Trigeminal Neuralgia Lesions Manifest Years Before Symptom Onset in MS

Trigeminal neuralgia (TN) culprit lesions are present years before the onset of TN symptoms among patients with multiple sclerosis (MS), according to evidence from a retrospective case series published in the Journal of Neurology, Neurosurgery & Psychiatry.

Around 5% of patients with MS develop TN, which is associated with debilitating pain and often requires treatment by multiple modalities including surgery. The understanding of the biological mechanism of TN is limited, but one hypothesis is that MS lesion formation or demyelination of the trigeminal tract contribute to symptoms.

For this study, researchers retrospectively reviewed records at the University of California San Francisco MS and Neuroinflammation Center of patients (N=26) who developed TN.

The study population comprised patients with a mean age of 56±13 years at TN symptom onset and 65% were women. The patients reported right-sided TN (n=15) or left-sided TN (n=11) and a total of 3 patients also had sensory loss of the affected side’s trigeminal distribution.

All but 1 patient had more than 2 magnetic resonance imaging (MRI) results to review.

Most patients (n=23) were found to have a probable TN culprit lesion observed in previous MRI scans. The average latency between TN lesion at MRI and TN symptom onset was 5.0±4.0 years, with a maximum latency of 15.9 years.

Within 14 days of symptom onset, a correlative lesion was observed at MRI.

The prevalence of progressive MS was 57% and conversion to secondary progressive MS occurred an average of 6±7 years prior to TN symptom onset.

Stratified by MS subtype, the time from MRI lesion to TN symptom onset was lower for patients with relapsing-remitting MS (mean, 2.6 years) compared with secondary progressive MS (mean, 5.47 years; P =.047).

At the onset of TN symptoms, 70% of patients were receiving disease-modifying treatments, 92% of patients used chronic TN pain medications, and 35% of patients ultimately underwent surgical intervention for TN.

The major limitation of this study was that MRIs were acquired using different techniques and on differing schedules.

Overall, the findings suggest that TN lesions can appear years prior to symptom onset in patients with MS, which is suggestive of alternative explanations that typical relapses, the researchers noted. They concluded that “This phenomenon may hint at alternative pathophysiology of progressive MS in comparison to relapsing-remitting MS.”