Talk:Myalgic encephalomyelitis

Other diagnostic criteria
This section should be moved to the Chronic Fatigue Syndrome page. While some countries, especially following the WHO classification use these criteria they do not call the illness ME but CFS or occasionally ME/CFS.

The Oxford criteria was developed by BPS proponent Michael Sharpe and clearly are for Chronic fatigue syndrome only.

I didn't notice the Nightingale definition for ME here. notjusttired (talk) 14:26, 7 February 2019 (EST)

Progressive, persistent or improving evidence
According to this study 15.9% were found to have a progressive course, others were found to have some time without symptoms (relapsing and remitting), fluctuating, or be improving our staying the same. I would be very interested in any similar research, especially on improvements for those ill a number of years.

I think if anything "persistent" would be a better word. Unsure of recovery rates. notjusttired (talk) 13:53, 7 February 2019 (EST)

Removed "progressive" because ME doesn't consistently present as progressive. Indeed, many cases show improvements over the disease course. Kmdenmark (talk) 09:37, 7 February 2019 (EST)

Need to add section on disability / spectrum illness / % who can work --JenB (talk) 21:30, 7 July 2018 (PDT)

Am doing major clean-up trying to: – shorten introduction to the most basic information and move specifics to subsections later in the article – shorten subsections by linking to or creating subsidiary pages using "main article template" – removing most references to "So-and-so" says

Will still need to correct some journal citations so they are in proper journal format, but this will be much easier/more efficient once the Citoid extension is installed, which I think should happen in the next few weeks.

--JenB (talk) 16:34, 7 July 2018 (PDT)

This article was copied and pasted from an old disapedia article. It will probably need to be edited for length, with the introductory section moved later so that the table of contents is closer to the top of the page. It also has no citations. Some citations can be found at the bottom of this page: http://arainbowatnight.com/whatisme/ Still other facts are probably not cited at all. Lastly, other paradigms of what ME is will need to be incorporated. Its relationship to CFS will need to be described. --JenB (talk) 16:30, 30 November 2015 (PST)

Useful? http://www.meaction.net/2015/12/10/norwegian-researchers-ask-what-exactly-is-m-e/ Olliec (talk) 03:31, 13 December 2015 (PST)


 * I think it's time to overhaul this page. I know if I do it I will wipe it and start very fresh and that probably won't be popular so I will leave it to others.  But it's time.--DxCFS (talk) 14:53, 8 August 2016 (PDT)


 * I don't think it's a horrible start. It could use some cleanup and citations, but I don't find it terrible as is. If we do make radical changes to it, I think we need to keep it free from CFS based research as much as possible. Analogue (talk) 18:49, 8 August 2016 (PDT)


 * I can barely understand it and I have had the disease for decades. Plus when people are sick and first learning it isn't an easy read.  Then there are journalists and caretakers who don't really want to sit there and read and read.  There are no links for the citations because it was a cut and paste.  I agree, it has to stay just ME without CFS because the CFS and ME/CFS pages take care of that.  Just a notation of CFS and its relationship to ME being described as Jen stated above is fine and would take just a couple of sentences.  They are both seriously marginalized diseases which usually come on with a viral/bacterial event or mono/mumps so that is one way it could be explained how they relate to one another as well as defining symptoms of PEM. Outside of that the reader can be given the list of criteria to see what the criteria are looking to diagnose. But I don't know if I am the one to take it on because I really pretty much would wipe it clean and start over and take a few days/weeks bringing it together. All the information we need is already on MEpedia under the Disease History and the Primers and so on it is a matter of bringing it together in an easily readable format.--DxCFS (talk) 19:56, 8 August 2016 (PDT)

Cut to find a better place to include this information. Because immune-related symptoms are common, the immune system was suspected of being dysfunctional or responding inappropriately to specific viruses, leading to the proposal of the alternative name, “Chronic Fatigue Immune Dysfunction Syndrome” (CFIDS).--DxCFS (talk) 10:51, 15 December 2016 (PST)

-

I have not found anything to support this statement even though a citation is indicated and if buried in a PDF document should really have Pg. number indicated: The initial acute phase illness most often occurs in summer with a 3-5 day incubation period and during this period is said to be highly infectious (3).--DxCFS (talk) 11:27, 15 December 2016 (PST)

-

Sensory issues included this line: which has been termed “The Mall Effect” due to its particular provocation by the stimulus of a busy shopping mall. It's a nice line but I have not found any researchers describing sensory overload like this.--DxCFS (talk) 11:50, 15 December 2016 (PST)

-

I left this in tact but I think this was from Hillary Johnson's book and if so should probably be cited better and perhaps with quotes or as an excerpt. The second paragraph seems to site her work but is it a sentence, a paragraph or everything under CDC Intervention.

