Trigeminal Neuralgia


Trigeminal Neuralgia, Tic Douloureux

  • Epidemiology
  1. Incidence: 15,000 new cases per year in U.S. (3.4 women or 5.9 men per 100,000 per year)
    1. Incidence in UK as high as 26.8 per 100,000, and 12.6 per 100,000 in Netherlands (but criteria vary)
    2. Primary care physicians may see a few cases during their entire practice career
    3. Incidence in Multiple Sclerosis patients: 1-2%
  2. Onset after age 40 years in 90% of cases
    1. Mean age of onset 50 years old, with a peak at age 60 to 70 years
    2. Incidence increases to 45.2 per 100,000 in men over age 80 years old
  3. More common in women by ratio of 2:1
  • Risk Factors
  1. Multiple Sclerosis (present in 2-4% of Trigeminal Neuralgia cases, RR 20)
    1. Consider in younger patients (20-30 years old), especially with other neurologic involvement
    2. Outside of Multiple Sclerosis, Trigeminal Neuralgia is typically a condition of older patients (see above)
  2. Cerebrovascular Accident
  3. Hypertension in women
  • Pathophysiology
  1. Related to Trigeminal Nerve demyelination
    1. Demyelination due to compression from local structures (esp. Superior Cerebellar Artery)
    2. Demyelinated fibers are more prone to ephaptic conduction
      1. Light touch impulses transmit to nearby pain fibers
  2. Most common site at cerebellopontine nerve root area
  3. Effects all branches of the Trigeminal Nerve (Right side is more commonly involved)
    1. Maxillary branch is most commonly involved
    2. Ophthalmic branch is least commonly involved
  • Symptoms
  1. Facial pain in Trigeminal Nerve distribution
    1. Recurrent paroxysms of sharp, stabbing or lancinating pain
  2. Distribution
    1. Maxillary and mandibular branches of the Trigeminal Nerve (CN 5) are most commonly affected
    2. Each attack is unilateral (may alternate sides in up to 3-5% of cases)
  3. Characteristics
    1. Lancinating or stabbing pain that is severe and intense
    2. Electric shock type pain
    3. Facial spasms related to paroxysms of pain (Tic Douloureux)
  4. Timing
    1. Each attack lasts for seconds to minutes
    2. Attacks may occur as often as multiple times daily (as many as 100/day) or as infrequently as monthly
    3. Attacks become more frequent and severe over time (and more refractory to medication)
    4. Attacks are rare during sleep
    5. Remissions of more than 6 months occur in 50% of patients
  5. Triggers
    1. Washing face
    2. Tooth Brushing
    3. Cold exposure
    4. Chewing
    5. Trigger Zones (pathognomonic for Trigeminal Neuralgia)
      1. Small areas in the region of the nose and mouth
      2. Light touch or other minimal stimulation in these zones triggers an attack
  • History
  • Red Flags suggesting secondary cause or alternative diagnosis
  1. Abnormal findings on Neurologic Examination or on examination of head and neck (e.g. intracranial lesion)
  2. Age under 40 years old
  3. Pain lasts longer than 2 minutes
  4. Bilateral pain during a single attack
  5. Vision change, Hearing change or Vertigo
  6. Findings suggestive of Multiple Sclerosis (e.g. Ataxia, unilateral Vision change)
    1. Multiple Sclerosis is often comorbid with Trigeminal Neuralgia
  • Examination
  1. Evaluate for focal findings suggestive of a secondary cause or alternative diagnosis
  2. Specific focal areas of examination (abnormalities suggest alternative diagnosis)
    1. Temporomandibular Joint
    2. Facial Muscle Strength and symmetry
    3. Corneal Reflex
    4. Trigeminal NerveSensation (normal in Trigeminal Neuralgia)
      1. Trigger Zone presence is pathognomonic for Trigeminal Neuralgia (see above)
  • Diagnosis
  • Classical Trigeminal Neuralgia (Primary Trigeminal Neuralgia)
  1. Paroxysmal attacks localized to the Trigeminal Nerve
  2. Duration less than 2 minutes
  3. Characteristics (at least one must be present)
    1. Precipitated by triggers (e.g. Trigger Zones)
    2. Sharp, stabbing, intense pain
  4. Attacks are stereotypical for individual patients
  5. No neurologic clinical findings or other findings suggesting as secondary condition
  • Diagnosis
  • Atypical or Symptomatic Trigeminal Neuralgia (Type II or Trigeminal Neuralgia with concomitant pain)
  1. May be secondary to other conditions (consider secondary cause evaluation)
  2. Similar to classical Trigeminal Neuralgia with the following EXCEPTIONS
    1. Aching, lower level pain may persist between episodes for up to 50% of the time
  • Imaging
  1. Head MRI Indications
    1. Indicated in most cases of Trigeminal Neuralgia at onset
    2. Intracranial lesions are present in up to 10% of cases
  • Diagnostics
  1. Trigeminal reflex testing (via EMG testing)
    1. Differentiates classic from symptomatic Trigeminal Neuralgia with high efficacy
    2. Cruccu (2006) Neurology 66:139-41 [PubMed]
  • Management
  • General
  1. Neurology referral
    1. Evaluate for comorbid conditions (Multiple Sclerosis, Intracranial Lesions)
  • Management
  • Seizure medications (examples)
  1. Carbamazepine (Most studied)
    1. Typical effective dosage: 200-800 mg/day divided 2-3 times daily
    2. Longterm failure rate approches 50% after 5-10 years of continuous use
  2. Oxcarbazepine (Trileptal)
    1. Effective for pain reduction and fewer side effects than Carbamazepine, but less effective in the longterm
  3. Baclofen (Lioresal)
    1. Typical effective doses: 10-80 mg/day
    2. Consider in Multiple Sclerosis patients with Trigeminal Neuralgia
  4. Agents with unknown effectiveness (inadequate studies as of 2016)
    1. Phenytoin (Dilantin)
    2. Gabapentin (Neurontin)
    3. Topiramate (Topamax)
    4. Lamotrigine (Lamictal)
  5. References
    1. Delzell (1999) Arch Fam Med 8(3): 264-8 [PubMed]
  • Management
  • Symptomatic therapies
  1. Topical Capsaicin
  2. Intranasal Lidocaine (for second Trigeminal Nerve branch)
  3. Acupuncture is ineffective in Trigeminal Neuralgia
    1. Millan-Guerrero (2006) Headache 46(3): 532 [PubMed]
  • Management
  • Surgical
  1. Percutaneous Methods (non-invasive but short lasting)
    1. Glycerol injection
    2. Gamma Knife
    3. Radiofrequency thermocoagulation
      1. Effective, but risk of facial numbness and Corneal insensitivity
    4. Oturai (1996) Clin J Pain 12(4):311-5 [PubMed]
  2. Invasive Surgical Techniques (posterior fossa exploration)
    1. Microvascular decompression (Most effective, duration of 10 years in 70% of cases)
    2. Preferred over sterotactic radiosurgery
    3. Risk of unilateral Hearing Loss in 5% of cases
    4. Hai (2006) Neurol India 54(1):53-6 [PubMed]
    5. Tronnier (2001) Neurosurgery 48(6): 1261-8 [PubMed]
  • Complications
  1. Major Depression and Suicidality (due to severity of pain and incapacity)
  • Course
  1. Remission is typical (>50% of patients) for at least 6 months