Study: Trigeminal Neuralgia Affects More Than 3% of Patients

Trigeminal neuralgia, a chronic pain condition characterized by shocks or burning sensations in the face, seems to be much more common among people with multiple sclerosis (MS) than in the general population, according to a review of published studies.

This condition also is more prevalent in women with MS than it is in men, although the reasons for this are not yet clear.

Understanding the prevalence of trigeminal neuralgia could improve pain management among people with MS, the researchers noted.

The study, “Prevalence of trigeminal neuralgia in multiple sclerosis: A systematic review and meta-analysis,” was published in the journal Multiple Sclerosis and Related Disorders.

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MS patients often experience neuropathic pain, which is caused by damage to the nerves that carry signals between the central nervous system (the brain and spinal cord) and the rest of the body.

Trigeminal neuralgia is facial pain associated with damage to the trigeminal nerve, which transfers sensations from the face to the brain. It is one of the most common neuropathic pain syndromes in MS patients, and can greatly affect their quality of life.

Pain caused by trigeminal neuralgia is typically described as a feeling resembling burning or an electric shock in the face that lasts from a few seconds to two minutes. Although the underlying mechanisms have not been completely explained, damage to the myelin sheath that protects the trigeminal nerve is thought to be at the root of the pain sensations in MS patients. Sometimes, a blood vessel pressing on the nerve can cause trigeminal neuralgia.

The prevalence of trigeminal neuralgia in MS is still largely unknown. While some studies report rates as low as 0.05%, others have shown it occurs in about one of 10 patients.

To shed more light on the actual prevalence of this pain condition, researchers in Iran set out to review data from several published studies that had reported the rate of trigeminal neuralgia in people with MS.

A total of 19 studies, published from 1995 to 2020, met the inclusion criteria. Most of these studies were conducted in Europe (11) and Asia (4); other regions included North America and South America.

Overall, a total of 30,348 MS patients were included in the analyses. Their ages ranged from 27.9 to 62.2 years. In the 11 studies that indicated mean disease duration, it ranged from six to 24 years.

Results showed that the estimated prevalence of the condition was 3.4% — a substantially higher proportion than that seen in the general population, where trigeminal neuralgia is estimated to affect 0.03%–0.3% of people, the researchers wrote.

However, a high level of heterogeneity, or variability in the data, was found among studies, with one reporting a prevalence of 0.1% and another of 9.7%. Further analysis showed that publication year, sample size, patient age, and disease duration, could not explain the variability.

Also, findings showed that the condition was more prevalent in women (3.8%) than in men (2.4%), which is “consistent with the literature,” the investigators wrote.

“The exact reasons for the high prevalence of [trigeminal neuralgia] in women are not clear. However, small trigeminal nerve volume in women, the influence of sex hormone, and the differences in gene expression have been suggested as reasons,” they added.

A few limitations of the study were noted by the team, including not reporting prevalence based on MS severity, disease duration, and age at MS onset, or the frequency of trigeminal neuralgia diagnosis before MS onset.

“Further studies are required to understand the features of [trigeminal neuralgia] among MS patients,” the team concluded.