Trigeminal Neuralgia

Basics

Description

  • The trigeminal nerve innervates the face, oral mucosa, nasal mucosa, and cornea with its sensory fibers
  • Trigeminal nerve = Cranial nerve (CN) V
  • Synonym: Tic douloureux:
    • Tic = spasmodic muscular contraction
    • Douloureux = painful
  • Usually occurs in patients >50 yr of age
    • Most common age group is 50–60 yr
  • Females > males
  • Facial pain syndrome recognizable by history alone
  • Classical:
    • Paroxysmal attacks of unilateral (rarely bilateral) pain affecting 1 or more divisions of the trigeminal nerve
    • Has 1 of the following characteristics:
      • Superficial
      • Sharp
      • Stabbing pain
    • Precipitated from trigger areas or factors
    • Lasts for <1 s–2 min
    • Episodes are stereotyped in each individual
    • No clinically evident neurologic deficit
    • Not caused by another disorder
  • Symptomatic:
    • Same as above but a causative lesion (not vascular compression) is identified

Etiology

  • Mechanism of pain production remains controversial; accepted theory suggests:
    • Demyelination of CN, leading to ectopic stimulation and pain:
      • Demyelination caused by tortuous or aberrant vascular compression of nerve root
      • 80–90% of classical trigeminal neuralgia have compression
      • Superior cerebellar artery is the most common (75%)
      • Anterior inferior cerebellar artery (10%)
  • Secondary causes:
    • Herpes zoster
    • Multiple sclerosis
    • Space-occupying lesions:
      • Cerebellopontine angle tumor
      • Aneurysm
      • Arteriovenous malformation

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