Four types of Fatigue May 12th CFS/ME Awareness PENE


What it is:
The term PENE didn’t exit prior to it’s début in the ICC ME publication. It is an attempt to create a very unique type of fatigue category and is being put forward as the defining symptom for ME. There are rumors that the IACFSME group is negotiation with the CDC for the creation of the ME category and a move of a set of patients to this designation under the coding of G93.3. According to the rumors the CDC wants to keep the CFS designation, the Reeves Empirical definition and the data sets from Wichita and Georgia. However, they have agreed that those persons who have a viral onset can be moved to the new category. In an effort to keep the ME category as broad as possible the IACFSME group wrote the definition of PENE to be somewhat open and a little vague in hopes of being able to catch more patients into the ME definition than the more narrow definition currently being demanded by the CDC. However all of the above is rumor and supposition and has no supporting evidence.

The definition for PENE is as follows:

A.Post exertional neuroimmune exhaustion (PENEpen’-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 as follows:

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, an be debilitating and cause a relapse.
2. Postexertional symptom exacerbation: e.g. acute flu-like symptoms, pain and worsening of other symptoms.
3. Postexertional 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.

The easiest way to understand this definition is that it requires two things a “neurological” and an “immune” response such as;

  • Swelling of the lymph nodes going from behind the ears, down the neck, across the collar bone, upper chest, under arms and groin area. The nodes are enlarged, palatable except for the groin area and tender.

  • Often there is swelling along the spine from the base of the skull to the just between the shoulder blades with a springy or spongy feeling to the swelling when pressed.

  • Sore throat.

  • A significant lack of mental activity, that includes self talk, ability to form coherent thoughts, to speak or understand sentences.

  • Light sensitivity, sound sensitivity.

  • A flu like feeling without fever.

  • Ataxia, problems with balance, walking, navigating walls and furniture.

Who gets it:
Nearly everyone who has ME will “earn a PENE” from time to time. Either we just need to get something done and there is no one to do it for us or we simply get tired of living life inside our tiny envelope and decided to ‘just do it’ this once. From graduations to weddings to dealing with aggravating medical personnel, sooner or later we all experience what many call a “crash”.

Current research by the Dr.’s Light suggests that this unique form of fatigue may actually be brought about by a cytokine or chemokine storm that is trigged by over exertion. This means that body response by creating huge piles of inflammation creating chemicals that damage the body. Eventually within 24 to 48 hours they burn up and the equilibrium is restored. PENE is different from PEM in that PEM is a lack of energy in the short term with no immune component. PENE however will look much more like a flu as well as having a lack of energy and difficulty with neurological function.

What you can tell your doctor:
Since this is a totally new term it is likely completely unfamiliar to your doctor. Make sure to take a copy of the International Consensus Criteria for ME with you if you want to talk to your doctor about this aspect of your illness. This is particularly important when the response from medical personnel is to just exercise more!

Exercise itself is a good thing in the life of ME patients but exercise is measured within the confines of the energy envelope that you have to work with. Going outside of that envelope will cost you and going outside of the envelope consistently could land you in a much lower level of function in the long run.

If taking a bath leaves you in the bed for the next two days with sore throat and dizziness then your envelope is Sever. Exercise is out of the question or may be limited to stretching your arms over your head for the next year.

What can be done about it:
Unfortunately at this point in time the only option here is to focus on resting and dealing with the changed circumstances in your life. As you learn to cope with the illness through trial and error you can some times choose to ‘earn a PENE’ and still stay on an upward track. But PENE is best keep for those rare circumstances in life that just can’t be avoided.


Thanks for these 4 posts, George. Good stuff. We become connoisseurs of fatigue and of pain, recognizing different qualities and types. Unfortunately, we are limited in our ability to convey those subtle differences both by vocabulary that uses one word to express multiple experiences, and by a lack of shared experience with our listeners, including doctors. That is, doctors may think that they know what fatigue is, based on their own experiences of being tired. They may recognize quantitative differences, on a scale from 1 to 10, but they lack the personal experience to understand the qualitative differences that we experience.
Exactly IX! Most think Chronic Fatigue Syndrome = having fatigue all the time. But that's not it at all. It's having layers of Biological illnesses that each have fatigue as a component. If every biological illness represents 20# of fatigue it adds up really fast! On the other hand if you can talk about, suss out and treat each biological illness you can lighten the fatigue load.

For instance if you have POTS that's a biological illness with "fatigue" as a part of it ;that's 20# .Then if you have a Flare that's another 20#, Then add an inability to reach REM sleep, another 20#, MCS or Allergies to foods and chemicals that you may not even be aware of, add another 20#. On top of that the PEM that may be an immunological response is a 20# weight we have to live with every day until the cause is found. So in no time at all you are dealing with 100 pounds of fatigue, much of which could be mitigated with a little intervention here and there. Take care of the POTS, help with sleep, do an allergy test and make it thorough and you begin to lighten the load!

So yeah, (grins) that's kinda what I was goin' fer. Some way to define each type, write it up, get patients to tweak it, send it to the IACFSME folks and see if they could or would be interested in it as a pamphlet for doctors?????
Late to the party, as usual, but where does all of this leave those of us with exhaustion that requires a long recovery period of 24 hours or more but does not include neuroimmune symptoms? Actually, that is what I thought PEM is, which proves your point that a better delineation of terms is needed.
Hi, Bluestem
Very good question. Sorting out and teasing out the type of fatigues that individuals experience is really tricky. There are a lot of fatigue states, way more than what I've written so far. For instance there is the fatigue of not reaching REM sleep. Often the body only reaches REM sleep every other day or every third day causing PWME's to experience far more profound fatigue on the days in between. It's unfortunate that no sleep studies have been done with this illness.

There is also fatigue from metabolic problems. The mitochondria become damaged and unable to recover the ATP cycle and produce energy on a cellular level. This I think is what happens in the very sever There was a wonderful paper earlier this week that described how Human Herpes viruses do this. In this case it means that the cells in liver, kidney, pancreas as well as blood and lymph are unable to make the energy necessary to do their jobs. If you body is struggling to produce the energy necessary to simply breath, digest and keep the heart beating any additional energy expenditure can leave you in a world of hurt. However, there is a possibility that if you rest aggressively for a day that the next day would allow you to expend a bit of extra energy. This in essence is PEM but a very specific type. (big grins)

Part of the problem with ME is that it sorts a very specific subtype out of the CFS category. But CFS is a big category. It may well include people who have Mitochondria damage, people who have not been diagnosed correctly with Lyme, cancer, MS, ALS, Lupus, organ failure and lots more.

PS: BLUESTEM; It sounds like you may be a good candidate for mitochondria testing? What are your chances of getting that done?
My chances of getting mitochondria testing are probably not good. I live in a very rural area and do not have insurance.

P.S. Did anyone ever tell you that you have really cute ears?

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