Trigeminal neuralgia and its comorbidities: a nationwide disease trajectory study

ABSTRACT

There is a limited understanding of risk factors and comorbidities in trigeminal neuralgia, a disease characterized by paroxysms of severe unilateral facial pain and a higher incidence in women. We aim to identify temporally associated comorbidities involving trigeminal neuralgia by analyzing nationwide disease trajectories. Using data from 7.2 million unique individuals in the Danish National Patient Register between 1994 and 2018, each individual diagnosed with trigeminal neuralgia was compared with 10,000 matched controls to identify co-occurring diseases. The sequential disease associations were identified in sex-stratified disease trajectories. A Cox-regression analysis investigated whether treatment with carbamazepine or oxcarbazepine, as compared with gabapentin, pregabalin, or lamotrigine, was associated with stroke risk. Finally, we investigated the stroke polygenic risk score and its association with stroke incidence in a subset of genotyped individuals with trigeminal neuralgia. We included 7141 individuals with trigeminal neuralgia (64.2% female, mean age at diagnosis 58.7 years) and identified 18 diseases associated with subsequent trigeminal neuralgia. After diagnosis, trigeminal neuralgia was associated with 9 diseases, including ischemic stroke (relative risk 1.55). Carbamazepine or oxcarbazepine treatment increased the ischemic stroke risk (hazard ratio 1.78; 95% confidence interval 1.47-2.17); however, the polygenic risk of stroke showed no association. In the Danish population, a trigeminal neuralgia diagnosis is temporally associated with 27 diseases revealed in systematic disease trajectories. Trigeminal neuralgia itself and its first-line treatment, but not a stroke polygenic risk score, was associated with an increased risk of ischemic stroke indicating that vascular risk factors should be routinely assessed in individuals with trigeminal neuralgia.

Trigeminal Neuralgia Is a Dementia Risk Factor: A Retrospective Cohort Study

Background: Dementia, a worldwide public-health issue, is regarded as a disorder rather than a normal aging process. Trigeminal neuralgia (TN) is a chronic debilitating pain disorder that impairs daily activities. Both are most prevalent in females and in patients older than 50 years. Recent studies reveal that pain and dementia may have a reciprocal interaction with each other. Objective: In response, we estimated whether adults with TN have an increased dementia risk. Methodology: By means of Taiwan's National Health Insurance Research Database, between 1996 and 2010, 762 patients aged over 50 years in the TN group were matched with 3048 patients in the non-TN group at a ratio of 1:4. Kaplan-Meier method and Cox proportional hazard regression models were also used to determine the cumulative incidence and compare the hazard ratios of dementia in each group. Results: The incidence of dementia was higher in the TN group compared to the non-TN group. After adjusting for covariates, the TN group had a 4.47-fold higher risk of dementia compared to the non-TN group. Additionally, the impact of TN on dementia risk was larger in young-aged patients than in old-aged patients. As well, the age at the time of dementia diagnosis was younger in the TN group compared to the non-TN group. Conclusions: TN is a dementia risk factor. Given the lack of a curative therapy for dementia, early identification of TN patients may help to prevent dementia sequelae.

Stroke risk after ocular cranial nerve palsy - A systematic review and meta-analysis

BACKGROUND

Isolated ischemic ocular cranial nerve palsies (OCNP) involving the 3rd, 4th and 6th cranial nerves (CN) are prevalent conditions in ophthalmic practice. However, it is not clearly established whether such patients are at increased risk of stroke after onset of OCNPs.

METHODS

Medline, PubMed, Embase and Cochrane Central registers were systematically searched for eligible studies comparing isolated ischemic OCNPs against matched controls on the subsequent development of stroke with at least two years of follow up. Case reports and series were excluded. Appropriate studies were entered for meta-analysis to determine hazard ratios. Search and data extraction was completed on 22 Feb 2021. Random effect models were used to generate pooled hazard ratios (HRs) and 95% confidence intervals (CIs).

RESULTS

Three studies were suitable for meta-analysis (total n = 2,756 OCNP cases and 21,239 matched controls). The meta-analysis demonstrated a hazard ratio of 5.96 (4.20-8.46 95% CI) of subsequent stroke after isolated OCNP within the first year. The hazard ratio reduced to 3.27 (2.61-4.10 95% CI) after five years although remains raised at 2.49 (1.53-4.06 95% CI) up to 12 years. The highest risk was demonstrated with 3rd cranial nerve palsies. Two additional studies assessed the risk of stroke with newly diagnosed diabetics and compared OCNPs against lacunar stroke. These studies did not demonstrate a significant increased risk of stroke, although they may be statistically underpowered.

