The above article explains fully. Essentially I'm in the wrong forum; Undifferentiated Inflammatory Arthritis which, is my diagnosis, is not the same as Seronegative RA, RD PsA etc. Discussions here have been about not knowing what kind of Inflammatory arthritis I have when in reality it hasn't fully developed and may even 'spontaneously' disappear. I was right that monitoring should be with more ultrasound scans but I think it unlikely with NHS. The purpose of putting me on mtx is to see what happens 😟😟.
I spoke yestrrday with GP and rheum. nurse who explained a few things. The scan showed synovial inflammation consistent with inflammatory arthritis, stage 1. I've never shown Inflammation in blood tests. I do also however have osteoarthritis type damage in all the joints I've ever had xrayed. That's a lot of joints. The mri on my neck showed some sort of damage or 'thickening ' of the tendons. I have antiphospholipid antibodies commonly found in the blood of RA patients but especially lupus. I also have Primary Raynauds which can be a sign other autoimmune diseases to come, years later. Confusingly Secondary Raynauds is also a very common symptom of RA, Systemic Scleroderma and Lupus. I'm not really sure which I have though because it started when I was 16 and pregnant. (Yes, I know, too young) It only ever happened when I was pregnant: in my nipples! Then decades later when I first had the huge puffy knee for no apparent reason and the same, with bruising in my elbows, I suddenly started to get Raynaud's in my fingers. Over the past 5 years it's spread to my feet and sometimes ears too and attacks can last for hours.
Putting that all together it's clear (or not) that I have a nice concoction of autoimmune diseases and DMARDs are the way all of these things are tackled initially with the hope that the arthritis symptoms are halted and permanent damage reduced.
The nurse was brilliant. She listened especially about my migraine/cluster headache concerns. We talked through all symptoms, my concerns and came to agreement that as my chest xray was clear she would send me the prescription for mtx , (she 'counselled' me about the drug too) but that I could hold off taking it until my phone appointment on 25th.