Over 550 illnesses....Are these to be learned?

Come on, only 550? Surely there are more diseases than that once you bring in all the freaky genetic mutations.

And NO. I don't know what some of those things are, and I'm a Peds nurse practitioner (and a pediatric nursing instructor)

The best way for me to learn is when I have something to 'hang' my knowledge on.
And what I did that really helped me was to look everything up that I came into contact
with. I worked summers and vacations at a children's hospital when I was in nursing school
and used to read charts during free time. I would study my patients' conditions and if something
rare came along, I always tried to learn about it. After I became an RN, I still had a ton of learning
to do, but this was the best way for me, as I was able to remember real people and that helped me
to remember diseases and conditions. If you don't have much exposure to real children, as I did, read online articles, even on this website and look up and learn about things you don't know.
As a previous poster said, 'one bite at a time'. Over time, you will learn so very much. And its fun!