Researchers find link between nerve damage and long Covid | Hacker News Reader

Researchers find link between nerve damage and long Covid

nn.neurology.org

74 pointsDavideNL39 comments

Note that all patients in this study were presumably unvaccinated, since they contracted COVID between February 2020 and January 2021. Amongst fully vaccinated people, the prevalence of long COVID symptoms seems to be on par with the baseline prevalence in an uninfected population: https://www.medrxiv.org/content/10.1101/2022.01.05.22268800v...

Thanks for the link. Just a note: It is preprint and hasn't been peer reviewed yet. But I really hope these findings are true.

Why would you hope for people to get nerve damage from Covid?

I think you'd have to try really hard to read the parent comment as ungenerously as you seem to be doing.

Clearly they were hoping the statement "Amongst fully vaccinated people, the prevalence of long COVID symptoms seems to be on par with the baseline prevalence in an uninfected population" was true, which means, basically that for vaccinated people the risk of post-viral symptoms is essentially unchanged if they get infected or not.

Note that the tests involved here are objective. The skin biopsy is especially objective and cannot be explained away as psychosomatic. Reduced nerve density as measured by a technician viewing your biopsy through a microscope is about it as objective as it gets.

These measures are also standard tests that have been in use long before COVID existed, so we have a substantial catalog of baseline results by age and demographic to compare against.

As this topic gets more attention it’s going to be increasingly important to emphasize the objective measures and damage that is being found. I’m already seeing public opinion lean toward doubt and dismissal when Long COVID comes up.

Agreed. It’s common for doctors to be skeptical of patients if there’s no test that proves the condition they have, even though absence of evidence is not necessarily evidence of absence. It’s a sign for inquiry at least until certain causes can be ruled out for the still suffering patient; not just lazily diagnosing them with anxiety as doctors are sometimes apt to do.

By creating tests, it gives both doctor and patients the ability to move forward to create incentives for the medical industry to solve these problems. The former so they’re not penalized for questioning the status quo. The latter so they have their concerns properly addressed.

Very important work.

"The skin biopsy is especially objective and cannot be explained away as psychosomatic."

Just to point out, by definition psychosomatic illnesses result in physical (soma) changes that would still be observable in an objective measure. An example would be longterm depression restructuring the brain or suppressing the immune system.

So the change has been objectively observed. The mechanism causing it would still need to be determined to classify it as strictly physical or psychosomatic, although it does rule it out as being strictly psychological.

I suppose some people will find ways to dismiss anything, but the idea that small fiber neuropathy could objectively occur in multiple patients due to psychosomatic illness when it has never been observed in any other mental health issue should be enough to dismiss the idea entirely.

Should we also dismiss the idea that longterm depression restructures the brain or suppresses the immune system just because it hasn't been found in other mental health issues?

Just because something hasn't been found elsewhere doesn't mean it should be casually linked. We need to see the underlying mechanism.

I came down with Bell's palsy just about a month after a Covid infection, which fits what they're saying here. Covid definitely does some weird stuff with your nerves, which is why many people (pre-Omicron) lose taste and smell. EDIT: nope, I was wrong about taste and smell loss resulting from nerve damage.

Were you vaccinated? And how long did the condition last?

I was not, I caught Covid before I was eligible for vaccination. And thankfully the Bell's palsy only lasted about a week.

My symptoms were incredibly mild, I only lost taste and smell for a couple days before they fully returned. No fever or noticeable fatigue.

The loss of taste and smell does not appear caused by nerve damage. It appears to be caused by damage to the cells that support the olfactory neurons ( called sustentacular cells) [1]

1: https://www.cell.com/cell/fulltext/S0092-8674(21)01282-4

Interesting! I wasn't aware of that study.

Could be COVID-triggered, but Bell’s Palsy is different than the physical nerve damage they evaluated in this study. Small fiber neuropathy is more long-lasting or even permanent if the underlying cause of nerve destruction can’t be addressed.

I'm intrigued by the first statement: "Recovery [...] appears exponential".

If it's exponential, then there's a measurable decay rate. Or you could express it as a half life. So what is the half life of COVID after-effects?

I scanned the article for mentions of what the decay rate is, but couldn't find it. That's disappointing, maybe they used the word 'exponential' without knowing what it means.

Generally they just measure recovery time in days on average. It's much simpler and easier to explain to a layman than using half lifes when it isn't necessary

> In addition, 1/4th of human DRG neurons express mRNA for SARS-CoV-2–associated receptors and deploy ACE2 protein. Thus, virus or spike protein fragments may attach to them, promoting formation of antibodies that can also target adjacent neural epitopes.

The paper briefly mentions this, but is there a biological difference in how the body responds to SARS-CoV-2 spike proteins from COVID infection versus vaccine-induced production of these proteins? I feel like this question is often labelled as "anti-vaxx" but it's a valid concern. It could explain some of the rare neurological side effects some people experience from the vaccines. It seems to boil down to some immune response, so it may make sense that vaccine-induced protein generation from within the body produces a less intrusive immune response, but this is just a layman's understanding.

Request: Submissions related to "pain science", neuroplasticity, and chronic pain.

Here's a bit about phantom arm pain.

Rubber Arm Experiment | MAGIC FOR HUMANS https://www.youtube.com/watch?v=xdxlT68ygt8

Seems so crazy. How's this even work?

