Trigeminal neuralgia

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Trigeminal nerve anatomy.
Dermatome distribution of the trigeminal nerve: V1 (green), V2 (red), and V3 (yellow).
  • Also known as tic doulourex

Clinical Features

  • Paroxysms of severe unilateral pain in trigeminal nerve distribution lasting only seconds
  • Normal neuro exam
  • No pain between paroxysms
  • Variant with headache
  • More common in Middle aged women
  • Frequently triggered by minimal stimuli (e.g. light touch, gentle breeze)

Differential Diagnosis






Aseptic Meningitis

Facial paralysis


  • Sensory loss, bilateral involvement, and younger age (<40) are associated with a higher risk of secondary TN, but their absence does not rule out secondary TN
  • Consider CT/MRI in these patients to rule out structural etiology
  • <5% of patients have V1 distribution, examine carefully for zoster in these patients



  • First-line agent with 75% success rate initially
  • Proposed Mechanism: Decreases the response of neurons to peripheral stimulation
  • Started at 100mg one to two times per day
  • Increase by 100-200mg every 3 days
  • Usual maintenance dose is 400-800mg (rare >1500mg)
  • Metabolized by liver (cytochrome P450)
    • LFTs monitored on outpatient basis
  • Pain relief occurs within several hours to days (94% within 48 hours)
  • Target serum concentration is 24-43 μmol/L
    • If unsuccessful, phenytoin 200-400mg/day is used in combination

Other agents


  • Posterior fossa microvascular decompressive surgery
    • Approximately 50% of patients will require surgery
  • Successful in 70% of patients


  • Typically outpatient

See Also


  • J Pain Symptom Manage 2001; 21(6):506-510.