13.1.1.2.1 Trigeminal neuralgia attributed to multiple sclerosis

Coded elsewhere:

13.13.1 Central neuropathic pain attributed to multiple sclerosis.

Description:

Trigeminal neuralgia caused by a multiple sclerosis (MS) plaque or plaques in the pons or trigeminal nerve root entry zone, and associated with other symptoms and/or clinical signs or laboratory findings of MS.

Diagnostic criteria:
  1. Recurrent paroxysms of unilateral facial pain fulfilling criteria for 13.1.1 Trigeminal neuralgia
  2. Both of the following:
    1. multiple sclerosis (MS) has been diagnosed
    2. an MS plaque at the trigeminal root entry zone or in the pons affecting the intrapontine primary afferents has been demonstrated by MRI, or its presence is suggested by routine electrophysiological studies1 showing impairment of the trigeminal pathways
  3. Not better accounted for by another ICHD-3 diagnosis.
Note:

Blink reflex or trigeminal evoked potentials.

Comments:

13.1.1.2.1 Trigeminal neuralgia attributed to multiple sclerosis occurs in 2-5% of patients with multiple sclerosis (MS), sometimes bilaterally. Conversely, MS is detected in only 2-4% of cases of 13.1.1 Trigeminal neuralgia. Symptoms of trigeminal neuralgia are rarely a presenting feature of MS.

The lesion in the pons affects the intrapontine central terminals of the trigeminal afferents projecting to the trigeminal brainstem nuclei. Pontine lesions affecting the second order neurones of the trigeminothalamic tract usually lead to non-paroxysmal pain and/or dysaesthesias and should be classified as 13.13.1 Central neuropathic pain attributed to multiple sclerosis.

Some patients with MS are found to have neurovascular compression of the trigeminal root. It is thought that MS increases the susceptibility of the nerve root to the effects of compression, leading more readily to painful paroxysms.

Patients with 13.1.1.2.1 Trigeminal neuralgia attributed to multiple sclerosis benefit less from pharmacological and surgical interventions than those with 13.1.1.1 Classical trigeminal neuralgia.