My mother-in-law recently had her arm swell 3 times the normal size. Could this be from her previous stroke?

It sounds like congestive heart failure. Is she on Hospice? If you want this treated, I would call 911 and have her taken to the ER.

With the history of recurring UTIs it could be kidney failure. I certainly don't understand the blase attitude at rehab, what kind of staff are you talking to, aides or nurses and doctors?

She is acutally in the hospitals rehab.. so yeah Doctors and nurses. Awaiting cardiologists visit as he saw her yesterday, did not call us and said continue rehab. Up until her being moved into the hospital's rehab section care was excellent. So in answer, she's at the hospital so ER kinda redundant, trying to get her moved to acute care.

As she is in the care of medical professionals, i.e. physicians and nurses, I would not rush to judgement on the possible cause(s) of your MIL's edema. It may very likely be due to disuse and lack of vascular tone... the blood may not be circulating out of her peripheral limbs because of inactivity and decreased circulation. You might question the possibility of blood clots, however, I would suggest that it would be rather unlikely, given your MIL is experiencing this swelling in her left arm as well as in her legs. Congestive Heart Failure usually present with other ominous symptoms that would have been picked up on by her cardiologist. Kidney failure, too would present with additional symptoms that would likely have already been noted by staff who are attending her. It is not entirely unusual to see peripheral edema in folks post stroke. If she is not having difficulty breathing and her cardiologist isn't picking up any cardiac related symptoms, I would focus on increasing mobility of affected limbs, as well as elevating them above heart level when at rest and possibly employ the use of compression stockings to help your MIL's body with the task of pushing the blood out of her periphery and back to her heart where is can circulate appropriately.

Well it's 3 days later, arm and leg still swollen.. talked to doctors, nurses, ect. Yet another UTI..

I would suspect one of a few things -- kidney failure or vascular disease are two of the things. I hope you can find out what causes it soon.

Lymphedema, Perepheral Vascular Disease, Kidney and Heart Failure, can all cause swelling in the extremities, and also DVT. She definitely needs to be seen by a Cardiologist.
Is she laying on one side, and lot? Or, hanging her legs a lot, while sitting in a wheelchair or other chair?

Are you Certain, she hasn't had a fall?

A DVT needs to be ruled out! And If/When it is, then there are massage techniques that can help with the swelling, in addition to wrapping the affected limbs from the hand or foot upwards, loosely, BUT SHE MUST BE SEEN BY THE CARDIOLOGIST FIRST, before any of these type things should be tried!!!

Is she Short of Breath? Is there any redness, suggestive of Vasculitis, DVT, and cellulitis? Is there any pain along with the symptoms in the affected extremities? Has she had a Headache, suggesting a stroke, or TIA, these questions all need to be asked of the Cardiologist, and normally, they do ultrasound type tests, to rule out a blockage!
I don't know the age of you MIL, or what her DNR status is, or other physical symptoms, life expectancy and such, but if you are wanting her to have the very best chance at living beyond such symptoms, I would be Very Persistent in getting her Acute Care, as in 911!

She is being seen by a cardiologist, she is in the hospital (rehab) still. She had the 4th stroke Dec 17th 2016, and is having cat scans done weekly since and yes they have ultrasounded arm, chest and leg.

I would want a vascular surgeon called in. If they have not found the cause, they have not done the right testing. Unresolved vasculitis can lead to more strokes.

Well after extensive stay at the hospital rehab she is home as of last thursday.......Rehab took her off all her antipsycotics, most of her BP meds, her potassium, water pills and tried to call in IV wafararin for home use.. Sent her home with VRE no antibiotics, so gloves and gown for all care when we are handling her. To say the least not real thrilled with the rehab. She's sundowning starting at 1pm now, left side pretty much gone strength wise, 3 nurse visits just since friday they are suggesting palative care now.

It sounds like she is already on a hospice protocol, that the VRE (vancomycin resistant enterococci) has taken over. You are looking at a short time frame at home. Yes gloves and gowns and maybe think about an exhaust fan in her room to keep the airspace negative. UV sanitizing lights at the doorway. Protect yourself. Protect visitors.

Yes, agree with pamstegma, sounds like a hospice protocol especially if they have stopped all her medications. Is that what you have been told, as you alluded to "they " have suggested palliative care. Ask her doctor if he ordered Hospice or read the paperwork she was sent home with.
Try to keep her toileting confined to one bathroom if you/she has access to one. VRE has certain precautions. Make sure you wear gloves, wash your hands and have plenty of antibacterial gel around in pumps for easy use for infection control. Bleach is required to clean surfaces as well.
Good luck to you, my dear.

No the Doctor did not order hospice, the nurses from home health care and her primary doctor have suggested pallative care. The rehab stopped her meds, her primary is trying to get them sorted and correct again. Basically rehab dropped the ball. We now have her set up in the living room, 1/2 the room devoted to her, other half for visitors. On another note she's alot stronger than we thought woke up to her naked, wet from head to toes, legs thru bed rails, both legs ( remember left side does not work) screaming she was in pain.... gloved and gowned up, washed her in bed, changed her, lifted her with the lift cleaned the bed, replaced bedding she was asleep before I had her lowered.

Wow, you know how to handle the Hoyer lift, that is huge! Kudos!