In Season 2, Episode 22, "Shades of Gray", Dr. Pulaski pushed Deanna Troi's hand away from Riker when she was trying to give him a final treatment to rid his body of the infection from a vine that had infected him? Was this the reason why the character left the show?
It appeared so quickly so I looked at it again and that is what I saw. It appeared to be an out of place action by Diana Muldaur. When I watched the next episode, Pulaski was no longer on ST:TNG and Dr. Beverly Crusher was in the next and following episodes from then on.