I wasn't sure where to post this update but this thread on paraneoplastic syndromes (PNS) seemed like the most appropriate place. Am still trying to catch up on PM's and wanted to update those I have not had a chance to respond to yet. Am also hoping this info might help others as I believe there must be others out there like me who have an ME/CFS type illness but remain diagnostically unclear.
Long story short, I tested positive for two rare antibodies: Anti GAD65 Ab, and N-type Calcium Channel Ab. My doctors feel both correlate to my extreme lung weakness/restriction and shortness of breath (which is by far my #1 worst symptom and has been progressive and life altering.) I went to Stanford for autonomic testing which confirmed that I have POTS (which I already knew) and also revealed that I have autonomic neuropathy and abnormal sweating to my feet (which I did not know.)
But more important than the autonomic testing, they ran blood tests which were sent to Mayo Clinic. One of these tests was the PAVAL panel which checks for auto-antibodies which relate to paraneoplastic syndromes (which was a new concept for me.)
@anciendaze can explain this better than I can (and hoping he will correct me if I explain this wrong!) but these syndromes are the link between autoimmune diseases and cancer. One such disease is LEMS (which as I posted above, I most likely do not have) but also links highly with small cell lung cancer. Another example is Myasthenia Gravis (which I do not have) but links highly with thymus cancer (thymoma.)
Often the paraneoplastic symptoms appear before the cancer and can be brain/encephalitis symptoms or even dysautonomia. Sometimes the auto-antibodies knock out the cancer in a very early stage so it is never discovered and sometimes there is no cancer. But the auto-antibodies increase the risk and in my case where I am so symptomatic, we are going to try to knock them out either with plasmapheresis, IVIG or possibly immunosuppressants (but these are risky b/c they can actually increase your cancer risk.)
I've had some preliminary tests and am waiting to discuss with the docs but my lung cat scan from Oct 2015 (from a different hospital) was not as high resolution quality as I was told. Plus it was six months ago so we needed to do another one which I did last week. It showed two types of nodules in my lungs but they are tiny (3mm or under) and one of them correlates with mold exposure which I had for 2-3 years at a severe level. I will discussing with the lung doctor what they might mean but my understanding is that they are too small to identify beyond "non-specific" and we just watch and wait.
We also tested to make sure I do not have pulmonary hypertension or blood clots in my lungs and while I do not yet have 100% confirmation on this, it appears that I do not. But the two antibodies are affecting the neuromuscular junctions and the ability to push the calcium ion across the synapse. The calcium itself is there but it is being blocked by the auto-antibody which is attacking the calcium channel and it's functioning. The other antibody GAD65 is more vague and confusing to me but I think it is blocking the conversion of glutamate to GABA which can also affect my lung functioning.
Lastly I am trying a new med called pentoxifylline to see if it helps improve blood perfusion to my lungs. On my V/Q scan we think the mismatch is b/c blood is not getting to the apex/top of lungs due to dysautonomia/POTS and these antibodies. (All of this is paraphrased and interpreted by me who lacks any science background and nothing is a direct quote from my doctors.)
I had reached the point that ME/CFS was a wastebasket diagnosis for me and there were no more treatments to try. I feel so grateful that these antibodies have been identified, as well as the lung cancer risk that correlates with one of them so it can be monitored. And there is now a proposed treatment that could reduce or eliminate the antibodies and potentially improve my breathing and muscle weakness. I know it could not work, but am willing to take the risk as my QOL is so low.
Hope this helps someone out there and the timing was uncanny that someone started a thread on paraneoplastic syndromes as I was dealing with all of this!