I'm not nearly as educated as the others here, so I might not have any really useful info. But I do have Sjogren's like you, so I wanted to mention some of the symptoms I've had that were similar.

In May 2003, I woke up one day to find my left foot swollen. I thought it was odd but just went to work as usual. The next day, though, both feet were swollen, and the swelling on the left side spread all the way to the knee in just a few hours.

I went to the emergency room, which is something I almost never do. My bloodwork was normal, as was a lung x-ray, and an ultrasound of my left leg. I was told it was the Sjogren's and was put on prednisone for a week, which helped until the the med wore off.

I have had problems with edema ever since. It is worse in the heat, but I get it in the winter too if I go too long without elevating my feet. I'm thinking it may be caused by mild vasculitis as I have petechia on my lower legs, face and upper arms.

It could be something other than the Sjogren's that's causing your swelling, of course, but I thought I'd mention it just in case your tests don't give you any answers.

What I do about the water: I got a half-gallon water bottle, one that has a long strap so I can carry it on my shoulder. I cart that from room to room with me and never leave the house without it. I try to make sure I drink the entire contents each day, refilling it at bedtime so when I wake up in the middle of the night with my tongue all cracked and dry, I can take a swig and go back to sleep.

Please let us know what you find out. I'm most curious if your symptoms are caused by autoimmune disease or something else.

fanfaire