5 Qs on the Treatment of Trigeminal Neuralgia

Question 1: Which of the following is not included in the American Academy of Neurology (AAN) definition of TN?

A. Abrupt onset of pain
B. Pain triggered by movement
C. Pain lasting a few seconds to 2 minutes
D. Pain that always affects both sides of the face

The AAN defines TN as pain restricted to one or more divisions of the trigeminal nerve. The pain is characterized as abrupt in onset, lasting a few seconds to 2 minutes maximum, and triggered by movements or innocuous mechanical stimuli. Except for TN associated with multiple sclerosis, in most cases pain is confined to one side of the face. Pain can be either paroxysmal or continuous.

Source: Cruccu G, Finnerup NB, Jensen TS, et al. Trigeminal neuralgia: New classification and diagnostic grading for practice and research. Neurology. 2016;87:220-228.

Question 2: Classical TN is caused by:

A. Compression of the trigeminal nerve root
B. Tumor
C. Multiple sclerosis
D. All of the above

The AAN classifies TN according to 3 etiologic categories. In idiopathic TN, the cause cannot be identified. Compression of the trigeminal nerve root is considered to be the cause of classical TN. Secondary TN is caused by major neurological diseases like multiple sclerosis or tumors of the cerebellopontine angle.

Source: Cruccu G, Finnerup NB, Jensen TS, et al. Trigeminal neuralgia: New classification and diagnostic grading for practice and research. Neurology. 2016;87:220-228.

Question 3: In TN, pain is distributed along branches of the trigeminal nerve. Which of the following is not usually affected by TN?

A. Posterior third of the scalp
B. Posterior part of external ear
C. Angle of the mandible
D. All of the above

In TN, pain is distributed along the 3 branches of the trigeminal nerve (ophthalmic, maxillary, and mandibular) and can extend to the entire face and forehead (with the exception of the angle of the mandible), the oral cavity, and the anterior two-thirds of the scalp. Pain does not extend to the posterior third of the scalp, the posterior part of the external ear, or the angle of the mandible, which are innervated by cervical nerves. Pain also does not extend to the back of the tongue or the throat, which is innervated by the glossopharyngeal nerve.

Source: Cruccu G, Finnerup NB, Jensen TS, et al. Trigeminal neuralgia: New classification and diagnostic grading for practice and research. Neurology. 2016;87:220-228.

Question 4: Triggered pain is of high diagnostic value in TN and always occurs at the site of stimulation.

A. True
B. False

Triggered pain is included in the AAN definition of TN. Pain can be triggered by something as innocuous as light touch or a whiff of air. Other activities, like shaving, applying makeup, brushing teeth, eating, drinking, talking, or smiling may also trigger pain. However, triggered pain may not always occur at the site of initial stimulation. Patients may also describe pain as radiating in quality.

Source: Cruccu G, Finnerup NB, Jensen TS, et al. Trigeminal neuralgia: New classification and diagnostic grading for practice and research. Neurology. 2016;87:220-228.

Question 5: Which of the following is considered first-line treatment for TN?

A. Amitriptyline
B. Carbamazepine
C. Oxcarbazepine
D. B and C

American and European guidelines consider carbamazepine and oxcarbazepine first line treatments for TN. Both are considered the most effective pharmacotherapy for TN, and decrease pain in about 90% of patients.^{1, 2} Amitriptyline is a tricyclic antidepressant used in the treatment of diabetic peripheral neuropathy.

Sources: 
1. Gronseth G, Cruccu G, Alksne J, et al. Practice parameter: The diagnostic evaluation and treatment of trigeminal neuralgia (an evidence-based review). Report of the Quality Standards Subcommittee of the American Academy of Neurology and the European Federation of Neurological Societies. Neurology. 2008;71:1183–1190.

2. Cruccu G, Gronseth G, Alksne J, et al. AAN-EFNS guidelines on trigeminal neuralgia management. Eur J Neurol. 2008;15:1013–1028.