Can a stroke in a child cause an intelligence deficit without a physical deficit?

Possible: That is possible, a child's brain is very plastic, ie able to recover function better than an adult. If the stroke was not large and not in an eloquent area of the brain (language, speech etc), the recovery of cognitive skills should be very good, especially if the child is very young. In fact, motor skills also make good recovery with rehab and ongoing play and encouragement. It's size & location.