Posted 1/31/2009 1:53 PM (GMT -6)
I have a similar problem, and have gained almost 50 pounds since I began feeling ill in May 2007.
A potential mechanism causing this reaction could be due to inflammatory cytokines, which are high in many people with chronic illnesses. Apparently these can bind to leptin receptor sites in the brain, which can cause disregulation of the hunger mechanism, see for example:
As this site also discusses, neurotoxins could play a role in this biochemical pathway. Some recent research suggests that Lyme bacteria do produce neurotoxins. Ritchie Shoemaker is an MD who is the major proponent of this toxin hypothesis; there are mixed reviews of his Lyme treatment protocol, but based on what I've read to date some people find it very helpful. At any rate, it is pretty well accepted amongst LLMD's that the production of inflammatory cytokines is increased in Lyme patients (not sure if they agree if it's due to biotoxins or some other immune reaction). Disregulation of the thyroid and leptin hormonal pathways are two results of this process which could explain appetite changes and changes in ability to loose weight.
There is a lot of info on the internet about this. I know a little bit because for a while I thought that my symptoms might be caused by mold toxin exposure (I work in the humid tropics for my research, and our research station is utterly overrun by mold in the wet season. It probably doesn't help that the house where we live has asbestos in it, too! I had to start sleeping outside in a hammock rather than inside in a bed!) It might still be a factor, but I think having Lyme would probably be more serious than mold exposure -- though the latter can't help!