Trigeminal neuralgia

Clinical Findings

• Paroxysms of severe unilateral pain in trigeminal nerve distribution lasting only seconds
• Normal neuro exam
• No pain between paroxysms
• Variant with headache

Considerations

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 MRI in these patients to r/o structural etiology

<5% of patients have V1 distribution, examine carefully for zoster in these patients

Treatment

Phenytoin 250 mg IV to abort an acute attack

• Relief lasts from four hours to three days
•  Fosphenytoin seems to work similarly

Carbamazepine

• First-line agent with 75% success rate initially
• Proposed Mechanism: Decreases the response of neurons to peripheral stimulation
• Started at 100 mg one to two times per day
• Increase by 100-200 mg every 3 days
• Usual maintenance dose is 400-800 mg (rare > 1500 mg)
• Pain relief occurs within several hours to days (94% within 48
  hours)
• Target serum concentration is 24-43 μmol/L
  • If unsuccessful, phenytoin 200-400 mg/day is used in combination
• Other agents: Baclofen, Clonazepam, Valproic acid, Lamotrigine, Gabapentin, Oxcarbazepine, Topiramate
• Posterior fossa microvascular decompressive surgery
  • Approximately 50% of patients will require surgery 

Successful in 70% of patients16

Source

Tintinalli, UTD

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