CDC Intervention
In 1987, researchers from the US Centers for Disease Control & Prevention (CDC) decided to treat the Lake Tahoe outbreak of M.E. as well as other M.E. outbreaks from the mid-1980s as an entirely new illness, yet another decision based on a complete lack of patient examination. It was only after the doctors managing the epidemics used over $200,000 of their own money to fund MRIs, that they found their patients had brain lesions indistinguishable from those found in people with AIDS.

Nonetheless, these findings were dismissed because they were not present in all patients and in 1988 the CDC christened the illness chronic fatigue syndrome (CFS) instead of ME, effectively because three ME experts left the committee meeting early due to (1) a lack of patient information and (2) the remaining members’ preoccupation with Epstein-Barr virus, which was biologically incapable of causing the outbreaks due to the virus’s extensive latency period. CFS is a highly contentious concept to patients and specialists. Because of the similarity in terminology, CFS is often confused with “chronic fatigue”; many believe this to have been intentional for the benefit of disability insurance companies. (Osler's Web, Hillary Johnson, pp 217 – 219).

In 1993 the term chronic fatigue syndrome was added to the alphabetic list of the WHO ICD classification under R53.82 “Symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified.”

Although neither CFS nor its criteria were developed to replace ME, many, particularly in the psychiatry field, falsely promoted the notion that ME was synonymous with CFS. The first CFS criteria (Holmes criteria) published in 1988 by Holmes (5) were in fact created “to provide a rational basis for evaluating patients who have chronic fatigue of undetermined cause.”--DxCFS (talk) 12:22, 15 December 2016 (PST)

- Moving from page here.

Although more than 50 years of research and clinical observation informs knowledge of ME pathology, its exact cause remains unknown and more research is required, particularly for treatment.

-

Moved from front page.

Current theory suggests ME results from a persistent viral infection and/or attacks by an individual’s immune system on the nervous system, musculoskeletal system, and blood vessels.--DxCFS (talk) 13:52, 15 December 2016 (PST)

-

Moving to Discussion Pg as these are symptoms that are valid but citations are needed and would fit better under symptom information. Perhaps finding a paper or research information that lists these as symptoms can be found. NORD has a good symptom list but the paragraphs would need to be reworded to fit their information.

ME can cause a wide variety of symptoms, including changes in sensory tolerance, visual problems, exertional muscle weakness, difficulties with coordination and speech, severe fatiguability, cognitive impairment, problems with balance, subnormal or poor body temperature control, and pain. ME will cause a degree of impaired mobility and disability in all cases. The degree of impairment and complexity depends on the degree of diffuse brain injury and end organ involvement.

Myalgic Encephalomyelitis affects the brain and spinal cord which control the body and allow thought and sensory processing, causing dysautonomia, impaired thinking, and loss of internal homeostasis, the process whereby the body maintains a consistent internal environment in response to external stressors. Cellular metabolism and communication is disrupted, causing inefficiency in all biological processes. This includes the cellular mitochondria which process fuel to make energy, resulting in a deficiency of adenosine triphosphate (ATP) with a chronic, severe, measurable loss of sustainable strength on exertion.

-

This is the link that seems to have the information that has been posted here. https://arainbowatnight.com/whatisme/

-

Probably correct, but no research or clinical documentation online. I have also found these exact words used for MS and some other toxic disease so I fear someone may have found it to be a good neurological phrase that very well may fit our disease but you can't say for certain without a researcher or clinician stating so, otherwise we look like we are just plucked a nice sentence from two other diseases and put it in a blog.

If Ramsay himself said it then we would need to state that and have direct citation. Between relapses, symptoms may resolve completely with sufficient rest, but permanent neurological problems often persist, especially as the disease advances.

- Cut from Epidemiology Heading

''Currently ME is less epidemic and more endemic than in previous decades. ME outbreaks still occur even though the epidemics are no longer recorded or studied. Dr. Byron Hyde mentioned receiving “reports of over sixty” ME outbreaks from 1988 to 2003, which were “no longer figured in the literature” and “were not given any mention in the International Consensus Criteria.”''

