Trigeminal Neuralgia

Question 1

The 3 branches of the Fifth Cranial Nerve

Answer 1

V1 - Opthalmic
V2 - Maxillary
V3 - Mandibular

Question 2

Causes of Trigeminal Neuralgia

Answer 2

Vascular compression (classic TN)

Other major cause (tumor, MS, trauma) = Secondary TN

Question 3

TN Presentation

Answer 3

recurrent paroxysms of pain in the distribution of any branch of the trigeminal nerve. The pain is usually described as burning, stabbing, sharp, penetrating, or electric shock–like and usually is on one side of the face.

Once a month to several times per day, but patient does not usually awaken from sleep due to the pain

Question 4

TN Trigger Zone

Answer 4

A characteristic feature of trigeminal neuralgia is the trigger zone, a small area of the skin or orobuccal mucosa that the patient can identify as the point that sets off an attack. Just a light touch may set off the trigger.

Question 5

TN Imaging

Answer 5

MRI/MRA can help distinguish classic from secondary.

Question 6

TN Differentials

Answer 6

MS
Headache
Tumor
Meningitis
Dental
Polyneuropathy

if alternative diagnoses are suspected, an autoimmune laboratory panel may be indicated. Trigeminal reflex testing has demonstrated that abnormal reflexes are associated with greater risk of secondary trigeminal neuralgia

Question 7

Specific Criteria for Diagnosis

Answer 7

Unilateral orofacial pain within the facial or intraoral CN V territory, paroxysmal in nature, with spasms of pain lasting from a fraction of a second to 2 minutes, with ability to trigger with typical maneuvers (touch, chewing, brushing teeth)

Question 8

TN Referral

Answer 8

Patient does not tolerate medications
Patient fails management with 3 medications

All TN should be initially referred for comprehensive exam and imaging

Question 9

TN Treatment

Answer 9

Anticonvulsants - titrate to the maximum therapeutic dose necessary to provide pain relief, and then titrate down to the lowest effective dose.

Question 10

Carbamazepine for TN

Answer 10

100-200mg daily, max 200-400mg

Liver risk!, Sodium Risk!, Hematology Risk!

Question 11

Oxcarbazepine for TN

Answer 11

300mg twice daily, max 600-1200mg twice daily

Liver risk!, Sodium Risk!, Hematology Risk!

Question 12

Second Line TN Meds

Answer 12

Baclofen 5-10mg three times daily, MAX 30mg three times daily
Lamotrigine 25-50mg daily, MAX 150-200mg twice daily
Phenytoin 100-300mg daily, MAX 300-500mg daily

Question 13

TN and MS

Answer 13

Use Gabepentin 100-300mg daily, MAX 300-600mg three daily

Or Misoprostol 200mcg three times daily, Max 600mcg per day – not for pregnancy

Question 14

TN Acute Attacks

Answer 14

May consider IV phenytoin, Botox injection, sumatriptan, IN lidocine

Question 15

What is the initial treatment for a patient who is diagnosed with trigeminal neuralgia and reports having paroxysms several times each day?

A combination of baclofen, lamotrigine, and phenytoin

Low doses of anticonvulsants with gradual increase as needed

Botox injections or intranasal lidocaine as needed

A high dose of carbamazepine with subsequent titration downward

Answer 15

Anticonvulsants are first-line treatments for trigeminal neuralgia; carbamazepine is started at the maximum therapeutic dose and titrated down to the lowest effective dose. Combinations may be needed if a single agent does not work. Botox / IN Lido is not the initial treatment.