What is ‘Long Covid,’ ‘post-COVID-19 syndrome,’ or ‘long-haul COVID’?
According to Saurabh Mehandru & Miriam Merad’s article1 published in Nature on February 1st, 2022, the Centers for Disease Control and Prevention use the term ‘post-COVID conditions’ as an umbrella term for “the wide range of health consequences that are present ≥4 (four) weeks after infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2).” Mehandru and Merad published their review to try to understand why Covid-19 affects individuals for the long term with a variety of symptoms that can include fatigue, lack of motivation, shortness of breath, racing heart, abnormal sense of smell or absence of smell, issues with memory and concentration, and a variety of other symptoms.
What causes ‘Long Covid’?
The National Institutes of Health are still trying to understand why some people get ‘Long Covid’ and others don’t, and data is still being collected. Infectious disease researchers report that some underlying pathological causes may be related to chronic inflammation, autoimmune response and lingering viral presence. Researchers in Spain have suggested that an autonomic nervous system (ANS) imbalance, with decreased parasympathetic activity, may explain some of the Long Covid symptoms like heart rate variability.2 In 2008, Dantzer published an article about “sickness behavior,” suggesting that symptoms like fatigue, orthostatic intolerance, brain fog, anosmia, and ageusia/dysgeusia are reflective of the autonomic nervous system response to pro-inflammatory cytokines.3 Scientists in Switzerland and Germany published an article in January 20224 stating: “based on our knowledge of the modulation of inflammation by the ANS, we propose that a reflectory malfunction of the ANS with hyperactivity of the sympathetic nervous system (SNS) may be involved in the generation of acute hyperinflammation.” They believe that “sympathetic hyperactivity” triggers a “hyperresponsiveness of the immune system (cytokine storm),” leading to subsequent tissue damage. Covid-19 is a virus that could trigger this reflectory, neuroimmunological and inflammatory cascade within the ANS.
What is currently being done for Long Covid?
According to the British Health Heart Foundation5, there isn’t one single treatment or medication to treat Long Covid. They advise that since everyone’s experience is different, each patient should speak to a medical provider about their symptoms and be advised about how to best manage them and what other support is available. British general practitioners may refer their patients to a specialist rehabilitation service, or to a specialist, like a cardiologist or a gastroenterologist, who may look into the specific organ dysfunction that their patients are experiencing.
Scientists in Switzerland and Germany have suggested focusing on regulating the hyperinflammatory response through resetting the autonomic nervous system (ANS). Within the overreaction of the ANS, several interdependent pathological positive feedback loops can be detected, in which the sympathetic nervous system plays an important role. They have been researching the potential of regulating hyperinflammation by influencing the SNS. They believe that a stellate ganglion block (SGB) with local anesthetics may temporarily disrupt the pathological positive feedback loops and allow the neuroimmune system the opportunity to reorganize itself.
In Alaska, a doctor recently published a case report of successfully relieving symptoms of two Long Covid patients through a treatment called a stellate ganglion block with a vagus nerve block6. His patient’s response to the treatment suggests that dysautonomia could be at play in the pathophysiology of Long Covid. Further research is needed in larger sample sizes to determine if this is a significant and reliable treatment for Long Covid, and to determine additional treatments for Long Covid.
As our global society approaches the next phase of Covid, it is encouraging to see medical providers and researchers worldwide looking for treatments to address the Long Covid symptoms that affect many.
Citations:
Mehandru, S., Merad, M. Pathological sequelae of long-haul COVID. Nat Immunol 23, 194–202 (2022). https://doi.org/10.1038/s41590-021-01104-y
Long Covid: the Symptoms and Tips for Recovery. British Heart Foundation. Charity No. 225971. Registered in England & Wales as No. 699547 at Greater London House, 180 Hampstead Road, London NW1 7AW. Registered as Charity in Scotland No. SC039426. Referenced Mar 10, 2022. https://www.bhf.org.uk/informationsupport/heart-matters-magazine/news/coronavirus-and-your-health/long-covid
Liu LD, Duricka DL. Stellate ganglion block reduces symptoms of Long Covid: A case series. J Neuroimmunol. 2022 Jan 15;362:577784. doi: 10.1016/j.jneuroim.2021.577784. Epub 2021 Dec 8. PMID: 34922127; PMCID: PMC8653406.
Dantzer R., O’Connor J.C., Freund G.G., Johnson R.W., Kelley K.W. From inflammation to sickness and depression: when the immune system subjugates the brain. Nat. Rev. Neurosci. 2008 Jan;9(1):46–56. doi: 10.1038/nrn2297. PMID: 18073775; PMCID: PMC2919277.
Scientists propose cause of symptoms, treatment for Long Covid-19. 2022 Feb 14; University of Minnesota Center for Infectious Disease Research and Policy https://www.cidrap.umn.edu/news-perspective/2022/02/scientists-propose-cause-symptoms-treatment-long-covid-19
Fischer L, Barop H, Ludin SM, Schaible HG. Regulation of acute reflectory hyperinflammation in viral and other diseases by means of stellate ganglion block. A conceptual view with a focus on Covid-19. Auton Neurosci. 2022 Jan;237:102903. doi: 10.1016/j.autneu.2021.102903. Epub 2021 Nov 10. PMID: 34894589.
References:
1 Mehandru, S., Merad, M. Pathological sequelae of long-haul COVID. Nat Immunol 23, 194–202 (2022). https://doi.org/10.1038/s41590-021-01104-y
2 Scientists propose cause of symptoms, treatment for Long Covid-19. 2022 Feb 14; University of Minnesota Center for Infectious Disease Research and Policy https://www.cidrap.umn.edu/news-perspective/2022/02/scientists-propose-cause-symptoms-treatment-long-covid-19
3 Dantzer R., O’Connor J.C., Freund G.G., Johnson R.W., Kelley K.W. From inflammation to sickness and depression: when the immune system subjugates the brain. Nat. Rev. Neurosci. 2008 Jan;9(1):46–56. doi: 10.1038/nrn2297. PMID: 18073775; PMCID: PMC2919277.
4 Liu LD, Duricka DL. Stellate ganglion block reduces symptoms of Long Covid: A case series. J Neuroimmunol. 2022 Jan 15;362:577784. doi: 10.1016/j.jneuroim.2021.577784. Epub 2021 Dec 8. PMID: 34922127; PMCID: PMC8653406.
5 Fischer L, Barop H, Ludin SM, Schaible HG. Regulation of acute reflectory hyperinflammation in viral and other diseases by means of stellate ganglion block. A conceptual view with a focus on Covid-19. Auton Neurosci. 2022 Jan;237:102903. doi: 10.1016/j.autneu.2021.102903. Epub 2021 Nov 10. PMID: 34894589.
6 Long Covid: the Symptoms and Tips for Recovery. British Heart Foundation. Charity No. 225971. Registered in England & Wales as No. 699547 at Greater London House, 180 Hampstead Road, London NW1 7AW. Registered as Charity in Scotland No. SC039426. Referenced Mar 10, 2022. https://www.bhf.org.uk/informationsupport/heart-matters-magazine/news/coronavirus-and-your-health/long-covid
