The association between Bell's palsy and rheumatoid arthritis: A longitudinal study

Bell's palsy was associated with TRPV2 downregulation of Schwann cell by cold stress

OBJECTIVE

Epidemiological and clinical studies have shown that sharp changes in the ambient temperature are associated with the occurrence and development of Bell's palsy. However, the specific pathogenesis of peripheral facial paralysis remains nebulous. This study investigated the effect of cold stress on transient receptor potential cation channel subfamily V member 2 (TRPV2) secretion by Schwann cells and its role in Bell's palsy.

MATERIALS AND METHODS

Schwann cell morphology was observed using transmission electron microscopy (TEM). Cell proliferation, apoptosis and cell cycle were analysed using CCK8 and flow cytometry. ELISA, Reverse transcription-quantitative PCR, western blotting and immunocytochemical fluorescence staining were used to detect the effects of cold stress on TRPV2, neural cell adhesion molecule (NCAM) and nerve growth factor (NGF) expression in Schwann cells.

RESULTS

Cold stress resulted in a widening of the intercellular space, and the particles on the membrane showed different degrees of loss. Cold stress may cause Schwann cells to enter a cold dormant state. ELISA, RT-qPCR, western blotting and immunocytochemical fluorescences staining indicated that cold stress inhibited the expression of TRPV2, NCAM, and NGF.

CONCLUSIONS

Drastic temperature difference between cold and heat can downregulate TRPV2 and the secretome of Schwann cells. The imbalance of Schwann cell homeostasis under such stress may contribute to nerve signalling dysfunction leading to the development of facial paralysis.

Association between Influenza Vaccination and the Risk of Bell's Palsy in the Korean Elderly

Previous studies have shown controversial results on the risk of Bell’s palsy after influenza vaccination. Since the antigenic components of influenza vaccine can vary from season to season, continuous safety monitoring is required. The aim of the present study was to determine whether there was an increased risk of Bell’s palsy in the elderly after influenza vaccination between the 2015/2016 and 2017/2018 flu seasons. This study included the elderly who received influenza vaccinations for three flu seasons using a large-linked database of vaccination registration data from the Korea Disease Control and Prevention Agency and the National Health Insurance Service claims data. We used a self-controlled risk interval design with a risk interval of 1 to 42 days and a control interval of 57 to 98 days postvaccination and calculated the incidence rate ratio. To ensure the robustness of the results, sensitivity analyses were also carried out with different risk and control intervals. Of 4,653,440 elderly people who received the influenza vaccine, there was no statistically significant increase in the risk of Bell’s palsy (IRR: 0.99, 95% CI: 0.92–1.07). Similar results were found in analysis results for each season and the results of the sensitivity analyses excluding the 2017/2018 season. In conclusion, we found no evidence of an increased risk of Bell’s palsy after influenza vaccination. The results of our study provide reassurance about the safety of the influenza vaccine NIP program. However, it is necessary to continuously monitor the risk of Bell’s palsy during future flu seasons.

Increased risk of ischemic stroke in patients with Bell's palsy: A longitudinal follow-up study using a national sample cohort

OBJECTIVE

To investigate the association between Bell's palsy and stroke according to the different types of stroke, using a sample cohort based on the national Korean population.

METHODS

Individuals aged ≥ 20 years were collected from the Korean National Health Insurance Service National Sample Cohort between 2002 and 2013. We extracted the data for Bell's palsy patients (n = 3658) and 1:4 matched controls (n = 14,632) and analyzed the occurrence of hemorrhagic or ischemic stroke in both groups. Matching was performed on the basis of age, gender, income, and region of residence. For Bell's palsy, we included only participants who received the diagnosis (ICD-10 code, G510) 2 or more times via ambulatory visits for the same episode with steroid treatment. Patient admission histories were used to identify occurrences of hemorrhagic stroke (I60, I61 and I62) and ischemic stroke (I63). Adjusted hazard ratios were calculated using stratified Cox proportional hazard models for the Charlson comorbidity index and 95% confidence intervals (CIs). For the subgroup analyses, we divided the participants by age, sex, and each time period after the onset of Bell's palsy (≤1 year, 1 to 2 years, 2 to 3years, > 3years).

RESULTS

The risk of ischemic stroke was significantly increased in Bell's palsy patients compared to that in the controls (adjusted HR = 1.74, 95% CI = 1.38-2.19, P < 0.001). In the subgroup analyses, a significant association between two clinical disorders was observed in patients aged ≥ 50 years old, regardless of gender. The risk of ischemic stroke was significantly increased, especially within 2 years after Bell's palsy. In contrast, the risk of hemorrhagic stroke was not significantly increased.

CONCLUSION

There is an association of Bell's palsy with ischemic stroke but not with hemorrhagic stroke.

Is septal deviation associated with headache?: A nationwide 10-year follow-up cohort study

To investigate the potential relationship between septal deviation (SD) and headache using nationwide representative cohort sample data.This study used a nationwide cohort sample from the Korean National Health Insurance Service database. The cohort sample was composed of 1 million patients, which is obtained by propensity score matching from 2002 to 2013. There were 9171 individuals in the SD group and 28243 in the control or no SD group. The Kaplan-Meier survival analysis, the log-rank test, and Cox proportional hazard regression analysis were used to calculate the incidence, survival curve, and hazard ratio of headache for each group.There were no statistically significant differences in sex (P = .7708), age (P = .991), residential area (P = .9626), or socioeconomic status (P = .9982) between the 2 groups. The survival curve between SD and control or no SD showed a statistically significant difference. The adjusted hazard ratio for headache incidence during the 10-year follow-up period of the SD group was 1.37 (95% CI: 1.31-1.43).This cohort study suggests that SD is associated with headache. Therefore, these findings suggest that septoplasty can be considered as 1 of the treatment option in SD patients with headache.