Very interesting to hear your experiences. I have long suspected some sort of autoimmune condition (specifically undifferentiated spondyloarthropathy) resultin

Very interesting to hear your experiences. I have long suspected some sort of autoimmune condition (specifically undifferentiated spondyloarthropathy) resulting in me having similar symptoms. My first symptom was tendonitis, but I was 22 back then (37 now) and very physically active so doctors just attributed it to overuse. Then both elbows tricep tendons developed enthesis and ossified at the insertion point. I have similar enthesis in basically every major joint now, and they still think it's from the exercise. I did push my limits with weights when younger but it's difficult to imagine that being the cause of all the issues I've had. Similar to you, CRP tests were fine and bloodwork was all good, however they did find I was positive for the HLA-B27 antigen which is a known marker for autoimmune conditions and only present in about 5% of the population, but present in 90-95% of those with spondylitis, so there's one red flag. The issue is as you mention, there is no definitive diagnoses until they see joint damage on X-ray, and by then you've missed years of potential intervening treatment. Eventually I developed brain fog like you describe, but it was gradual and difficult to tell if the symptoms were related. It's not always debilitating but I'd say 4/5 days I'm foggy to varying degree, and then one day where I'm about 3x sharper. I've learned to just ride the productivity wave those days and do mundane stuff other days. I thought it may be sleep related, and although getting more sleep does seem to give me a higher probability of a "good" day, it's not a panacea. There are days where even after 10 hours I'm still foggy, and I can tell immediately upon waking up how the day will go. While I'm sympathetic to those who say googling your way to diagnoses can be harmful (and no doubt it may frustrate some doctors), I don't entirely agree. You have to live with your body and mind 24/7, and you have one and only one patient to care for - yourself. You will always be more motivated to find the answer than your doctor. A doctor cannot read your mind or feel your pain, and simply pattern matching symptoms is something anybody can do. It can never hurt IMO to go into the discussion informed and ask pointed questions. The medical field is an evolving science, they don't have all the answers, they don't even have most of the answers.