Preprint Beyond pain: Using Unsupervised Machine Learning to Identify Phenotypic Clusters of Small Fiber Neuropathy 2024 Murin et al

It's certainly interesting and raises many questions for me. Was there some biased selection of the participants? How common is a finding of SFN in people who would rate themselves as healthy? How many of the people in the Type 3 group would meet ME/CFS diagnostic criteria?

SFN has been raised as a comorbidity of ME/CFS for a while now. I'm not sure that we have any really good data on its prevalence though. It's too easy for the selection of participants to be biased.

Possibly, people who have some pins and needles, the occasional burning pains in their feet but are otherwise healthy might just ignore those symptoms, thinking 'everyone probably gets that'. I think that would have been the case for me. Whereas if someone is debilitated by fatigue/PEM/fatiguability, they might start assessing and reporting every symptom they have, in order to find a clue?

 

According to standard annual bloods my lipids have always been within normal, apart from a couple of borderline results over the years.

Plus a couple of times my fasting sugar levels have been borderline, but the follow up test for diabetes has been negative.

Only consistently abnormal standard lab result for me is alkaline phosphatase, which is always high (typically around 140-160, IIRC), and has been since at least my mid-20s.

 

Don't know if I have been tested for GGT levels. But I don't think there have been any liver function tests.

The high ALP was originally noted by the professor of immunology who diagnosed me with ME/CFS. Neither he nor any other clinician since has thought it something worth following up on, and I have asked about it a number of times. Main responses have been that it was too unspecific a finding to tell us much, particularly in the absence of other findings or symptoms, and that is was not so high as be a significant concern. The normal range is not well defined and can very quite a bit, and depending on which authority you read it can overlap with my range, and my understanding is that it is not considered worth following up on until it is above about 200, particularly in the absence of other signs or indicators. All complicated by having osteoarthritis, and also getting old (early 60s), both of which can be associated with raised ALP.

Will ask my doctor about GGT next visit.

 

Interestingly, one of the main findings of the DECODE genetic study is liver dysfunction (plus insulin resistance and low level inflammation), and liver problems are one of the main suspects for raised ALP levels.