Vagus Nerve Dysfunction in the Post-COVID-19 Condition: a pilot cross sectional study.

Methods: We performed a cross-sectional pilot study in subjects with PCC with symptoms suggesting vagus nerve dysfunction (n=30) and compared to subjects fully recovered from acute COVID-19 (n=14) and individuals never infected (n=16). We evaluated the structure and function of the vagus nerve and evaluated the structure and function of respiratory muscles.

Results: Participants were mostly women (24/30, 80%), the median age was n 44 years [interquartile range (IQR) 35-51 years]. Their most prevalent symptoms were cognitive dysfunction 25/30 (83%), dyspnea 24/30 (80%) and tachycardia 24/30 (80%). Compared with COVID-19-recovered and uninfected controls, respectively, subjects with PCC were more likely to show thickening and hyperechogenic vagus nerve in neck ultrasounds (cross-sectional area (CSA) (mean ± SD): 2.4 ± 0.97mm2 vs. 2 ± 0.52mm2 vs. 1.9 ± 0.73 mm2, p=0.08), reduced esophageal-gastric-intestinal peristalsis (34% vs 0% vs 21%, p=0.02), gastroesophageal reflux (34% vs 19% vs 7%, p=0.13), and hiatal hernia (25% vs 0% vs 7%, p=0.05). Subjects with PCC showed flattening hemidiaphragms (47% vs 6% vs 14%, p=0.007), and reductions in maximum inspiratory pressure (62% vs. 6% vs. 17%, p ≤0.001), indicating respiratory muscle weakness. The latter findings suggest additional involvement of the phrenic nerve.

Conclusion: Participants were mostly women (24/30, 80%), the median age was n 44 years [interquartile range (IQR) 35-51 years]. Their most prevalent symptoms were cognitive dysfunction 25/30 (83%), dyspnea 24/30 (80%) and tachycardia 24/30 (80%). Compared with COVID-19-recovered and uninfected controls, respectively, subjects with PCC were more likely to show thickening and hyperechogenic vagus nerve in neck ultrasounds (cross-sectional area (CSA) (mean ± SD): 2.4 ± 0.97mm2 vs. 2 ± 0.52mm2 vs. 1.9 ± 0.73 mm2, p=0.08), reduced esophageal-gastric-intestinal peristalsis (34% vs 0% vs 21%, p=0.02), gastroesophageal reflux (34% vs 19% vs 7%, p=0.13), and hiatal hernia (25% vs 0% vs 7%, p=0.05). Subjects with PCC showed flattening hemidiaphragms (47% vs 6% vs 14%, p=0.007), and reductions in maximum inspiratory pressure (62% vs. 6% vs. 17%, p ≤0.001), indicating respiratory muscle weakness. The latter findings suggest additional involvement of the phrenic nerve.