Trigeminal neuralgia: Difference between revisions

 
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==Background==
==Background==
[[File:Gray778.png|thumb|Trigeminal nerve anatomy.]]
[[File:Gray784.png|thumb|Dermatome distribution of the trigeminal nerve: V1 (green), V2 (red), and V3 (yellow).]]
*Also known as tic doulourex


==Clinical Features==
==Clinical Features==
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==Evaluation==
==Evaluation==
*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
*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
*Consider [[head CT|CT]]/[[brain MRI|MRI]] in these patients to rule out structural etiology
*<5% of patients have V1 distribution, examine carefully for [[zoster]] in these patients
*<5% of patients have V1 distribution, examine carefully for [[zoster]] in these patients


==Management==
==Management==
===[[Phenytoin]]===
*250mg IV to abort an acute attack
*Relief lasts from four hours to three days
*[[Fosphenytoin]] seems to work similarly


===[[Carbamazepine]]===
===[[Carbamazepine]]===
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*Increase by 100-200mg every 3 days  
*Increase by 100-200mg every 3 days  
*Usual maintenance dose is 400-800mg (rare >1500mg)  
*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)  
*Pain relief occurs within several hours to days (94% within 48 hours)  
*Target serum concentration is 24-43 μmol/L  
*Target serum concentration is 24-43 μmol/L  
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===Other agents===
===Other agents===
*[[Baclofen]], [[clonazepam]], [[valproic acid]], [[lamotrigine]], [[gabapentin]], Oxcarbazepine, [[topiramate]]
*[[Baclofen]], [[clonazepam]], [[valproic acid]], [[lamotrigine]], [[gabapentin]], [[oxcarbazepine]], [[topiramate]]


===Surgery===
===Surgery===

Latest revision as of 11:31, 7 August 2022

Background

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

Headache

Common

Killers

Maimers

Others

Aseptic Meningitis

Facial paralysis

Evaluation

  • 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

Management

Carbamazepine

  • 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

Surgery

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

Disposition

  • Typically outpatient

See Also

References

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