As I understand the issue, most of the symptoms of a disease actually come from efforts of the body to fight it off. Fever, inflammation, mucous formation: all of these are intended to help fight off things that don’t belong there. If you had none of these defensive elements, you would simply, in some cases, keel over and die when the disease reached a critical mass. That is my guess, although disease pathology is not something I know much about.
Cancer can spread quite far without any symptoms at all. I think of Randy Pausch, whose Last Lecture was so well known, who was the image of health even when he was destined to die.
Draw an analogy with emotional energies. Can it not be that those who most manifest symptoms are in fact those who are trying to fight something off? And those who manifest nothing are most sick, when not healthy?
Here is a principle I think works: successful efforts at healing are generally characterized by a worsening of a condition prior to improvement. And if you can’t worse an “element”, it may be it is recalcitrant to healing.
These are high level, perhaps wrong ideas. I am just playing with metaphors. You can kick this pile of blocks over if you want.