Functional and Morphological Disorders of Taste and Olfaction in
COVID-19-Patients
Abstract
Objectives: To test the prevalence and evolution of acute olfactory and
gustatory functional impairment and of their morphologic correlates in
COVID-19 patients who require hospitalization due to COVID-19-related
respiratory conditions. Key-words: COVID-19, taste, olfaction,
electrogustometry, contact endoscopy Design: Electrogustometric (EGM) -
thresholds at the tongue area supplied by the chorda tympani, at the
soft palate and at the vallate papillae area were recorded bilaterally.
Olfaction was examined by Sniffin’ sticks. The patients’ nasal and oral
mucosa (fungiform papillae, fpap) were examined by contact endoscopy.
Setting: Tertiary referral medical centre. Patients: 53 consecutive
hospitalized patients (23 males, 30 females, age 42,54 ± 10, 95 yrs)
with RT-PCR-confirmed COVID-19 diagnosis were included. Patients have
been examined twice: just after hospital discharge and 4-6 weeks later.
Main outcome measures: EGM-thresholds and taste strips,
Schniffin-Sticks, Contact-Endoscopyesults: EGM-thresholds in patients
were significantly higher at both instances than those of healthy
subjects. EGM-thresholds at the second measurement were significantly
lower than those at the first measurement. Accordingly, patient-reported
gustatory outcomes were improved at the second measurement. The same
pattern has been found using Sniffin’ sticks. Significant alterations in
form and vascularization of fPap have been detected in patients,
especially at the first instance. Conclusions: COVID-19 affects both
gustatory and olfactory functions. It also affects in parallel the
structure and vascularization of both nasal and oral mucosa, although
the nasal mucosa to a much less, non-significant, extent. Our findings
suggest that COVID-19 may cause a mild to profound neuropathy of
multiple cranial nerves.