Trigeminal cold receptors and airflow perception are altered in chronic rhinosinusitis.

BACKGROUND: In chronic rhinosinusitis (CRS), nasal obstruction can often be explained by anatomical deformities, polyps, or congested nasal mucosa. However, in cases with little deformity or inflammation, perceived nasal obstruction may result from reduced airflow perception caused by an alteration of the intranasal trigeminal system. The aim of this study was to assess this association. METHODOLOGY: We performed a prospective case-control study of 15 CRS patients, 18 patients with a deviated nasal septum (DNS) and 16 healthy controls. We assessed olfactory function using the Sniffin' Sticks test and Visual Analog Scales (VAS). We used the Trigeminal Lateralization Task (TLT) with eucalyptol and cinnamaldehyde to examine intranasal trigeminal function. Further, we assessed nasal patency with Peak Nasal Inspiratory Flow and VAS. Finally, we measured protein levels of trigeminal receptors (TRPM8, TRPA1 and TRPV1) and inflammatory markers (IL-13, INF-y and eosinophils) in CRS and DNS patients' mucosal biopsies using Western Blots. RESULTS: CRS patients had significantly lower olfactory function than DNS and healthy controls. They also had significantly lower TLT scores for eucalyptol than both other groups. CRS patients had significantly lower nasal patency than controls; for DNS patients this was limited to subjective measures of nasal patency. In line with this, CRS patients exhibited significantly higher levels of sTRPM8-18 than DNS patients. CONCLUSIONS: Intranasal trigeminal function is decreased in CRS patients, possibly due to the overexpression of short isoforms of TRPM8 receptors.

Trigeminal impairment in treatment-refractory chronic nasal obstruction.

BACKGROUND: Patients with anatomically unexplained, chronic nasal obstruction (CNO) that is refractory to medical treatment pose a challenge for clinicians. A surgical solution, addressing mechanical obstacles, is unsuited for these patients. CNO may result from disrupted airflow perception due to activation of the intranasal trigeminal system; therefore, aim of this study is to evaluate if intranasal trigeminal function of these CNO patients is decreased. METHODS: In this retrospective cross-sectional study, we compared 143 CNO patients and 58 healthy volunteers, between 18 to 80 years old. We assessed nasal patency by means of rhinomanometry (RM) and measured susceptibility of intranasal trigeminal system by the trigeminal lateralization task (TLT). RESULTS: TLT scores were significantly lower in CNO patients compared to controls (p less than 0.001), but RM scores were not different between groups. Accordingly, TLT allowed to identify CNO patients with an accuracy of the area under the curve (AUC) of 0.78, while the value for RM was at chance (AUC=0.47). CNO patients showed normal reaction to vasoconstrictive agents with significantly lower RM values after Xylomethazoline application. CONCLUSION: Results suggest that reported nasal obstruction in CNO patients without any obvious anatomical obstacle and resistant to medical treatment may be linked to decreased perception of nasal airflow rather than physical obstruction. In this sub-set of CNO patients, trigeminal testing more adequately reflects the reported obstruction than nasal resistance assessment does. In future studies, the relation of the trigeminal status and the subjective sensation of nasal obstruction needs to be addressed with validated patient rated outcome measures (PROMs).