Department of Neurology and Stroke Unit and Laboratory of Neuroscience, Istituto Auxologico Italiano IRCCS, Milan, Italy.
Department of Pathophysiology and Transplantation, Dino Ferrari Center, Università degli Studi di Milano, Milan, Italy.
Neurol Sci. 2021 Jun;42(6):2183-2189. doi: 10.1007/s10072-021-05200-7. Epub 2021 Mar 26.
Olfactory dysfunction in coronavirus disease 2019 (COVID-19) is common during acute illness and appears to last longer than other symptoms. The aim of this study was to objectively investigate olfactory dysfunction in two cohorts of patients at two different stages: during acute illness and after a median recovery of 4 months.
Twenty-five acutely ill patients and 26 recovered subjects were investigated. Acute patients had a molecular diagnosis of COVID-19; recovered subjects had a positive antibody assay and a negative molecular test. A 33-item psychophysical olfactory identification test tailored for the Italian population was performed.
Median time from symptoms onset to olfactory test was 33 days in acute patients and 122 days in recovered subjects. The former scored a significantly higher number of errors at psychophysical testing (median [IQR]: 8 [13] vs 3 [2], p < 0.001) and were more frequently hyposmic (64% vs 19%, p = 0.002). Recovered subjects reported a variable time to subjective olfactory recovery, from days up to 4 months. Participants included in the study reported no significant nasal symptoms at olfactory testing. Among recovered subject who reported olfactory loss during acute COVID-19, four (27%) were still hyposmic. Demographic and clinical characteristics did not show significant associations with olfactory dysfunction.
Moderate-to-severe hospitalized patients showed a high level and frequency of olfactory dysfunction compared to recovered subjects. In the latter group, subjects who reported persisting olfactory dysfunction showed abnormal scores on psychophysical testing, indicating that, at least in some subjects, persistent hyposmia may represent a long-term sequela of COVID-19.
在 2019 年冠状病毒病（COVID-19）急性发病期间，嗅觉功能障碍很常见，且似乎比其他症状持续时间更长。本研究旨在客观地研究两个队列的患者在两个不同阶段的嗅觉功能障碍：急性发病期间和中位数恢复 4 个月后。
共调查了 25 例急性发病患者和 26 例恢复期患者。急性患者的 COVID-19 经分子诊断确诊；恢复期患者的抗体检测呈阳性，分子检测呈阴性。对患者进行了一项针对意大利人群的 33 项嗅觉识别心理物理学测试。
急性患者症状发作至嗅觉测试的中位时间为 33 天，恢复期患者为 122 天。前者在心理物理学测试中错误得分显著更高（中位数[四分位数间距]：8 [13] 比 3 [2]，p < 0.001），且嗅觉减退的发生率更高（64%比 19%，p = 0.002）。恢复期患者报告主观嗅觉恢复的时间不同，从数天到 4 个月不等。接受嗅觉测试的患者报告在嗅觉测试时无明显鼻部症状。在报告急性 COVID-19 期间嗅觉丧失的恢复期患者中，有 4 人（27%）仍嗅觉减退。人口统计学和临床特征与嗅觉功能障碍无显著相关性。
与恢复期患者相比，中重度住院患者表现出更高水平和更高频率的嗅觉功能障碍。在后者中，报告持续嗅觉功能障碍的患者在心理物理学测试中得分异常，这表明，至少在一些患者中，持续嗅觉减退可能是 COVID-19 的长期后遗症。
