Advanced Cases

From the EMDaily Archives: Refractory Trigeminal Neuralgia by Dr. Richard Byrne

A 34 year old female with a history of trigeminal neuralgia presented with a chief complaint of 5 days of severe, worsening paroxysms of pain in the left trigeminal nerve distribution. The pain was refractory to carbamazepine and gabapentin. Neurology was consulted and an unconventional therapy was recommended: 

  • Trigeminal neuralgia is a chronic facial pain syndrome characterized by paroxysms of severe, lancinating pain in the trigeminal nerve distribution: usually the maxillary or mandibular branches.
    • The pain is typically unbearable, having been described as “the worst pain a human can endure.” Before effective pharmacotherapy, patients would often resort to suicide.
  • First line therapy is carbamazepine at starting doses of 200 mg/day, titrated up as high as 1200 mg/day in divided doses.
  • Second line therapy is either gabapentin or lamotrigineBaclofen has been used as an add-on medication in refractory cases.
  • Severe pain exacerbations will often prompt patients to seek care in the ED and require opiates for acute relief.
  • Several case reports and case series have suggested intravenous phenytoin or fosphenytoin for abortive therapy, usually reporting complete or near complete relief of pain after infusion.
  • The patient received 1,000 mg of phenytoin over a 1.5 hour infusion. Reported pain decreased from 9/10 to 1/10 nearly immediately. She was discharged on oral oxcarbamazepine and baclofen with neurology follow-up.
  • Conclusion: Consider intravenous phenytoin or fosphenytoin for acute pain crises in trigeminal neuralgia patients.
    • Remember to infuse phenytoin no faster than 25-50 mg/min to avoid hypotension and bradycardia.

1. Cheshire, William. Fosphenytoin: An Intravenous Option for the Management of Acute Trigeminal Neuralgia Crisis.  Journal of Pain and Symptom Management 2001; 21(6): 506-510.

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