It is in this document: http://www.hfme.org/methemedicalfacts.htm - because a google search of this information brings it up but I cannot find it buried in here and when citation created by whomever can find this information should note the heading and perhaps paragraph that states this.--DxCFS (talk) 09:57, 16 December 2016 (PST)

- I get the feeling at least part of this information was taken from Hillary Johnson's book but only one citation exists. Until this is clarified (I think there need to be quotes and excerpts of parts from her book) I moved all of History here. And perhaps some was taken from Thirty Years of Disdain which would also need to be noted. I think someone could come up with a better history than this all together but I will just leave this here for someone else like Ollie or Jen to make a decision. It isn't a great read the way it is.

First descriptions
The first definitive description of an illness resembling poliomyelitis was by Gilliam after the 1934 Los Angeles outbreak. Careful clinical observation in all the epidemics repeatedly found reproducible signs and a distinctive pattern of CNS and sensory nerve involvement, muscle weakness with pain or tenderness, and emotional liability with a chronic, relapsing course.

In the 1950s, the public eye was caught by several outbreaks of a mysterious illness that incapacitated communities, often in hospitals. In the Iceland epidemic it was noted patients who contracted the illness developed immunity to poliomyelitis, suggesting confirmation of an association.

Autopsy findings on experimentally infected monkeys during the Adelaide epidemic led to the conclusion that the disorder was caused by inflammation of the brain and spinal cord. Accordingly, names such as atypical polio and Akiyuri disease were replaced in 1956 in the UK by the term Benign myalgic encephalomyelitis. However, autopsies on humans have revealed only evidence of infection, notably in the brain, heart, and skeletal muscle.

WHO Classification
ME has been classified by WHO as a disease of the Central nervous system under ICD-8 since 1969.

In the ICD-10, ME is the only disorder listed in the tabular classification under G93.3, Postviral fatigue syndrome (PVFS).

Despite the increasing prevalence of non-epidemic cases, the disorder was soon dismissed by some as mass hysteria due to the 1970 McEvedy and Beard review, in which no actual patients were examined.

I would remove "It has been classified by the World Health Organization (WHO) as a neurological disease since 1969" because its obviously physical and cognitive. Its tempting to clean up that line or move it but we would not keep a line that says PACE classed it as psychosomatic hence it is even with cleanup.

CDC Intervention
In 1987, researchers from the US Centers for Disease Control & Prevention (CDC) decided to treat the Lake Tahoe outbreak of M.E. as well as other M.E. outbreaks from the mid-1980s as an entirely new illness, yet another decision based on a complete lack of patient examination. It was only after the doctors managing the epidemics used over $200,000 of their own money to fund MRIs, that they found their patients had brain lesions indistinguishable from those found in people with AIDS.

Nonetheless, these findings were dismissed because they were not present in all patients and in 1988 the CDC christened the illness chronic fatigue syndrome (CFS) instead of ME, effectively because three ME experts left the committee meeting early due to (1) a lack of patient information and (2) the remaining members’ preoccupation with Epstein-Barr Virus, which was biologically incapable of causing the outbreaks due to the virus’s extensive latency period. CFS is a highly contentious concept to patients and specialists. Because of the similarity in terminology, CFS is often confused with “chronic fatigue”; many believe this to have been intentional for the benefit of disability insurance companies. (Osler's Web, Hillary Johnson, pp 217 – 219).

In 1993 the term chronic fatigue syndrome was added to the alphabetic list of the WHO ICD classification under R53.82 “Symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified.”

Although neither CFS nor its criteria were developed to replace ME, many, particularly in the psychiatry field, falsely promoted the notion that ME was synonymous with CFS. The first CFS criteria (Holmes criteria) published in 1988 by Holmes (5) were in fact created “to provide a rational basis for evaluating patients who have chronic fatigue of undetermined cause.”

CFS research and Psychiatric paradigm
Research increased after the CFS criteria were further relaxed in 1994, but it was criticized for its over-inclusiveness. With all objective signs now expunged, the obvious possibility of misdiagnosis bedeviled clinical and research work. Lacking a diagnostic laboratory test of any kind, CFS is frequently misdiagnosed in patients presenting symptoms to other similar biological conditions, infections such as Lyme disease (for which standard testing produces an extremely high rate of false-negatives) or Epstein-Barr virus (the cause of glandular fever/infectious mononucleosis), or psychological conditions.

A lack of information and awareness has led to both ME and CFS patients being stigmatized, sometimes as hypochondriacs or lazy, yet at other times as over-active and perfectionist.

More accurate criteria should help to increase homogeneity and identify pathology. It has also been noted that some journals operate pro-psychiatric editorial policies, resulting in a narrow range of opinions and undermining the physicians’ understanding of the illness.

