13.1.1 Classical trigeminal neuralgia

Previously used term:
Tic douloureux.

Description:
Trigeminal neuralgia developing without apparent cause other than neurovascular compression.

Diagnostic criteria:
A. At least three attacks of unilateral facial pain fulfilling criteria B and C
B. Occurring in one or more divisions of the trigeminal nerve, with no radiation beyond the trigeminal distribution
C. Pain has at least three of the following four characteristics:

    1. recurring in paroxysmal attacks lasting from a fraction of a second to 2 min
    2. severe intensity
    3. electric shock-like, shooting, stabbing or sharp in quality
    4. precipitated by innocuous stimuli to the affected side of the face1

D. No clinically evident neurological deficit2
E. Not better accounted for by another ICHD-3 diagnosis.

Notes:
1. Some attacks may be, or appear to be, spontaneous, but there must be at least three that are precipitated in this way to meet this criterion.

2. Hypoaesthesia or hypoalgesia in the affected trigeminal region always indicates axonal damage. When either is present, there is trigeminal neuropathy and extensive diagnostic work-up is necessary exclude symptomatic cases. There are some patients with hyperalgesia in the painful region, which should not necessarily lead to a diagnosis of trigeminal neuropathy because it may reflect the patient’s increased attention to the painful side.

Comments:
The term classical (rather than primary) trigeminal neuralgia is used because, according to current evidence, 13.1.1 Classical trigeminal neuralgia is caused by neurovascular compression, most frequently by the superior cerebellar artery. Imaging (preferably MRI) should be done to exclude secondary causes and, in the majority of patients, to demonstrate neurovascular compression of the trigeminal nerve.

Many patients with 13.1.1 Classical trigeminal neuralgia have a memorable onset of pain.

13.1.1 Classical trigeminal neuralgia usually appears in the second or third divisions. The pain never crosses to the opposite side but it may rarely occur bilaterally. Following a painful paroxysm there is usually a refractory period during which pain cannot be triggered. When very severe, the pain often evokes contraction of the muscle of the face on the affected side (tic douloureux). Mild autonomic symptoms such as lacrimation and/or redness of the eye may be present.

The duration of pain attacks can change over time and become more prolonged as well as severe. They can result in psychosocial dysfunction, significantly impairing quality of life and often leading to weight loss.

Between paroxysms. most patients are asymptomatic. In the subform 13.1.1.2 Classical trigeminal neuralgia with concomitant persistent facial pain, there is prolonged background pain in the affected area.

13.1.1 Classical trigeminal neuralgia may be preceded by a period of atypical continuous pain termed pre-trigeminal neuralgia in the literature.