quenched
[0] https://www.s4me.info/threads/exploring-the-role-of-galectin...
It's proven to be the case. A repeat cardiopulmonary exercise (2-day CPET) is currently the only widely replicated biomarker for ME/CFS. Only ME/CFS shows a reduction in performance and a lowering of ventilatory threshold on the second day. Anyone else (sedentary, cancer, heart or lung disease, MS, depression) will show an improvement. [1]
A study this year showed a striking effect looking at the metabolites in urine after exercising female ME patients vs sedentary healthy controls. The ME patients just did not excrete metabolites as the healthy controls did. [2]
"This indicates that ME/CFS patients have a general metabolic dysregulation that is part of their exercise intolerance and PEM in which altered metabolic excretion is a contributing factor."
There's also a very simple clinical discriminator between ME/CFS and depression. If you ask a depressed person what they would do if they were suddenly cured, their answer will be "Not sure, I don't know, I can't think of anything, nothing really." If you ask someone with ME/CFS the same question, the response would be "Go to the shops, drive my car, walk on the beach, see my friends... etc".
It's heavily published on and widely accepted as valid by neurologists, but that does not make it true.
The concept with FND is that there is no identifiable structural pathology, but that the neural circuits are dysfunctional, and that this can be fixed with things like cognitive behavioural therapy. This is typically framed to the patient as "the hardware is completely OK, there's just a problem with the software." (As most of this audience would recognise there is very little overlap between how brains work and how computers work.)
However, more advanced imaging techniques, such as 7T MRI are now showing structural abnormalities in these patients, which is a pretty fundamental problem for the above hypothesis. An attempt to rationalise this by FND proponents is made here.[2]
A recent example involves a 10yo child who developed a movement disorder following Covid.[3] Typically these would be diagnosed as functional movement disorder [4][5][6] and psychological therapy advised. However this group showed that in fact it was due to a neuroimmune pathology, with auto-antibodies forming that targeted some portion of the basal ganglia. The patient recovered completely with immunosuppression.
[1] https://www.bmj.com/content/325/7378/1449
[2] https://neurosymptoms.org/en/faq-2/can-people-with-fnd-have-...
[3] https://link.springer.com/article/10.1007/s00415-023-11853-5
[4] https://movementdisorders.onlinelibrary.wiley.com/doi/10.100...
Life-Threatening Malnutrition in Very Severe ME/CFS (2021)
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8070213/
Caring for the Patient with Severe or Very Severe Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (2021)
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8544443/
There are not many mortality studies and few ME patients have had comprehensive autopsies —
Mortality in patients with myalgic encephalomyelitis and chronic fatigue syndrome (2016)
https://www.tandfonline.com/doi/full/10.1080/21641846.2016.1...
Causes of Death Among Patients With Chronic Fatigue Syndrome (2007)
https://www.tandfonline.com/doi/abs/10.1080/0739933060080376...
Somewhat harrowing reading is Whitney Dafoe's account of becoming extremely severe —
Extremely Severe ME/CFS—A Personal Account (2021)
https://www.nature.com/articles/s41577-023-00904-7
https://www.nature.com/articles/s41579-022-00846-2
https://www.frontiersin.org/articles/10.3389/fneur.2023.1090...
Mild ME/CFS is usually associated with around 50% reduction in daily functioning. Moderate will usually lead to people being housebound and intermittently bed-bound. Severe and very severe are associated with a level of suffering that is hard to imagine possible.
An example of someone becoming severe is PhysicsGirl - Dianna Cowern.
The associated severe dysautonomia means that people are unable to sit or stand and often they can not eat or digest. They may require intravenous nutrition. Regrettably there are cases where the disease has not been treated appropriately and young people have died as a result. A recent example is Maeve Boothby-O'Neill and her father Sean O'Neill wrote in The Times with an interview with Maeve's Mother by Dr David Tuller.
https://www.thetimes.co.uk/article/my-daughter-couldnt-be-sa...
https://www.codastory.com/waronscience/chronic-fatigue-syndr...
This is why in the days of processed x-ray films, TV shows would more commonly hang a chest x-ray incorrectly[1], with the (patient's) "left" label on the left instead of the right. It's less common now that the example imaging is digital.
[1] https://screenrant.com/scrubs-xray-gag-joke-deeper-meaning/
The name does it little justice, and fatigue - while certainly pathological and disabling - is not the primary feature. The disease appears unique in terms of an abnormal response to exertion. This has been characterised via two-day cardiopulmonary exercise testing. Healthy controls and even those with other severely limiting diseases will show improvement on day 2, but ME/CFS uniquely shows a reduction on the second day.
Other key features are orthostatic intolerance with demonstration of reduction in cerebral blood flow in the majority on sitting/standing. Neurological symptoms including extreme sensitivity to light and sound explain her blindfold and ear protectors. Many have fluctuating cognitive slowing ("brain fog").
New insights into the metabolic derangements are being gained. Recently[1] evaluation of urine metabolomics demonstrated that healthy sedentary controls excrete many metabolites at 4 and 24 hours following an exercise challenge, while ME/CFS patients do not.
Apart from the devastating effects on patients and the economic impacts of losing so many from the workforce[2], I believe that understanding the immune and metabolic derangements underlying this condition will lead to major insights across many health domains.
[1] https://www.mdpi.com/1422-0067/24/4/3685 [2] https://www.nature.com/articles/s41579-022-00846-2