Hello. I'm just a (bad) med student and I'm not qualified to make any diagnosis, but I think the clinical picture you have reported warrants further investigations and I wanted to share my thoughts while I was reading your post.

In the demographic of woman of child-bearing age the coexistence of more than one autoimmune diseases is not uncommon. Occasionally, there are even combinations of several of them [1]. As you've written, the manifestations you have reported may or may not be caused by one or more autoimmune diseases, but the ones that tipically keep autoimmune/rheumatologic origin in consideration even when labs are negative are the partial spinal fusion and the arthritis [3][2].

> According to every test they run on her, there appears to be nothing wrong

Does it? We have:

- clinical picture strongly suggesting some rheumatologic disesease: inflammation and rapid onset arthritis are typical, but DVT, random bleeding may also be linked.

- radiographic evidence of spinal fusion.

And that's exactly how (eg) Ankylosing Spondylitis has been diagnosed classically (i.e. when MRI was not an option) [4]. More generally speaking, as the name suggests, the diagnosis of most Seronegative Spondyloarthropathies is based more on clinical than laboratory criteria [3]. For how I understand it, ideally AS would be diagnosed before spinal fusion happens, but when it's present and there isn't a more likely explanation AS would be at the top of the differential diagnosis.

Another thing that came to my mind when reading DVT, bleeding, vision loss was that these are more typically seen together in of some kind of vasculitides, hence why I mentioned above an the possibiity of multiple autoimmune diseases, but these could also be explained by anything altering Virchow's triad.

> There's no explanation for the temporary blindness, the rapid onset arthritis, the partial spinal fusion, the diverticulitis, the random bleeding,

That sounds somewhat strange. While for temporary blindness, diverticulitis and DVT the cause may already be gone by the time the patient arrives at observation, at least for rapid onset arthritis, spinal fusion and random bleeding I think a diagnosis of the cause should be made.

The reason why rheumatologic diseases should be diagnosed is that if left untreated there will be periods of remission, when nothing happens, and periods of activity, when irreversible damage accumulates. Another reason to diagnose rheumatologic diseases is that they may themselves be manifestations of some other condition (e.g. rheumatologic paraneoplastic syndromes). We don't know if your wife actually has a disease, it may be not, but that's not a risk a doctor would leave to chance. It's just standard practice.

As I've already written I'm not a doctor, but if I may give you my advice anyway I would say your wife should go and see a rheumatologist.

> There's no one who either wants to or is qualified to look.

If I were in you, at this point I would go to some known research center with maybe a university department or ward.

[1] [Coexistence of Axial Spondyloarthritis, Systemic Lupus
Erythematosus, Sjögren’s Syndrome and Secondary
Antiphospholipid Syndrome: Case Report](https://dergipark.org.tr/en/download/article-file/1615538)

[2] [Approaching the Patient with "Joint Pain" - CRASH! Medical Review Series ](https://www.youtube.com/watch?v=sfKWNeAywak&t=195s)

[3] [Seronegative Spondyloarthropathies - CRASH! Medical Review Series](https://youtu.be/hvQkROf5rsQ?t=377)

[4] [Progression of Spinal Fusion in Ankylosing Spondylitis](https://clinicaltrials.gov/ct2/show/NCT00085995)