If you have FND but identical symptoms to Long COVID, is causation the diagnosis?
I’ve seen this question a lot, and it’s one I’ve asked myself—does the cause of an illness determine the diagnosis? The way medical diagnoses are handed out, causation often dictates what label you get. If you had COVID-19 and then developed autonomic dysfunction, PEM (post-exertional malaise), internal tremors, cognitive issues, to name but a few, you’d likely be diagnosed with Long COVID. But if you have the exact same symptoms without a known viral trigger, you might end up with an FND (Functional Neurological Disorder) diagnosis instead. But does that really make them different illnesses?
But most people with Long COVID, like with fibromyalgia and ME/CFS, have no biological markers.
Exactly! And this is where things get even messier. Despite ongoing research into immune dysfunction, micro clots, and autonomic dysregulation in Long COVID, the majority of patients with these conditions don’t have clear, universally accepted biological markers on standard tests. That’s why so many of these illnesses are diagnosed based on symptoms rather than objective lab findings.
So if two people have identical symptoms—dysautonomia, PEM, internal tremors, cognitive dysfunction—but one had COVID and the other didn’t, are they experiencing different illnesses?
That’s the million-dollar question. If we focus on symptoms alone, it suggests they’re dealing with the same underlying dysfunction, just triggered by different events. One person’s autonomic nervous system may have been thrown off balance by COVID, while another’s was triggered by a concussion, a different virus, or prolonged stress.
It’s possible that FND, ME/CFS, fibromyalgia, and Long COVID are all variations of the same nervous system dysfunction, just with different starting points. This could explain why so many treatments overlap—pacing, brain retraining, autonomic regulation, anti-inflammatory diets, and so on.
So does causation really matter, then?
In some ways, yes. The medical system loves categorizing conditions based on cause. If you had COVID first, you’re put in one box. If your symptoms developed after trauma or stress, you’re put in another. But in terms of actually treating the symptoms and improving quality of life, does it matter how you got there? Or does it matter more that we understand the mechanisms behind these conditions?
After all, if you break your leg falling off your bike or playing football, it’s still a broken leg—the treatment is the same.
Could this lead to misdiagnosis?
Absolutely. Someone with post-viral dysautonomia but no positive test for COVID might get labelled with FND, while someone with the same symptoms and a confirmed COVID infection gets a Long COVID diagnosis. This distinction can impact treatment options, research funding, and even how seriously they’re taken by doctors.
Does this division cause problems in patient communities?
100%. People with ME/CFS, fibromyalgia, FND, and Long COVID often experience the same struggles—nervous system dysfunction, PEM, autonomic issues—yet they’re given different labels based on what triggered their illness rather than what they’re actually experiencing. And that can create unnecessary division.
Long COVID has gained more recognition because of its connection to COVID-19, while ME/CFS and FND patients have been fighting for validation for decades. Some Long COVID patients reject comparisons to ME/CFS or FND because they fear being dismissed as having a “functional” or psychosomatic disorder. Meanwhile, some ME/CFS and fibromyalgia patients feel frustrated that they’ve been ignored for years, only for Long COVID to suddenly get attention for the same symptoms.
And what about FND? It gets dismissed even more, doesn’t it?
Unfortunately, yes. FND patients often get told their symptoms are “functional” in a way that implies psychological rather than neurological dysfunction. But if someone with identical symptoms has a Long COVID diagnosis, they’re often taken more seriously because of the post-viral aspect. That can be incredibly invalidating for FND patients, even when their symptoms are identical.
So do the same treatments help across these conditions?
More often than not, yes. If the underlying dysfunction is similar, then it makes sense that the same recovery strategies would be useful. Many people who have recovered from these conditions have done so through a combination of dietary changes, nervous system regulation, and mind-body practices. Pacing, improving gut health, reducing inflammation, breathwork, meditation, and gradually increasing activity all seem to be common factors in recovery stories across Long COVID, ME/CFS, fibromyalgia, and FND.
This also suggests that instead of treating these conditions as separate entities, medical research should focus on what helps the nervous system recover and function properly, regardless of the original trigger. Whether the dysfunction started with a virus, trauma, or another stressor, the path to healing may be more universal than we think.
What’s the takeaway?
Instead of dividing people into categories based on what triggered their illness, we should be looking at the common underlying mechanisms—nervous system dysfunction, immune dysregulation, metabolic shifts—and finding effective treatments that help everyone with these conditions. The label might differ, but the struggle is often the same. It’s time to focus on solutions rather than divisions.
References
ME/CFS and Long COVID share similar symptoms and biological ...
The similar symptoms and pathology of ME/CFS and Long COVID raise the question of whether these disorders represent just two examples of a broader illness in which symptoms occur because they are generated by a carefully orchestrated, stereotyped, multi-system response to infection and injury.
Case Report: Overlap Between Long COVID and Functional Neurological ...
January 28, 2022 — Introduction. The severe acute respiratory syndrome Coronavirus 2 (SARS-CoV-2) has been associated with a broad range of clinical manifestations including fever, respiratory, cardiovascular, gastrointestinal, and neurological symptoms during the acute phase of the disease ().Long lasting symptoms, such as fatigue, dyspnea, cognitive dysfunction, and sleep disorders have been described in a ...
How Neuroinflammation May Be Knocking out the Muscles in Long COVID, ME ...
Long COVID Is Not a Functional Neurologic Disorder - MDPI
July 22, 2024 — Long COVID is a common sequela of SARS-CoV-2 infection. Data from numerous scientific studies indicate that long COVID involves a complex interaction between pathophysiological processes. Long COVID may involve the development of new diagnosable health conditions and exacerbation of pre-existing health conditions. However, despite this rapidly accumulating body of evidence regarding the ...
Overlooked Neurological Features Present in Long COVID: Svetlana ...
May 13, 2024 — The director of Dysautonomia Clinic talked about advocating for recognition and research NeurologyLive
Comentários