Does anyone know how a US-trained

I don't think it will be an easy task for you.  There are a lot of highly qualified doctors.  My husband graduated from the U. of Pisa Faculty of Veterinary Medicine and at the time we were only US citizens.  It would have been quite difficult for him to practice there at that point.  We do know of a few people who married an Italian and eventually were able to work there.  We now have dual citizenship and my husband if fully quallified to work in Italy. I would google for information as well as contact one of the medical schools to see what you can find out.  I did a very quick search and found this article which has some suggestions of whom to contact:The website is http://www.bleedle.net/italydoctors/  

You will most likely need to get their education. It may take a couple more years to do this. But don't worry - it's never too late to learn. I decided that I still want to get a higher education, so now with the help of https://plainmath.net/secondary/calculus-and-analysis/calculus-2/differential-equations I am actively preparing for the exam in mathematics - it will be the most difficult. I practice a lot solving differential equations problems, integrals and other heavy equations and problems. I want to prove to myself that I'm not stupid, and I can easily deal with this exam!