Differentiating Trigeminal Neuropathy From Trigeminal Neuralgia

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Differentiating Trigeminal Neuropathy From
Trigeminal Neuralgia

• Does It Even Matter?
• Justin Sandall, D.O.
• Vanderbilt University Medical Center
• Department of Anesthesiology, CA-2

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Case Presentation

• 26 y/o female w/a history of chronic migraine HA,
  depression and hypothyroidism presents for
  evaluation of L sided facial pain. 
• She relates a history of migraines since the age
  of 11 occurred infrequently until beginning
  college in 2001 at which time they increased in
  frequency to 2-3x/month. 
• 1 year ago she had her typical migraine which
  "didn't go away."  She now has a constant,
  throbbing/boring pain in her L periorbital/frontal
  area with occ. radiation to the L maxilla. 
• She also has intermittent sharp, lancinating
  pains in thosesame areas. 
• Her pain is worsened with anxiety, working out,
  loud noises, heat and alleviated with application
  of cold, migraine medications and Lyrica. Mother
  has noticed L sided facial swelling.
• There is no association with brushing teeth,
  putting on makeup or wind on the face.  She
  denies changes in hearing, balance or
  coordination.  She also denies sensory changes,
  tearing, conjunctival effusion and ataxia. 
• No h/o trauma or HSV.

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Case Presentation

• MEDICATIONS  - Synthroid Oral Tablet 75 mcg 1
  tablet by mouth daily - Betaxolol 10mg PO twice
  daily - Zoloft 150mg PO daily - Migrelief 2
  tabs PO - Topamax 300mg OP daily - Ondansetron
  tab PO PRN - Indomethacin 25mg PO twice daily -
  Zomig Zmt 5mg PO twice daily - Lyrica 300mg -
  Kariva BC - Zyrtec 10mg

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Case Presentation

• Relevant Physical Exam
• PERRL, CN II-XII intact b/l, NTTP along
  trigeminal distribution w/o allodynia or
  hyperesthesia, no sensory deficits, TMJ NTTP b/l
• Relevant Imaging
• Previous work-up including CT and MRI unrevealing

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Trigeminal Neuralgia

• Most common pain syndrome referable to a cranial
  nerve.1
• Most common in adults gt 50 y/o, women slightly
  more than men2
• Classically, pain is described as an electric
  shocklike, stabbing, unilateral pain with abrupt
  onset and termination in distribution of
  trigeminal nerve usually V2/3.2,3
• Intervals between attacks are pain free
• Minimal or no sensory loss in the region of pain
• Precipitation from trigger areas or by certain
  daily activities, such as eating, talking,
  washing the face, or cleaning the teeth3
• Diagnosis is typically made by the history
• Imaging is often pursued to r/o other causes of
  facial pain /or to evaluate for MS, vascular
  compression of the trigeminal nerve etc.
• Typically, 80 of patients respond to medical
  therapy3
• 1st line therapy is carbamazepine2,3,5

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Trigeminal Neuralgia

• May target trigeminal nerve at various sites with
  nerve blocks if unresponsive to medical therapy
• Superficial V1/V2, gasserian ganglion
• If responsive to local anesthetic block, may
  pursue trigeminal neurolysis
• Most common target is the gasserian ganglion via
  the foramen ovale1
• Studies have all used patients w/classic
  trigeminal neuralgia
• Less premorbid depression/anxiety, more satisfied
  w/outcome, fewer side effect complaints, more
  willing to repeat procedure1
• Study by Taha and Tew in 1996 evaluated RF
  rhizotomy w/curved electrode, RF rhizotomy,
  glycerol rhizotomy, balloon compression, and
  posterior fossa exploration (microvascular
  decompression, partial trigeminal rhizotomy)4
• Showed initial pain relief to be 91-98 with
  success of procedure in 85-98 and pain
  recurrence in 15-54
• Glycerol rhizotomy had lowest initial pain
  relief, lowest procedure success and highest pain
  recurrence
• Complications of trigeminal neurolysis can be
  devastating and include anesthesia dolorosa, loss
  of corneal sensation, keratitis, dysesthesia1

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Trigeminal Neuropathy (included atypical
trigeminal neuralgia and atypical facial pain)

• Chronic or recurrent pain in the area of previous
  nerve injury, numbness, dysesthesias, and chronic
  burning sensations. Diagnostic evaluations rule
  out any other cause of pain.2
• More likely to have sensory loss or allodynia5
• Doesnt meet White and Sweet criteria2  
• The pain is paroxysmal.
• The pain is confined to the trigeminal
  distribution.
• The pain is unilateral.
• The bedside clinical sensory examination is
  normal.
• The pain may be provoked by light touch to the
  face (trigger zones)
• Significant clinical challenge because the
  symptoms of PTN respond poorly, if at all, to AED
  or surgical therapies commonly used in TN.1,2
• Neurolytic treatment may actually worsen pain in
  this subgroup
• More often associated with young, middle aged
  women and feelings of depression
• Motor cortex stimulation for trigeminal neuralgia
  seems promising 70 success rate compared to
  50 for central pain5

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Adapted from Essentials of physical medicine and
rehabilitation musculoskeletal disorders, pain,
and rehabilitation/ edited by Walter R.
Frontera, Julie K. Silver, Thomas D. Rizzo
Jr.2nd ed. Chapter 90.
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Case Resolution

• 26 y/o female with L sided facial pain in the
  setting of chronic migraine HA, h/o depression
  and hypothyroidism. Given the nature of her
  pain, her history of depression and migraine HA,
  her pain triggers or lack thereof and physical
  exam findings, this most likely is atypical
  facial pain secondary to trigeminal neuropathic
  pain in the V1/V2 distribution rather than
  classic trigeminal neuralgia.  It is important to
  make this distinction given that definitive
  treatment of trigeminal neuralgia (i.e.
  neurolytic tx) can actually worsen the pain of
  trigeminal neuropathy.  In addition, she almost
  certainly has a component of transformed migraine
  HA that is contributory thus one of our long-term
  goals will be to decrease the number of medicines
  she is on.1. Atypical facial pain  2.
  Trigeminal neuropathic pain in the V1V2
  distribution  3. Transformed migraine headache 
  4. H/o depression5. Hypothyroidism 
• Will schedule for superficial V1/V2 block and TPI
  and assess response.  Needs to be off
  indomethacin x7 days prior to procedure.  May
  benefit from Gasserian ganglion block and/or
  Stellate ganglion block down the road if not
  responsive to more conservative measures.  If
  responds well to the peripheral n. blocks, will
  use Botox for long-term control. Meanwhile

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References

• Jackson T, Gaeta R Neurolytic blocks revisited.
  Current Pain and Headache Reports. 2008, 127-13.
• Raj's practical management of pain/editors,
  Honorio T. Benzonet al..4th ed. Chapter 25.
• Essentials of physical medicine and
  rehabilitation musculoskeletal disorders, pain,
  and rehabilitation/ edited by Walter R.
  Frontera, Julie K. Silver, Thomas D. Rizzo
  Jr.2nd ed. Chapter 90.
• Taha JM, Tew JM Comparison of surgical
  treatments for trigeminal neuralgia reevaluation
  of radiofrequency rhizotomy. Neurosurgery 1996,
  38865-871
• McMahon Wall and Melzack's Textbook of Pain, 5th
  ed. Chapter 37

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