A major recurrent criticism of CFS is that it does not make post-exertional malaise or muscle weakness an essential criteria, thus leading to the uncertainty and controversy over the appropriateness of physical rehabilitation programmes.

ME Redux
Recent research on CFS may be relevant to ME. For example, studies have revealed pathologically delayed recovery of muscle strength, cardiac and vascular abnormalities, and defects in cellular metabolism. Neurocognitive dysfunction has been objectively observed; and physiological abnormalities relating to immune activity, gene expression, oxidative stress, and nervous system have also been found, plus many psychological and psychiatric studies have also been done.

The CDC now recognizes CFS as a serious illness but also [listed] ME as a differential diagnosis on their website [until 2011], reflecting the incompatibility of the traditional definitions by stating the following:

“Various terms are often used interchangeably with CFS. CFS is the preferred term because it has an internationally accepted case definition that is used in research and clinical settings. The name Chronic Fatigue Immune Dysfunction Syndrome (CFIDS) was introduced soon after CFS was defined; there is no case definition for CFIDS, and the name implies an understanding about the pathophysiology of CFS that does not currently exist. Chronic active Epstein-Barr virus (EBV) infection (chronic mononucleosis) was thought to be the cause of CFS during the 1980s, and this association is now known to be rare. However, post-infection fatigue syndromes have been associated with EBV and other infectious agents. The name myalgic encephalomyelitis (ME) was coined in the 1950s to clarify well-documented outbreaks of disease; however, ME is accompanied by neurologic and muscular signs and has a case definition distinct from that of CFS” (Centers for Disease Control and Prevention).

Patients and specialists alike have long lobbied for a name and definition change or reversal of “CFS”. In January 2007, the American “CFS Name Change Advisory Board” consisting of doctors Lucinda Bateman, David Bell, Paul Cheney, Leonard Jason, Nancy Klimas, Charles Lapp, and Daniel Peterson–several of whom were present in the 1980s outbreaks–agreed that “CFS downplays the severity of the disease and is hurtful to patients” and publicized their deliberation that CFS should now be termed ME. However, no statement was made on definition, and considering the slew of misdiagnosed individuals accrued within the “CFS” umbrella since 1988, other doctors, researchers, and ME experts insist that the CFS illness described by the CDC and Oxford criteria in the UK, no longer represents ME. There are historical reasons for choosing myalgic encephalomyelitis as the name, however the acute post-viral onset, brain inflammation, neurological damage, and extremely specific pattern of muscle fatigue inherent in ME are not a required part of any CFS diagnosis. Multiple studies from Jason et al. show most people with a CFS diagnosis do not have myalgic encephalomyelitis.

In 2003 a group of international specialists published the consensus definition of an illness now termed ME/CFS the criteria of which, including CNS and exertional signs, was more like that of ME than CFS. However, there is no ICD code for “ME/CFS” or “CFS/ME.” Although ME remains under ICD G93.3 as “benign myalgic encephalomyelitis,” Professor Malcolm Hooper (6) explains: “The word ‘benign’ was used because it was thought at the time that the disorder was not fatal (as poliomyelitis could be, with which it had some similarity), but it was quickly realised by clinicians that ME was not a benign condition, as it has such high morbidity… By 1988 clinicians had stopped using the word ‘benign’ and referred to it as ME, the first to do so being Dr. Melvin Ramsay.”

The ICD-10-CM officially states that ME and CFS are two separate entities, each mutually exclusive of the other. ME is listed as subset of G93.3 Postviral fatigue syndrome under Diseases of the nervous system, while CFS is listed under R53.82 as a subset of Malaise and fatigue. Both entities have “a type 1 exclusion” listed for the other, which is “used when two conditions cannot occur together.” The World Health Organization’s (WHO) International Classification of Diseases (ICD) page for ME explicitly states R53.82 Chronic Fatigue Syndrome as a type 1 exclusion that “should never be used at the same time as G93.3. A type 1 excludes note is used when two conditions cannot occur together.”--DxCFS (talk) 20:20, 16 December 2016 (PST)

-

Except for the blog the ME post came from, I found nothing about ME being Dx for those farther from Equator but rather MS. (I don't even believe the one about MS.)

Since ME seems to be more common in people who live farther from the equator, another theory proposes that decreased sunlight exposure and possibly decreased vitamin D production may help cause ME. This theory is bolstered by recent research into the biochemistry of vitamin D, which has shown that it is an important immune system regulator.--DxCFS (talk) 20:20, 16 December 2016 (PST)

- Environment Tab

I don't think the beliefs about the disease are completely inline with the following two paragraphs anymore. Move them here for others to decide and find research and clinical citations.

