Intranasal trigeminal function in chronic rhinosinusitis: a review

ABSTRACT

Introduction

Chronic rhinosinusitis (CRS) affects 5–12% of the general population with significant effects on quality of life. Chronic inflammation also seems to affect intranasal trigeminal sensitivity.

Areas covered

A systematic literature search was done in Scopus, Web of Science, and PubMed in February 2023. The review addressed intranasal trigeminal function in patients with CRS and summarized current knowledge on trigeminal function as it relates to the symptoms, assessment, and treatment of CRS.

Expert opinion

Olfaction and trigeminal function are synergistic and this interaction may contribute to trigeminal dysfunction in CRS. Aside from anatomic blockage through polypoid mucosal changes, trigeminal dysfunction may affect the perception of nasal obstruction in CRS. Upregulated immune defense mechanisms leading to damage of nerve endings, changes in nerve growth factor release or other mechanisms may be responsible for trigeminal dysfunction in CRS. Since the pathophysiology of trigeminal dysfunction in CRS is poorly understood, current treatment recommendations are directed toward the therapy of CRS as an underlying cause, although the effect of surgery and corticosteroids on trigeminal function remains unclear. A standardized and validated trigeminal test that is accessible and easy to use in clinical settings would be beneficial for future studies.

KEYWORDS:

• chemesthesis
• chronic rhinosinusitis
• nasal polyps
• nose
• olfaction
• trigeminal
• chemosensory

Article highlights

• Decreased trigeminal function has been documented in chronic rhinosinusitis (CRS) but results of studies depended on the stimulus, method of testing, and other factors.

• Trigeminal event-related potentials and trigeminal lateralization tests were the most commonly used tests to assess trigeminal function.

• The lack of standardized and validated measures for trigeminal function makes comparing results of different studies difficult.

• Subsequent studies would benefit from having control groups, larger sample sizes, and standardized and validated methods of trigeminal function measurement.

• Olfaction and trigeminal functions are synergistic, with both olfactory and trigeminal functions related to odor perception. Trigeminal dysfunction in CRS may likewise have contributions from this olfactory–trigeminal interaction.

• Aside from anatomic blockage through polypoid changes of the mucosa, trigeminal dysfunction may affect the perception of nasal obstruction in CRS.

• Several mechanisms may be responsible for trigeminal dysfunction in CRS including inflammatory responses related to upregulated defense mechanisms leading to damage of trigeminal nerve endings, or changes in nerve growth factor release. Discovery of exact mechanisms may have profound implications for diagnosis and management, as it may be more geared toward the different types of inflammation (Types I, II, or III) observed in CRS.

• We hypothesize a framework for trigeminal dysfunction in CRS, but further studies are required to determine the exact mechanisms of trigeminal function changes in CRS, and the influence of various treatment modalities, including biologicals, on intranasal trigeminal function.

Declaration of interest

During the last 3 years, T Hummel did research together with and/or received funds from Sony, Stuttgart, Germany; Smell and Taste Lab, Geneva, Switzerland; Takasago, Paris, France; aspuraclip, Schönefeld, Germany; Baia Foods, Madrid, Spain. The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript.

Reviewer disclosures

Peer reviewers on this manuscript have no relevant financial or other relationships to disclose.

Supplementary material

Supplemental data for this article can be accessed online at https://doi.org/10.1080/1744666X.2023.2231149

Additional information

Funding

This paper was funded by TH & AKH: Deutsche Forschungsgemeinschaft (DFG HU 441/21-1; project number 468981129; TH: Volkswagenstiftung (project PERCEPTRONICS Az 9B396).