It could be related to nerve issues in the gut. This is a good article about
how Lyme can affect the gut:
thehumansideoflyme.net/viewarticle.php?aid=62 There is a lot of information in this article, but here is a couple of excerpts:
"The vagi (10th Cranial Nerves) are major suppliers of the gut's external nervous system and being very long and complex, are vulnerable to neuropathies such as Lyme disease or diabetes which can cause them serious damage." (Personal communication from Neurologist, Richard Rhee, M.D., F.A.A.N., Neptune, NJ)
" Regardless of the site, spirochetes' disturbing symptoms may come and go spontaneously, often temporarily resolving in a matter of hours to days, although resolution does not imply cure. As with Bell's palsy of the face, these gastrointestinal conditions may endure or only partially remit (15). "