CONCLUSION

Ischemic OCNPs represent a significant risk factor for development of subsequent stroke in a similar magnitude to transient ischemic attack within the first year.

Surgical Management of Trigeminal Neuralgia Induced by Brainstem Infarct: A Systematic Review of the Literature

BACKGROUND

Although cases of trigeminal neuralgia (TN) induced by brainstem infarct have been reported, the neurosurgical literature lacks a comprehensive review for this subpopulation of patients. We present the first systematic review of the literature to discuss pathology, surgical management, and future directions for therapeutic innovation in this population.

METHODS

Our systematic review was conducted according to PRISMA guidelines. Resulting articles were screened for those that presented cases of TN associated with brainstem infarct.

RESULTS

A review of the literature identified 18 case reports of 21 patients with TN induced by brainstem infarct: 14 pontine infarcts and 7 medullary infarcts. Although many cases of ischemic brainstem lesions are caused by acute stroke, cerebral small vessel disease also plays a role in certain cases, and the relationship between these chronic lesions and TN is more likely to be overlooked. Furthermore, we found that reports of self-resolving TN pain after brainstem infarct is disproportionately biased, as most case reports published their data within the first few months after initial presentation. Reports with follow-up periods >13 months reported eventual pain recurrence that necessitated surgical intervention. Microvascular decompression was not sufficient to treat TN pain associated with concurrent neurovascular compression and brainstem infarct.

CONCLUSIONS

Brainstem infarcts affecting the trigeminal pathway represent an understudied pathologic cause of TN. Although the neurosurgical literature lacks a clear picture of the most efficacious interventions in this population, we are optimistic that this review will encourage further investigation into the best treatment for these patients.

Trigeminal Neuralgia

Trigeminal neuralgia is one of the most severe facial pains that patients can experience. This unpredictable, episodic pain, mostly unilateral in the distribution of the trigeminal nerve, results in recurrent shooting pain lasting for seconds to minutes. It is light touch provoked and therefore prevents patients from eating and touching their face, and so has a significant impact on quality of life. Patients often consult a dentist because it usually presents like dental pain. Dentists need to avoid irreversible dental treatment. Response to carbamazepine is good but tolerability is poor. Surgical options are available and are generally successful. Patients can gain further information from a patient support group, such as Trigeminal Neuralgia Association UK.

CPD/Clinical Relevance: Although rare, trigeminal neuralgia patients often present to dentists who therefore need to recognize it as a non-dental cause of pain in order to avoid irreversible dental treatment.

Application of Virtual Navigation with Multimodality Image Fusion in Foramen Ovale Cannulation

Objective

Idiopathic trigeminal neuralgia (ITN) can be effectively treated with radiofrequency thermocoagulation. However, this procedure requires cannulation of the foramen ovale, and conventional cannulation methods are associated with high failure rates. Multimodality imaging can improve the accuracy of cannulation because each imaging method can compensate for the drawbacks of the other. We aim to determine the feasibility and accuracy of percutaneous foramen ovale cannulation under the guidance of virtual navigation with multimodality image fusion in a self-designed anatomical model of human cadaveric heads.

Design

Five cadaveric head specimens were investigated in this study. Spiral computed tomography (CT) scanning clearly displayed the foramen ovale in all five specimens (10 foramina), which could not be visualized using two-dimensional ultrasound alone. The ultrasound and spiral CT images were fused, and percutaneous cannulation of the foramen ovale was performed under virtual navigation. After this, spiral CT scanning was immediately repeated to confirm the accuracy of the cannulation.

Results

Postprocedural spiral CT confirmed that the ultrasound and CT images had been successfully fused for all 10 foramina, which were accurately and successfully cannulated. The success rates of both image fusion and cannulation were 100%.

Conclusions

Virtual navigation with multimodality image fusion can substantially facilitate foramen ovale cannulation and is worthy of clinical application.