None of my pop-sci books I've read about the brain touch on pain. And vice versa.

The books I've read about pain (these last two years) approach from psychiatry, mindfulness, and general purpose wellness. Stuff like this https://www.painrevolution.org

All well and good. The techniques and skills I learned actually worked. But I'd really love to know more about the underlying mechanisms. Because right now what I experienced really seems like magic (phenomenon without explanation).

Like I've read about practiced graded motor imagery. But I don't understand it. http://www.gradedmotorimagery.com

Just occurred to me I should look for books about drugs, pharmacology, and pain killers. Maybe that's a ramp to the neurology stuff. Any suggestions?

The rubber arm thing is interesting. It's much like the mirror boxes used to stimulate phantom limbs, and by doing this patients can relax phantom limbs that are permanently 'tensed'. This was created by a doctor VS Ramachandran. He wrote a few books, they're somewhat pop Sci but include a fair bit of in depth knowledge. His book Phantoms in the Brain covers a lot of this. Another book of his, The Tell Tale Brain, is a bit more general but it's also a fascinating looking at how the physical brain and consciousness intersect, especially in regards to disease

Since, as humans, we are not all the same, what is the risk that these people carry? What is their hidden health problem that might have had these issue pop up later in life?

Unless the start looking at each persons genetics and metabolic profiles they will get nowhere. I know this is true because they have been publishing the same stores about ME/CFS and Fibromyalgia for years and they have still gotten no where.

https://meassociation.org.uk/2020/09/medscape-small-fiber-po...

A significant proportion of patients with myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) and dysautonomia may have potentially treatable underlying autoimmune-associated small-fiber polyneuropathy (aaSFPN), pilot data suggest.

There is no one cause of Long Covid. If you re suffering from it you need to look at yourself specifically, personalized medicine is your only hope.

No control group.

The lab tests they used are well established and have well-known reference ranges from healthy controls already.

Small fiber neuropathy is very rare among younger people.

You still need a control group and blinding, as there are a number of ways errors can creep in to studies like this.

It doesn’t need a control group any more than a cancer study requires a control group before it can determine whether or not the cancer patients have cancer.

It's not quite like cancer. They count antibody staining under a microscope, so there are multiple ways that can go wrong. You have a control group to see what % of your control group shows up positive.

Take for example the criteria for POTS: a 30bpm rise on standing. Well, research shows that 80% of control subjects have 30+ bpm rise on standing. I have a 40-50bpm rise on standing, even though I'm incredibly healthy and fit. The article doesn't mention what criteria it used for autonomic function testing, so I'm not saying they used this test. It's just an example of why you need control groups. This isn't cancer...you don't just do an xray and see a big lump!

It is not reviewed yet, I am skeptical as well.

I had some mild peripheral neuropathy symptoms in the days after I cleared my infection (tested negative two days running). Anecdotally seems to fit. Burning sensation in my lower back and legs and left side of my face.

I wonder how they respond to medications or even diets (lions mane mushroom) that promote nerve growth factor, or if it's permanent.

I still think about the HN commentor who told me confidently, "there is no theoretical basis for long-term consequences of COVID-19." [1]

[1] https://news.ycombinator.com/item?id=23875391

That's a bit bold/uncharitable of you. What is the definition of long-term and medium-term? With the average duration of observation being 1.4 years in the study, I could see that going either way. The commenter admits that medium term lung damage is possible.

Their comment was likely consistent with the experts at the time it was posted (July 2020).

And I think you're being too forgiving. They claimed there was not even a "theoretical basis." Of course there's a theoretical basis for a virus causing long-term effects. I suffered from Shingles, just as a for-instance. We'll probably never know how many have had HPV / Cervical Cancer.

And at this point, I have friends who are suffering effects from Long Covid.

At the time, it would have been far more accurate to say, "The evidence doesn't indicate any cause for alarm about long-term symptoms." Not, "there is no THEORETICAL BASIS for long-term consequences."

It depends on how you interpret it, especially "theoretical". I was interpreting it as there being no known theoretical mechanism (in the scope that you need a plausible mechanism of action).

One could say there a theoretical basis for the vaccine causing long term harm. Until there's actually support via an identified mechanism, it doesn't really matter - it's just a guess.

So if there wasn't a factually supported mechanism in July 2020, then there was no theoretical basis, simply a guess that it works similar to some (but not other) viruses.

Wow that comment was wrong in every single claim it made it seems (outside of the claims it cited from somewhere else).

I find there are often mistakes and misunderstandings when it comes to articles relating to the field of medicine on HN. I recall having to explain the difference between intracellular calcium levels and calcium channels in the brain. Perhaps it's a different way of looking at things as there are more math majors than biology majors here. All the specialized knowledge medicine requires certainly doesn't help.

The title says "Patients [plural] With Prolonged Long COVID" but it seems to be just 1 patient?

17 patients:

> Results Among 17 patients (mean age 43.3 years, 69% female, 94% Caucasian, and 19% Latino),

17 with COVID, 1 with Prolonged Long COVID:

> Among 17 patients with SARS-CoV-2 onset between February 21, 2020, and January 19, 2021, treated in 10 states/territories (Table 1), 16 had mild COVID. The one (#9) with severe COVID (1 month stay in intensive care with ventilatory support) had electrodiagnostically confirmed sensorimotor polyneuropathy ascribed to critical care illness in addition to SFN.

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