• Clinical science
  • Clinician

Trigeminal neuralgia (Tic douloureux…)

Summary

Trigeminal neuralgia, or tic douloureux, is a condition characterized by attacks of facial pain in the area of one or more branches of the trigeminal nerve. The pain is typically very severe in intensity, has a sharp, stabbing quality, and lasts for several seconds. Attacks can occur without provocation but are sometimes triggered by innocuous stimuli like chewing. It is a rare condition that typically manifests in patients above the age of 60 years and affects women more often than men. Trigeminal neuralgia is a clinical diagnosis. Neuroimaging (preferably MRI) is used for further classification. Classical trigeminal neuralgia (CTN) is caused by neurovascular compression of the trigeminal nerve root, while secondary trigeminal neuralgia (STN) is caused by an underlying condition (e.g., multiple sclerosis). If there is no identifiable cause, it is referred to as idiopathic trigeminal neuralgia (ITN). Anticonvulsants (especially carbamazepine) are the mainstay of therapy. Surgery may be indicated if pharmacological treatment is insufficient. Options include microvascular decompression (MVD) and transcutaneous procedures that aim to lesion sensory fibers of the trigeminal nerve root or ganglion.

Epidemiology

  • Sex: > (2:1)
  • Peak incidence: 60–70 years

References:[1][2]

Epidemiological data refers to the US, unless otherwise specified.

Classification

Clinical features

  • Unilateral facial pain: paroxysmal, severe shooting or stabbing (like an electric shock), followed by a burning ache
    • Lasts several seconds; (in rare cases, several minutes) and may occur up to 100 times per day
    • Typically shoots from mouth to the angle of the jaw on the affected side
    • Occurs either at rest or is triggered by movements such as chewing, talking, or touch (e.g., brushing teeth, washing face); becomes worse with stimulation
  • Facial spasms may occur.
  • Psychological distress: ranging from dysphoria to severe depression with suicidal tendencies
  • Usually progressive course

References:[2][4][5]

Diagnostics

Trigeminal neuralgia is a clinical diagnosis. MRI should be performed at least once in the patient's lifetime to evaluate for structural etiology.

Diagnostic criteria

  • All of the following criteria must be fulfilled: [3]
    • Recurring unilateral face pain in the area innervated by one or more divisions of the trigeminal nerve
    • Pain characteristics
      • Severe
      • Lasting no more than two minutes
      • Quality: sharp, shooting, stabbing, or electric shock-like
    • Triggered by innocuous stimuli in the area innervated by the affected trigeminal nerve divisions
    • Another ICDH-3 diagnosis does not better explain the symptoms.

Imaging

Additional investigations

  • Electrophysiologic trigeminal reflex measurement [9][10][11]
    • Indication: differentiation of CTN from STN (if MRI is not possible)
    • Procedure: The supraorbital, infraorbital, or mental nerve is stimulated electrically and the response recorded with surface electrodes.
    • Findings

Differential diagnoses

The differential diagnoses listed here are not exhaustive.

Treatment

Anticonvulsants are the mainstay of therapy in CTN and ITN. Surgery should be considered if there is an insufficient response to medical therapy or intolerable side effects. Treatment for STN is similar to that of CTN, with additional treatment for the underlying condition (e.g., multiple sclerosis). Specialists should be involved as early as possible to monitor and adapt therapy.

Medical therapy [12][10][13][5]

Chronic therapy

Acute exacerbation

  • Consider lidocaine infusion : Only under the direction of an experienced physician with continuous cardiac monitoring [10][14]
  • Further treatment options include: [14]
  • Opioids are usually not effective. [10]

Surgical therapy [12][10][13]

Indications

  • Insufficient response to medical therapy or intolerable side effects [13]
  • Risks and benefits in the individual patient must be carefully weighed.
  • Most procedures have only been investigated in small studies in patients with CTN, and the evidence for their efficacy in patients with STN is even more limited. [12][10]

Microvascular decompression (MVD) [12][10]

  • Indications: Initially established in patients with CTN and signs of neural compression, but may be considered in ITN and STN as well
  • Description
    • Major neurosurgical procedure that requires a high level of expertise
    • Following a suboccipital craniotomy, the blood vessel compressing the trigeminal nerve root is identified and separated from the nerve. A piece of sponge-like material may be placed between the blood vessel and nerve. [15]
    • Achieves the most sustained pain relief in comparison to other invasive treatments [13]
  • Complications include [13]

Percutaneous neuroablative procedures [13][5][10]

  • Description
    • Insertion of a trocar or needle through the foramen ovale to lesion sensory fibers in the trigeminal nerve root
    • Ablation via heat (thermocoagulation), pressure (balloon compression), or chemicals (glycerol injection)
  • Complications include
    • Sensory loss (in up to 50% of patients) [13]
    • Dysesthesia
    • Anesthesia dolorosa
    • Corneal numbness [16]
  • Comparison to MVD
    • Craniotomy is not necessary, resulting in lower periprocedural risk.
    • Lower risk of serious complications
    • Similar rates of initial pain relief (∼ 90%)
    • Lower long-term efficacy (recurrence of pain in around 50% after 5 years) [12]

Gamma knife radiosurgery [10][13]

  • Indications: Consider in patients who cannot undergo open surgery, e.g., due to frailty or those who are anticoagulated.
  • Description: Stereotactic application of high-intensity gamma rays to damage the trigeminal ganglion
    • Pain relief may be delayed (∼ 1 month).
  • Complications include:
    • Sensory loss
    • Paresthesia
    • Recurrence of pain in around 50% of patients 3 years after treatment [13]

Acute management checklist

  • Consult neurology.
  • MRI of the brain (if not yet performed)
  • Start pharmacologic therapy. [6]
  • Consider inpatient treatment for severe acute pain exacerbations and/or psychiatric comorbidities (e.g., thoughts of suicide).