Hello, and welcome to KA.
You might check out this article on Psoriatic Arthritis:
EMedicine Sausage digits don't happen too frequently in patients with AS, but they do in patients with Psoriatic or Undifferentiated Spondy. That and the facts that you have Psoriasis and the Achilles involvement is prevalent made me look into it. Also, rib pain happens often with PsA, as does SI involvement. Psoriatic Arthritis (PsA) is one of the Spondies, by the way, and definitely related to AS, so they do get mistaken for one another.
My sweetie has Psoriatic. He has Psoriasis, sausage digits with nail involvement, his wrists are badly affected and one is almost fused, and his Achilles are really bad (horrible rupture of the left one 2 years ago that took ages for him to recover from). He has some back pain, but not like mine with AS. About 20 years ago a doctor diagnosed him with AS, but he was never treated for it. It was only a couple of years ago that he was definitively diagnosed with Psoriatic and given proper treatment. He's doing much better now, although his wrists poop out on him very easily.
When it comes to your ribs fusing, you need to start doing breathing exercises. The lung expansion will help combat the ribs fusing. Take a long towel and wrap it around your torso, just at the diaghram. Take the left end in the right hand and the right end in the left hand and tighten the towel around yourself. Inhale as deeply as you can, holding the towel tightly, then as you exhale, tighten the towel further. This will provide resistance and work the muscles in that area. Do this ten times every day.
I found that I didn't get a good night's sleep until I got a memory foam mattress, but we're all different. The same goes for prognosis. We are all different and our bodies respond differently to various treatments, as well as to the disease. Learn to listen to your body and the messages it is sending you. Do your research to learn about various treatment options and make your decisions from the point of view of knowledge, not fear. The more you understand, the more effectively you can work with your healthcare team.
I'm not saying you actually do have Psoriatic, by the way. The longer I live with AS, the more I realize that it is completely different in every patient. That said, it's worth looking into to ensure you get the best treatment possible for your condition. My sweetie was put on Enbrel for his Psoriatic and it not only helped his pain levels and wrists, but his Psoriasis cleared up and so did the sausage digits, as did his toenails. I'm on Enbrel for my AS and it helps, not as much as Remicade did but enough that it's definitely worth taking. The treatments are often similar among the Spondies, but certain meds are better for one than for another.
Just a few thoughts for you to gnaw on.
Hugs,
