Department of Otorhinolaryngology, Mansoura University, Mansoura, Egypt.
Radio-diagnosis and Interventional Radiology, Faculty of medicine, Mansoura University, Mansoura, Egypt.
Am J Rhinol Allergy. 2023 Jul;37(4):456-463. doi: 10.1177/19458924231163969. Epub 2023 Mar 21.
Olfactory dysfunction has been reported in 47.85% of COVID patients. It can be broadly categorized into conductive or sensorineural olfactory loss. Conductive loss occurs due to impaired nasal air flow, while sensorineural loss implies dysfunction of the olfactory epithelium or central olfactory pathways.
The aim of this study was to analyze the clinical and imaging findings in patients with COVID-related olfactory dysfunction. Additionally, the study aimed to investigate the possible mechanisms of COVID-related olfactory dysfunction.
The study included 110 patients with post-COVID-19 olfactory dysfunction, and a control group of 50 COVID-negative subjects with normal olfactory function. Endoscopic nasal examination was performed for all participants with special focus on the olfactory cleft. Smell testing was performed for all participants by using a smell diskettes test. Olfactory pathway magnetic resonance imaging (MRI) was done to assess the condition of the olfactory cleft and the dimensions and volume of the olfactory bulb.
Olfactory dysfunction was not associated with nasal symptoms in 51.8% of patients. MRI showed significantly increased olfactory bulb dimensions and volume competed to controls. Additionally, it revealed olfactory cleft edema in 57.3% of patients. On the other hand, radiological evidence of sinusitis was detected in only 15.5% of patients.
The average olfactory bulb volumes were significantly higher in the patients' group compared to the control group, indicating significant edema and swelling in the olfactory bulb in patients with COVID-related olfactory dysfunction. Furthermore, in most patients, no sinonasal symptoms such as nasal congestion or rhinorrhea were reported, and similarly, no radiological evidence of sinusitis was detected. Consequently, the most probable mechanism of COVID-related olfactory dysfunction is sensorineural loss through virus spread and damage to the olfactory epithelium and pathways.
有报道称,47.85%的 COVID 患者存在嗅觉功能障碍。它可以大致分为传导性或感觉神经性嗅觉丧失。传导性损失是由于鼻气流受损引起的,而感觉神经性损失则意味着嗅觉上皮或中央嗅觉通路的功能障碍。
本研究旨在分析 COVID 相关嗅觉功能障碍患者的临床和影像学表现。此外,本研究旨在探讨 COVID 相关嗅觉功能障碍的可能机制。
本研究纳入了 110 例 COVID 后嗅觉功能障碍患者和 50 例 COVID 阴性嗅觉功能正常的对照组。所有参与者均进行了鼻内窥镜检查,特别关注嗅裂。所有参与者均进行了嗅觉圆盘测试进行嗅觉测试。进行嗅觉通路磁共振成像(MRI)检查,以评估嗅裂的情况以及嗅球的尺寸和体积。
嗅觉功能障碍与 51.8%患者的鼻部症状无关。MRI 显示,与对照组相比,嗅球的尺寸和体积明显增大。此外,在 57.3%的患者中发现嗅裂水肿。另一方面,仅在 15.5%的患者中发现窦炎的放射学证据。
与对照组相比,患者组的平均嗅球体积明显更高,表明 COVID 相关嗅觉功能障碍患者的嗅球存在明显的水肿和肿胀。此外,大多数患者没有鼻塞或流涕等鼻内症状,同样也没有发现窦炎的放射学证据。因此,COVID 相关嗅觉功能障碍最可能的机制是病毒传播和嗅上皮及通路损伤导致的感觉神经性丧失。