Module 8.15 - Trigeminal Neuralgia

Question 1

What is Trigeminal Neuralgia?

Answer 1

Inflammation, degeneration or pressure on the trigeminal nerve, Cranial Nerve V, which causes sharp, paroxysmal intermittent pain along trigeminal nerve and its branches.

Question 2

What causes Trigeminal Neuralgia?

Answer 2

• The Trigeminal nerve is one of 12 pairs of nerves attached to the brain. It has 3 branches that conduct sensations from the upper, middle and lower portions of the face, as well as the oral cavity, to the brain (see diagram below).
• Trigeminal neuralgia is associated with many conditions, multiple sclerosis, and nerve compression from a tumor, arteriovenous malformations, sinus surgery, oral surgery, stroke or facial trauma.

Question 3

What are the 2 types of trigeminal neuralgia?

Answer 3

A. Type 1: typical or ‘classic’ form of the disorder; extreme, sporadic, sudden burning or shock-like facial pain lasting from a few seconds to as long as 2 minutes per episode.

B. Type 2: ‘atypical’ form of the disorder; characterized by constant aching, burning, stabbing pain of somewhat lower intensity than Type I

Question 4

Describe the etiology for trigeminal neuralgia

Answer 4

A. Idiopathic

B. Affects 10 out of 100,000 persons annually

C. Increased incidence after age 50 years

D. Both genders are affected, female > male

E. Pain occurs in paroxysms and may last for hours

F. Right side is most often affected

G. May be triggered or precipitated by brushing the teeth, chewing and exposure to wind or cold.

Question 5

What are the subjective/physical exam findings associated with trigeminal neuralgia?

Answer 5

A. Pain varies, depending on type of TN

B. May affect small area of face or may spread.

C. Pain rarely occurs at night, when the affected individual is sleeping.

D. Attacks stop for periods of time and then return and can be progressive in nature.

E. Symptoms tend to be unilateral

F. Neurological exam is normal, except a sensory deficit may be found with CN V nerve on the affected side.

Question 6

What laboratory/diagnostic tests are used to diagnose trigeminal neuralgia?

Answer 6

NOTE * TN diagnosis is based primarily on the person’s history and description of symptoms, along with results from physical and neurological exams. Other disorders that cause facial pain must be ruled out before TN is diagnosed. Some disorders that cause facial pain include post herpetic neuralgia, cluster headache, TMJ disorder, etc.

A. CT to rule out neoplasm

B. MRI for cranial nerve V abnormalities

C. ESR to rule out temporal arteritis

Question 7

How do manage a patient with trigeminal neuralgia?

Answer 7

A. Anti-convulsant medicines- used to block nerve firing; generally effective in treating TN1, but less effective in TN2.

• 1. Carbamazepine (Tegretol) 100-1200mg/day NOTE* Monitor liver enzymes and serum drug concentrations; caution for potential drug-drug interactions in the elderly; use lowest effective dose.
• 2. If unable to tolerate Carbamazepine, then phenytoin (Dilantin) 300-600mg/day, NOTE* Monitor drug levels; many drug-drug interactions.
• 3. Lamotrigine (Lamictal) 100-400mg/day

B. Adjunctive therapy with baclofen, 5-20mg, up to four times daily (maximum 80mg/day)

C. Consider neurosurgical consultation for possible exploration for patients who fail to respond to pharmacological management.