Parasympathetic autonomic dysfunction is more often evidenced than sympathetic autonomic dysfunction in fluctuating and polymorphic symptoms of "long-COVID" patients

Abstract

Several disabling symptoms potentially related to dysautonomia have been reported in “long-COVID” patients. Unfortunately, these symptoms are often nonspecific, and autonomic nervous system explorations are rarely performed in these patients. This study aimed to evaluate prospectively a cohort of long-COVID patients presenting severe disabling and non-relapsing symptoms of potential dysautonomia and to identify sensitive tests. Autonomic function was assessed by clinical examination, the Schirmer test; sudomotor evaluation, orthostatic blood pressure (BP) variation, 24-h ambulatory BP monitoring for sympathetic evaluation, and heart rate variation during orthostatism, deep breathing and Valsalva maneuvers for parasympathetic evaluation. Test results were considered abnormal if they reached the lower thresholds defined in publications and in our department. We also compared mean values for autonomic function tests between patients and age-matched controls. Sixteen patients (median age 37 years [31–43 years], 15 women) were included in this study and referred 14.5 months (median) [12.0–16.5 months] after initial infection. Nine had at least one positive SARS-CoV-2 RT-PCR or serology result. Symptoms after SARS-CoV-2 infection were severe, fluctuating and disabling with effort intolerance. Six patients (37.5%) had one or several abnormal test results, affecting the parasympathetic cardiac function in five of them (31%). Mean Valsalva score was significantly lower in patients than in controls. In this cohort of severely disabled long-COVID patients, 37.5% of them had at least one abnormal test result showing a possible contribution of dysautonomia to these nonspecific symptoms. Interestingly, mean values of the Valsalva test were significantly lower in patients than in control subjects, suggesting that normal values thresholds might not be appropriate in this population.

Functional Limitations and Exercise Intolerance in Patients With Post-COVID Condition

“…While deconditioning can partially explain the observed orthostatic intolerance (blood volume reduction can lead to a heart rate elevation), we cannot exclude the possibility that impaired autonomic function after viral infection (ie, higher levels of autoantibodies against α and β adrenoreceptors and muscarinic receptors) led to the exaggerated heart rate response. Patients with PCC also showed lower heart rate variability during deep breathing and increased foot latency as assessed in the sympathetic skin response test, suggesting parasympathetic nervous system involvement in a subgroup of patients with PCC . Finally, patients with PCC showed higher pulse wave velocity, indicating increased arterial stiffness compared with controls.…”

Association of vascular netosis with COVID-19 severity in asymptomatic and symptomatic patients

“… 27 This postulate should be placed in the context of previous reports associating mitochondria dysfunction with COVID-19. 54 , 55 , 56 Further support for such a perspective is offered by the very recent study by Guarnieri et al., 57 which describes the genetic mechanisms that damage mitochondria in organs and which, in doing so, may contribute to COVID-19 and perhaps to long COVID. It has been suggested that ROS overproduction is involved in the pathophysiological mechanisms of both pathologies, 57 and that in a similar manner, the formation of NETs is promoted by the mitochondrial ROS in neutrophils in patients with various NETopathies.…”

Autonomic cardiac function in children and adolescents with long COVID: a case-controlled study

“…Our data show that, on the whole, children with long COVID present a parasympathetic overtone, which might contribute to the symptoms of patients by several ways [ 35 ], including changes in the blood flow resulting in abnormal muscle, lung, and brain perfusion [ 22 – 26 ], leading to some of the most common and impactful long COVID symptoms, like fatigue, muscle pain, exercise intolerance, and dyspnea as well as cognitive symptoms like brain fog.…”