It actually seems a bit funny to me that the President of the United States, who very likely has medical workers on standby who give routine checkups without him having to leave the White House (and I would guess they also have equipment such as Ultrasound and X-ray machines on site) would have to go to a hospital as part of a "routine healthcare visit".
He's clearly got something chronic that they can't treat at the Whitehouse, which is saying something. Likely, what technarch noted is on the right path: they need an MRI or CT scanner, with CT being unlikely since they're a lot less expensive to install and maintain than a MRI (no liquid helium storage for a CT). The best two theories i've seen are congestive heart failure, with frequent need for IVs to deal with that or failing kidneys, and the second option is that he's getting IV drugs for dementia and they're doing imaging on his brain to track the efficacy of those drugs.
Leqembi or donanemab seems likely, since both need to have an MRI handy to make sure they aren't causing certain side effects, like brain bleeds and swelling. It explains the cadence of bruising we have seen, and they're only intended for early dementia patients. His cognative decline would also align with this treatment.
Congestive heart failure feels likely, too, given his cankles and waddle getting worse and his frequent "puffy" appearance. And it could be both, god willing.
Personally, I'm guessing he goes this winter. It's so hard to avoid picking up various viruses with the number of people he's around, and if he is dealing with CHF then the likelihood of it getting severe goes way up. I've had many otherwise fairly health family members get their asses abosolutely kicked by nasty colds that progress. My mom is 16 years younger than Trump and has COPD as well as having a stent in her heart, and her Dr. basically told her a case of pneumonia could easily escalate to her going into the hospital. I know they have ample medical care for the POTUS, but still, the signs are there.
