Is there someone out there who can describe a metabolic trap?
Without the details of the biochemistry any explanation will be vague. I started thinking about metabolic traps 25 years ago. I presented a paper to an ME/CFS conference in '99 on one type of trap, which was later shown to be wrong.
Lactic acidosis is perhaps a case example. In lactic acidosis, excessive lactic acid overwhelms the acid buffer in the blood and the then alters the blood pH toward acid. As this happens a chemical in red blood cells has an altered rate of production, that leads to less oxygen being supplied. Less oxygen leads to worse oxygen metabolism, and hence more lactic acid.
Now in this case that means that lactic acid leads to even more lactic acid, until after a few days its fatal if untreated. ME would have to be different. My guess is something gets depleted, possibly even NAD or some other energy metabolite, and then the body is incapable of making enough NAD to reverse the situation, since NAD is needed for energy production and you need that energy to do things like regulating metabolites or making enzymes etc. It might not be NAD though, that is only an example.
So a trap would be a metabolic state where things are so bad that the capacity to reverse that state to normal is gone. In chaos theory this would be a pathological strange attractor.
Similar theories have surfaced on patient forums regarding methylation, and methylation traps, which I have not looked at in detail.
For a more everyday analogy, its like falling into a deep well. You know freedom is just a few feet away, but you cannot climb the walls of the well, or at least not easily. Some might succeed, hence the rare recoveries or temporary remissions. In a temporary remission its like you almost climbed out of the well but then fell back in, perhaps injuring yourself further in the fall.
Now a healthy person might have a ladder, or stepping stones, or the well is very shallow, and so they easily get out of it when an infection or other physical insult resolves.