You know..years back I had a poodle that did that exact same thing...She could fly up those stairs so fast... 
 
 
But cry at the top to come back down... 
 
 
I would pick her up and put her about 5 steps down...with a leash on...guide her slowly down...
It was something I had to do a few times..and once her confidence built..she could fly down them! LOL 
