Could The Drop Of Hematocrit Levels In A Child Be Due To Internal Bleeding?

My granddaughter bumped her head on an indoor slide at the gym....she seemed fine...nothing out of ordinary not even a bump...not throwing up, eating fine, playing fine, sleeping fine.....she went to doctors a week later and they noticed her hematocrit had dropped very low....it was low few months ago but now had dropped more.....could she have internal bleeding in her head from that bump even though seemingly no signs of anything going on