering from this excruciating condition.