The PCA comes with similar pathological somatic changes to the patient's brain (amyloid plagues etc) to Alzheimer's or CJD. There are suggestions that Alzheimer's as well as e.g. Multiple Sclerosis can have an infection in the background - particularly it's been suggested that an infection by Chlamydophila Pneumoniae (CPn) is a possible co-factor in those illnesses (symptom-based descriptions). CPn is a bacteria that can enter into the host's cells (= an intracellular parasite) and pass through membranes, such as the blood-brain barrier... Another similar intracellular parasite is the Borrelia Burgdorferi, generally known as the "Lyme disease"... and the Lyme disease can also cause "neural symptoms", especially if misdiagnosed / untreated, and if accompanied by other co-infections (such as CPn, but there are others). Both these bacteria cause persisting and relapsing infections, have several life stages, can hide from the host's immune system to some degree, can survive simple antibiotic cures etc. If you want to know more, google for Brian Balin on CPn vs. Alzheimer's, or David Wheldon on CPn vs. MS - or just head over to cpnhelp.org.
Why I'm writing all this: This last summer I've gone through an undisputed and properly diagnosed infection of Lyme Disease. And, about four years earlier, I had a nasty case of protracted Bronchitis followed by some unspecific symptoms that make me think of CPn (at the time I didn't manage to persuade my doctors to test me for CPn). When my doc diagnosed the Lyme Disease, he gave me a 10-day cure of Doxycycline and as far as he was concerned, I was "cured". Well the beautiful erythema on my back was gone - so far so good. During the Doxycycline cure, I was observing interesting "side effects" - probably due to the antibiotic having fun with the Borrelia and possibly CPn. And, as I was not entirely persuaded that this was over, I was looking for ways to supplement my doctor's simple batch of ATB.
The general advice for CPn and Borrelia is... before you scramble to get the combined ATB protocols, first try helping your own immune system to get rid of the bacteria (or whatever it really is that you have) on its own. Help your immune system help you.
There are obviously the general diet improvements (lots of fruits and vegetables), possibly a bit of sunbathing (for vit.D) and "controlled overheat" to speed up your immune response (a sauna or even a hot bath, if your cardiovascular system can take it). But most importantly, there are pills to help you. There's something called a "1,3/1,6 Beta-Glucan" - which BTW is a poly-saccharide
It is supposed to increase and "coordinate" the activity of macrophages, with a chain of follow-up alignments in the immune system. The result should be a non-specific improvement in immunity (perhaps more against bacteria than against virii) and "general garbage removal" in the blood stream. I use the Glucan in the form of a daily 200mg capsule, made by some local brand (likely not available in the U.K.) and it's not an approved medicine, it's sold as a harmless placebo-grade "food supplement" (approved by the foodstuffs safety office). It's said to work best if combined with a hefty dose of Vitamin C - some sources (around cpnhelp.org) suggest up to 1 g of vit.C per day, I use a single 500 mg "gradual release" capsule of Vit.C per day. And my third daily pill is some vit.B complex, again a rather hefty dose, again to help improve immunity (co-effect with the others). The glucan is said to be harmless and the two vitamins supposedly don't have any ill effects either, and are difficult to overdose with (they are quickly released in urine). When I catch a cold, I add NAC to the mix: 600 mg per day (2x300 actually), which is the recommended daily dose. I don't use NAC all the time, for fear of some rather theoretical side effects (see the leaflet packaged in). NAC, apart from mechanically easing some itchy symptoms of the cold, is a strong anti-oxidant (just like vit.C), is directly toxic to CPn in some of its life forms, and doesn't have a problem to pass cellular membranes and the blood-brain barrier. It also supposedly alleviates secondary porphyria in ATB treatments of CPn (which is irrelevant here). NAC is a fairly simple substance.
The pills are best taken with a major daily meal (the lunch in our culture) as especially the vit.C is a bit heavy on the stomach if too concentrated (it's sour). As for NAC, avoid brands that include synthetic sweeteners in the pills - these cause stomach trouble to some people (apparently including me). I have good experience with Mucobene NAC. If I miss the lunch, the pills go down well with fruits and vegetables.
I believe I do percieve a difference. I'm generally less tired, any respiratory infections feel very subdued and quickly over, any other infections are next to non-existent. My cholesterol levels went somewhat lower. I got rid of some varied minor symptoms that I attributed to CPn (started to occur after that strange bronchitis) - some of these were "neural". Considering that I'm still relatively young (well 38) and fit, it's all close to placebo-level and wishful thinking. Difficult to tell exactly. I don't feel like a hypochondriac - I consider myself almost perfectly healthy. I do feel like a junkie, taking the three hefty pills with every lunch... well it's better than giving up altogether and waiting what happens.
Perhaps some of this might help Sir Terry to keep typing away for a few more years.