Overview
The present study aims to describe the structural tissue and cell characteristics of the olfactory mucosa in patients with persistent anosmia (≥2 years) due to COVID-19 or head-trauma, in comparison to healthy individuals with intact olfactory function. In order to avoid possible age-related degenerative changes in the neuro-epithelium, both patients and controls are between 25 and 35 years of age.
Eligibility
Inclusion Criteria:
- Legally competent to vouch for their own study participation.
- Informed and written consent for participation in this study.
- Study group 1 (Post-COVID anosmia)
- Diagnosed with persistent anosmia for approximately two years concurring with positive SARS-CoV-2 PCR-test between 2019 and 2020.
- Sniffin'sticks test with a threshold-discrimination-identification-score(TDI)≤16
- Between 25 and 35 years of age.
Study group 2 (Post-trauma anosmia)
- Diagnosed with persistent anosmia for approximately two years concurring with head trauma.
- Sniffin'sticks test with a threshold-discrimination-identification-score(TDI)≤16
- Between 25 and 35 years of age.
Study group 3 (Controls):
- Between 25 and 35 years of age.
- Undergoing reposition of a nasal fracture in general anaesthesia
Exclusion Criteria:
- <25 years of age.
- >35 years of age.
- Chronic rhinosinusitis with/without polyps.
- Nasal cancer.
- Presence of viral or bacterial rhinosinusitis.
- Uncontrolled allergic rhinosinusitis.
- Coagulation deficiencies, e.g. haemophilia.
- Use of anticoagulants.
- Not able to undergo general anaesthesia.
- Pregnancy.
- Any use of nasal detumescence drugs ≤2 weeks before biopsy.
- Any use of nasal steroids ≤3 months before biopsy.
- Use of nasal inhaled recreational drugs ≤3 month before biopsy.
- Participants not able to communicate in Danish or English.
- Major Depression Inventory (MDI) score ≥27 [49, 50]
- Mini Mental State Examination (MMSE) score ≤ 26 [51]
- Study group 1 (Post-COVID anosmia)
- Anosmia for less than two years or more than two and a half years.
- No positive SARS-CoV-2 PCR-test concurring with olfactory dysfunction.
- History of olfactory dysfunction before COVID-19 infection.
- Study group 2 (Post-trauma anosmia)
- Anosmia for less than two years or more than approximately two-three years.
- Anosmia without concurring with head trauma
- History of prior olfactory dysfunction before head trauma.
- Study group 3 (Controls) 1. Known olfactory dysfunction.