Enhancement in Tonically Active Glutamatergic Inputs to the Rostral Ventrolateral Medulla Contributes to Neuropathic Pain-Induced High Blood Pressure

Neuropathic pain increases the risk of cardiovascular diseases including hypertension with the characteristic of sympathetic overactivity. The enhanced tonically active glutamatergic input to the rostral ventrolateral medulla (RVLM) contributes to sympathetic overactivity and blood pressure (BP) in cardiovascular diseases. We hypothesize that neuropathic pain enhances tonically active glutamatergic inputs to the RVLM, which contributes to high level of BP and sympathetic outflow. Animal model with the trigeminal neuropathic pain was induced by the infraorbital nerve-chronic constriction injury (ION-CCI). A significant increase in BP and renal sympathetic nerve activity (RSNA) was found in rats with ION-CCI (BP, n = 5, RSNA, n = 7, p < 0.05). The concentration of glutamate in the RVLM was significantly increased in the ION-CCI group (n = 4, p < 0.05). Blockade of glutamate receptors by injection of kynurenic acid into the RVLM significantly decreased BP and RSNA in the ION-CCI group (n = 5, p < 0.05). In two major sources (the paraventricular nucleus and periaqueductal gray) for glutamatergic inputs to the RVLM, the ION-CCI group (n = 5, p < 0.05) showed an increase in glutamate content and expression of glutaminase 2, vesicular glutamate transporter 2 proteins, and c-fos. Our results suggest that enhancement in tonically active glutamatergic inputs to the RVLM contributes to neuropathic pain-induced high blood pressure.

Increased Risk of Stroke in Patients with Isolated Third, Fourth, or Sixth Cranial Nerve Palsies: A Nationwide Cohort Study

BACKGROUND AND PURPOSE

The aim of this nationwide cohort study was to evaluate whether the occurrence of isolated 3rd, 4th or 6th cranial nerve (CN) palsies is associated with a higher risk of ischemic stroke.

METHODS

This study utilized data from Taiwan Longitudinal Health Insurance Database during 1995-2012. Subjects aged 20 years or older who had isolated CN 3/4/6 palsies diagnosed by a neurologist or ophthalmologist between January 2000 and December 2011 were included. A set of propensity score matched, randomly sampled patients who had never been diagnosed with CN 3/4/6 palsies were extracted to constitute the control group (cases and controls = 1:4). All subjects were followed until death, loss due to follow-up or completion of the study. Cox proportional hazard regression model stratified by matched pairs was used to estimate the hazards ratio (HR) of ischemic stroke.

RESULTS

A total of 657 patients with isolated CN 3/4/6 palsies (61.1% male, mean age 54.8 years) were identified. Compared with control group, the patients with isolated CN 3/4/6 palsies exhibited an increased risk of ischemic stroke (CN3: adjusted HR 3.69 (95% CI 2.20-6.19); CN4: 2.71 (95% CI 1.11-6.64); CN6: 2.15 (95% CI 1.31-3.52)). The association between CN 3/4/6 palsies and ischemic stroke was detected in both separate subgroup and sensitivity analyses.

CONCLUSIONS

The patients with CN 3/4/6 palsies exhibited an increased risk of developing ischemic stroke. Therefore, isolated ocular motor nerves palsies appear to represent an unrecognized risk factor for ischemic stroke, and these require further confirmation and exploration.

Chronic periodontitis and the subsequent risk of trigeminal neuralgia: a 5-year follow-up study

AIM

This study set out to explore the possibility that chronic periodontitis (CP) may also be a condition that could potentially result in secondary or symptomatic trigeminal neuralgia (TN) by utilizing a population-based dataset and cohort study design in Taiwan.

MATERIALS AND METHODS

We included 110,104 subjects with CP in our study cohort, and randomly selected 110,104 subjects without a history of CP as a comparison cohort. We individually tracked each patient in this study for a 5-year period to identify those who received a subsequent diagnosis of TN.

RESULTS

The incidence rate of TN during the 5-year follow-up period was 4.40 (95% CI = 3.87-4.98) per 10,000 person-years for subjects with CP, and 2.60 (95% CI = 2.20-3.05) per 10,000 person-years in comparison subjects. Cox proportional analysis revealed that the adjusted hazard ratio (HR) of TN during the 5-year follow-up period for subjects with CP was 1.65 (95% CI = 1.34-2.03) times higher than that of comparison subjects. However, the study subjects who had undergone a gingivectomy or periodontal flap operation did not have a higher adjusted risk of TN than comparison subjects (HR = 0.93, 95% CI = 0.54-1.61).

CONCLUSION

Our study detected a greater risk for TN among patients with CP than matched comparison subjects.