The most popular hypothesis is that a flu-like virus or viral infection or retroviral reactivation primes a susceptible immune system for an abnormal reaction later in life. On a molecular level, this might occur if there is a structural similarity between the infectious virus and some component of the central nervous system, leading to eventual confusion in the immune system.

Research has shown that, much like the relationship between HIV and AIDS, the immune dysfunction accompanying ME can lead to temporary or permanent disease progression, regardless of the infection or combination of infections to which the ME sufferer is exposed. Additionally, ME sufferers can be more prone to opportunistic infections.--DxCFS (talk) 21:06, 16 December 2016 (PST)

A Rainbow at Night - Blog no longer exists and could not find these quotes and info in a PDF or anywhere else. Moving here so someone can find info somewhere and cite. Seems very specific so I think it needed to be moved until we can find like information.

"The later course of ME is difficult to predict, and may either become consistently severe, improve to a plateau, or be markedly relapse-remitting. In some, even prolonged severe incapacitation can be relieved by unpredictable remission, although relapse is always possible. The degree of impairment and complexity depends on the degree of diffuse brain injury and end organ involvement."

There are no standard subtypes. Some researchers and clinicians have proposed distinguishing between a relapsing-remitting and progressive course. [citation needed] However, it is difficult to distinguish between natural variation in the population of ME patients who might share a common disease process but owing to individual, genetic, or environmental differences, have different symptom clusters or disease course versus heterogeneity created by imprecise criteria and misdiagnosis.--MEcfsFMS (talk) 22:19, 7 September 2018 (EDT)

Immune System Info - Cut and Put Here Until Citations Are Found
According to a strictly immunological explanation of CFS, the inflammatory processes triggered by T cells create leaks in the blood-brain barrier (a capillary system that should prevent entrance of T-cells in the nervous system). These leaks, in turn, cause a number of other damaging effects such as swelling, activation of macrophages, and more activation of cytokines and other destructive proteins such as Rnase-L. Channelopathy, a reduced ability to move metabolites in and out of cells has been implicated in this process. This may also be applicable to ME.--77.111.245.13 20:20, 25 February 2019 (EST)

Cutting CNS info until citations are found
Radiological research on ME has shown hypoperfusion of the brain stem and an abnormal response to exertion, but research on CFS is often inconsistent and must be interpreted with caution. For example, some research stated that a reduced volume of grey matter may be a result of a lack of activity and is reversible with cognitive behavioral therapy (CBT).--77.111.245.13 20:24, 25 February 2019 (EST)

Chronic Infection Info Cut until better citation found
Some evidence shows viral infection of muscle and brain in at least a proportion of sufferers. This triggers inflammatory processes, stimulating other immune cells and soluble factors like cytokines and antibodies. A model for late ME has been proposed analogously to post-polio syndrome in which repaired nerve tissue forms inappropriately [The Late Effects of ME: Can they be distinguished from the post-polio syndrome?]. --77.111.245.13 20:26, 25 February 2019 (EST)

Cardiovascular citations needed for this info
Hemodynamic abnormalities are widely found, including serum and RBC hypovolemia, neurally mediated hypotension, (NMH) and cerebral hypoperfusion. Vascular and endothelial abnormalities have been published by MERUK. However, none of these studies used research criteria for ME so the results may not be applicable to ME.

Some cardiologic features such as cardiac insufficiency, inverted T-waves and myofiber disarray have been reported in CFS and recently added to by findings of reduced Q-value. This has led clinician and researcher Dr Paul Cheney to posit that CFS is form of partially compensated cardiomyopathy in which orthostatic intolerance and rapid fatiguability are secondary protective mechanisms. Due to the heterogeneity of the population, a single cause is unlikely, but one-third of people with ME have abnormalities when tested with Holter monitors.--77.111.245.13 20:27, 25 February 2019 (EST)

Course and prognosis info - No citations
The following is true but, all except #4 have no citations are available.

1. PEM episodes and temporary or permanent reduction in functional ability are often a result of over-activity, but can occur without warning with no obvious inciting factors. Exposure to increased sensory information in light, sound, and movement can provoke a sensory storm.

2. Infections, such as the common cold, influenza and gastroenteritis, also increase the risk for a relapse. Heat and cold can transiently increase symptoms.

