Persistent chemosensory dysfunction in a young patient with mild COVID-19 with partial recovery 15 months after the onset

Abstract

Objective It is reported that recovery from COVID-19 chemosensory deficit generally occurs in a few weeks, although olfactory dysfunction may persist longer. Here, we provide a detailed follow-up clinical investigation in a very young female patient (17-year-old) with a long-lasting anosmia after a mild infection, with partial recovery 15 months after the onset. Methods Neuroimaging and neurophysiologic assessments as well as olfactory mucosa swabbing for microbiological and immunocytochemical analyses were performed. Olfactory and gustatory evaluations were conducted through validated tests. Results Chemosensory evaluations were consistent with anosmia associated with parosmia phenomena and gustatory impairment, the latter less persistent. Brain MRI (3.0 T) showed no microvascular injury in olfactory bulbs and brain albeit we cannot rule out slight structural abnormalities during the acute phase, and a high-density EEG was negative. Immunocytochemistry of olfactory mucosa swabs showed high expression of ACE2 in sustentacular cells and lower dot-like cytoplasmic positivity in neuronal-shaped cells. Discussion The occurrence of long-term persistent olfactory deficit in spite of the absence of structural brain and olfactory bulb involvement supports the view of a possible persistent dysfunction of both sustentacular cells and olfactory neurons. The gustatory dysfunction even if less persisting for the described features could be related to a primary gustatory system involvement. Future longitudinal studies are needed to investigate the persistence of chemosensory impairment, which could have a relevant impact on the daily life. Supplementary Information The online version contains supplementary material available at 10.1007/s10072-021-05635-y.

Visualizing in deceased COVID-19 patients how SARS-CoV-2 attacks the respiratory and olfactory mucosae but spares the olfactory bulb

“…The sequence of pathobiological events leading to olfactory dysfunction may include an inflammatory component (Kirschenbaum et al, 2020). Irreparable tissue damage at the level of the OM (Fodoulian et al, 2020;Vaira et al, 2020a) may underlie the persistent anosmia observed in a subset of COVID-19 patients (Cecchini et al, 2021;Renaud et al, 2021).…”

Brain Imaging Changes in Patients Recovered From COVID-19: A Narrative Review

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Fatigue and perceived fatigability, not objective fatigability, are prevalent in people with post-COVID-19

“…Similarly, recent studies in people with post-COVID-19 symptoms found no significant differences in MRI findings between subjects with and without cognitive impairments and fatigue after acute infection (Hellgren et al 2021 ; Huang et al 2022 ). Moreover, despite several studies detecting changes in brain microstructure of people with post-COVID-19 with structural MRI (Colonna et al 2020 ; Freeman et al 2021 ; Hixon et al 2021 ; Nuzzo et al 2021 ; Cecchini et al 2022 ) and DTI (Liu et al 2019 ; Tian et al 2020 ; Qin et al 2021 ), no correlations with fatigue symptoms have been reported. Other recent studies found that post-COVID-19 symptoms were rarely associated with damage of the central or peripheral nervous system (Fleischer et al 2022 ) or alterations in regional cerebral glucose metabolism (Dressing et al 2022 ).…”