What Causes Severe And Violent Changes In A Person After A Head Injury?

MY MOTHER FELL LAST MONDAY HITTING HER HEAD AND BREAKING HER SHOULDER, SHE WAS ADMITTED TO THE HOSPITAL WEDNESDAY AND HAD SOME CONFUSION. SATURDAY EVENING SHE MENTALLY CHANGED SO BADLY THAT SHE WAS VIOLENT AND NOT MAKING ANY SENSE AND TRYING TO LEAVE THE HOSPITAL. TODAY, THREE DAYS LATER SHE SEEMED BACK TO NORMAL AGAIN WHEN I VISITED HER AND THEN AGAIN TONIGHT SHE SUDDENLY CHANGED AND BECAME VIOLENT AGAIN. THIS IS OUT OF CHARACTER FOR HER. THEY DID TWO CAT SCANS SO FAR THAT SHOW NOTHING, BUT AN MRI WAS DONE TODAY AND I AM STILL WAITING TO HEAR THE RESULTS. DOES THIS SOUND LIKE A HEAD BLEED? THEY SAID ON SATURDAY THAT IT WAS PROBABLY A REACTION TO HER MEDICATION SO STOPPED THIS.