3. Pregnancy can directly affect the susceptibility for relapse. Later pregnancy appears to offer a natural protection against relapses, and there are anecdotal reports of postpartum remission. However, pregnancy does not seem to influence long-term disability.

4. About 25% of patients become severe or very severely ill with ME.

Caption under Jen's photo by Signs and Symptoms
I think this isn't as clear as it could be. It mentions POTS, but not that it was likely triggered by ME - that's confusing when next to the symptoms list. Perhaps it should say Jen was misdiagnosed with conversion disorder? Also I wondered whether there should be an update/rephrase since she's in remission and not in need of a wheelchair currently (as far as I know). Currently it says: "Her neurologist diagnosed her with "conversion disorder" (hysteria). When walking home from his office, she collapsed. Jen now needs to use a wheelchair keeping her legs up due to POTS as her blood pools into her legs." User:JenB A further thought I had was whether to request permission to use a photo of Robyn (Doctor with ME), since she's made public a number of pictures of herself using a wheelchair (no idea if related to POTS or ME without POTS). I believe doctors are one of the professions particularly likely to get ME. We seem to be using the same photos on quite a few key pages (most of these are on the severe ME page too). Would a photo of someone with mild ME help with the public understanding that often signs aren't so visible? I think we have one of Whitney when his illness was mild/moderate? ~Njt (talk) 20:06, February 3, 2020 (EST)

== Post Exertional Malaise intolerance to exertion? -- Johnnyd3 (talk) 00:30, July 4, 2020 (EDT) -- Johnnyd3 (talk) 00:30, July 4, 2020 (EDT) ==

"A hallmark symptom of ME is post-exertional malaise (PEM), which is an intolerance to previously achievable cognitive or physical exertion.[5][6][7][8][9][10] "

I always understood PENE/PEM to be an intensification (or worsening) of symptoms after a person has overexerted themselves or been exposed to overstimulation (e.g. talking, lights). It is the result of the person's "intolerance to previously achievable cognitive or physical exertion" but not the intolerance itself. In theory it would be possible for someone with ME who was perfectly cautious to never to get PENE/PEM but obviously they would still have the intolerance to exertion. Alright to separate the two concepts?


 * Perhaps it would be better rephrased. I don't think they should be combined because while they are often treated the same, the wording for PENE is now precise abs restricting, PEM is one criteria amd a bit vague. If activity is several limited that fatigue can often be avoided - but PEM is still going to be met since the person can't do their previous activities. So if you manage to avoid PEM symptoms you still get classed as having PEM because you can't tolerate previous activity levels.

Also image being a marathon runner and international hockey player like Mark Vink. Being totally unable to do his previous activities without PEM may mean he could still do short runs or use the gym. But he's clearly got PENE - he can't even do what an inactive couch potato could manage.He's bedbound. Having just checked the ICC, PENE is not based on a comparison with what you could do pre-illness and it references the immune system. There's 5 characteristics
 * Problems defining PEM by Jason.

A. Post-Exertional Neuroimmune Exhaustion (PENE pen'-e) Compulsory

This cardinal feature is a pathological inability to produce sufficient energy on demand with prominent symptoms primarily in the neuroimmune regions. Characteristics are:

1. Marked, rapid physical and/or cognitive fatigability in response to exertion, which may be minimal such as activities of daily living or simple mental tasks, can be debilitating and cause a relapse.

2. Post-exertional symptom exacerbation: e.g. acute flu-like symptoms, pain and worsening of other symptoms 3. Post-exertional exhaustion may occur immediately after activity or be delayed by hours or days.

4. Recovery period is prolonged, usually taking 24 hours or longer. A relapse can last days, weeks or longer.

5. Low threshold of physical and mental fatigability (lack of stamina) results in a substantial reduction in pre-illness activity level ~Njt (talk) 16:59, July 4, 2020 (EDT)

Image formatting -- ~Njt (talk) 20:25, November 13, 2020 (UTC)
Please do not remove images if there are layout problems since this removes vital information from a page, and prevents the formatting issue from being investigated and fixed. Instead please make a note on talk pages describing the issue, which image is involved, which screen size and device was used, etc. Many issues can be resolved just by altering image layout options. At the moment we have far too many patient pictures and not enough graphical information / factual or research images. User:JenB User:JaimeS User:Kmdenmark User:Fireballsky ~Njt (talk) 20:25, November 13, 2020 (UTC)

Subtypes
I would like to add this info back in, but give it appropriate (limited) weight since there have been several different proposals for subtyping. ~Njt (talk) 20:25, November 13, 2020 (UTC)