From the Guidelines
COVID-19 can cause autonomic nervous system abnormalities that may lead to fainting episodes, and patients experiencing post-COVID fainting should be managed with a combination of lifestyle modifications and possibly medications to improve symptoms and quality of life. These abnormalities often manifest as postural orthostatic tachycardia syndrome (POTS) or dysautonomia, where the body struggles to regulate heart rate, blood pressure, and other automatic functions when changing positions 1. The pathogenesis of long COVID, which includes dysautonomia, is thought to involve multiple factors, including persisting reservoirs of SARS-CoV-2 in tissues, immune dysregulation, and autoimmunity 1.
For patients experiencing post-COVID fainting, I recommend the following:
- Increased fluid intake (2-3 liters daily) and salt consumption (8-10g daily) to help regulate blood volume and pressure
- Compression garments for the lower body to improve blood flow and reduce symptoms of POTS
- A gradual exercise program focusing on recumbent exercises initially to help improve cardiovascular function and reduce deconditioning
- Medications such as fludrocortisone (starting at 0.1mg daily) to increase blood volume, midodrine (2.5-10mg three times daily) to raise blood pressure, or beta-blockers like propranolol (10-20mg twice daily) to manage heart rate 1
It is essential to note that these symptoms typically improve over 6-12 months, but some patients require longer treatment 1. Patients should rise slowly from lying or sitting positions, avoid prolonged standing, and stay well-hydrated, especially in hot weather or before exercise. A 10-minute active stand test can be used to assess for dynamic changes in blood pressure and heart rate, and ambulatory rhythm monitoring can help exclude arrhythmia and define the pattern of heart rate elevation 1.
The mechanism of autonomic nervous system abnormalities in post-COVID patients involves viral damage to autonomic nerve fibers and receptors, immune-mediated inflammation affecting autonomic ganglia, and deconditioning from prolonged illness 1. By addressing these underlying mechanisms and providing appropriate management, we can improve symptoms, reduce morbidity and mortality, and enhance quality of life for patients experiencing post-COVID fainting.
From the Research
Autonomic Nervous System Abnormalities Post COVID-19
- Autonomic nervous system (ANS) abnormalities have been reported in patients post COVID-19, including postural orthostatic tachycardia syndrome (POTS), orthostatic hypotension, and neurocardiogenic syncope 2, 3, 4.
- Studies have shown that these abnormalities can persist for several months after COVID-19 infection, with 85% of patients experiencing residual autonomic symptoms 6-8 months after infection 2.
- The Composite Autonomic Symptom Scale 31 (COMPASS-31) questionnaire has been used to assess dysautonomic symptoms in post-COVID patients, with the most affected domains being orthostatic intolerance, sudomotor, gastrointestinal, and pupillomotor dysfunction 3.
Fainting and Autonomic Dysfunction
- Fainting, also known as syncope, has been reported in patients with autonomic dysfunction post COVID-19, including those with POTS and orthostatic hypotension 2, 4.
- Autonomic testing has shown abnormalities in sudomotor, cardiovagal, and cardiovascular adrenergic function in patients with post-COVID autonomic dysfunction 4.
- The temporal association between COVID-19 infection and autonomic symptoms implies a causal relationship, although this cannot be proven by current studies 4, 5, 6.
Management and Implications
- Management of autonomic dysfunction post COVID-19 includes non-pharmacologic and pharmacologic therapies, as well as supportive care to alleviate symptoms 2, 5.
- Recognition of autonomic dysfunction as a potential complication of COVID-19 is essential for providing appropriate care and management to affected patients 3, 5, 6.
- Further research is needed to understand the pathobiology of autonomic dysfunction post COVID-19 and to develop effective management strategies 5, 6.