In multivariate analysis, the odds of meningitis were threefold higher in patients admitted with trigeminal neuralgia than in matched controls without trigeminal neuralgia.
This is the first nationwide population-based study of the rare, chronic pain disorder to identify the prevalence of trigeminal neuralgia admissions in the United States and risk factors contributing to trigeminal neuralgia development.
“Our results affirm known associations between trigeminal neuralgia and comorbidities like multiple sclerosis, and they also identify meningitis as a novel risk factor for trigeminal neuralgia,” said investigator Megan Tang, BS, a medical student at the Icahn School of Medicine at Mount Sinai, New York City.
The findings were presented at the American Association of Neurological Surgeons (AANS) 2024 annual meeting.
Strong Clinical Risk Factors
Trigeminal neuralgia is a rare pain disorder involving neurovascular compression of the trigeminal nerve. Its etiology and risk factors are poorly understood. Current literature is based on limited datasets and reports inconsistent risk factors across studies.
To better understand the disorder, researchers used International Classification of Diseases (ICD)-9 codes to identify trigeminal neuralgia admissions in the National Inpatient Sample from 2016 to 2019, and then propensity matched them 1:1 to non-trigeminal neuralgia admissions based on demographics, socioeconomic status, and Charlson comorbidity index scores.
Univariate analysis identified 136,345 trigeminal neuralgia admissions or an overall prevalence of 0.096%.
Trigeminal neuralgia admissions had lower morbidity than non-trigeminal neuralgia admissions and a higher prevalence of non-White patients, private insurance, and prolonged length of stay, Ms. Tang said.
Patients admitted for trigeminal neuralgia also had a higher prevalence of several chronic conditions, including hypertension, hyperlipidemia, and osteoarthritis; inflammatory conditions like lupus, meningitis, rheumatoid arthritis, and inflammatory bowel disease; and neurologic conditions including multiple sclerosis, epilepsy, stroke, and neurovascular compression disorders.
In multivariate analysis, investigators identified meningitis as a previously unknown risk factor for trigeminal neuralgia (odds ratio [OR], 3.1; P < .001).
Other strong risk factors were neurovascular compression disorders (OR, 39.82; P < .001) and multiple sclerosis (OR, 12.41; P < .001). Non-White race (Black; OR, 1.09; Hispanic; OR, 1.23; Other; OR, 1.24) and use of Medicaid (OR, 1.07) and other insurance (OR, 1.17) were demographic risk factors for trigeminal neuralgia.
“This finding points us toward future work exploring the potential mechanisms of predictors, most notably inflammatory conditions in trigeminal neuralgia development,” Ms. Tang concluded.
She declined to comment further on the findings, noting the investigators are still finalizing the results and interpretation.
Ask About Meningitis, Fever
Commenting on the findings, Michael D. Staudt, MD, MSc, University Hospitals Cleveland Medical Center, said that many patients who present with classical trigeminal neuralgia will have a blood vessel on MRI that is pressing on the trigeminal nerve.
“Obviously, the nerve is bathed in cerebrospinal fluid. So, if there’s an inflammatory marker, inflammation, or infection that could be injuring the nerve in a way that we don’t yet understand, that could be something that could cause trigeminal neuralgia without having to see a blood vessel,” said Dr. Staudt, who was not involved in the study. “It makes sense, theoretically. Something that’s inflammatory, something that’s irritating, that’s novel.”
Currently, predictive markers include clinical history, response to classical medications such as carbamazepine, and MRI findings, Dr. Staudt noted.
“Someone shows up with symptoms and MRI, and it’s basically do they have a blood vessel or not,” he said. “Treatments are generally within the same categories, but we don’t think it’s the same sort of success rate as seeing a blood vessel.”
Further research is needed, but, in the meantime, Dr. Staudt said, “We can ask patients who show up with facial pain if they’ve ever had meningitis or some sort of fever that preceded their onset of pain.”
The study had no specific funding. Ms. Tang and coauthor Jack Y. Zhang, MS, reported no relevant financial disclosures. Dr. Staudt reported serving as a consultant for Abbott and as a scientific adviser and consultant for Boston Scientific.
A version of this article appeared on Medscape.com.