FCEM2-0505

You evaluate a 4-year-old girl who has been diagnosed with diabetic ketoacidosis (DKA). She had initially improved after receiving fluids, but her condition has worsened in the past hour. She is now expressing discomfort due to a headache and is displaying irritability. She has started vomiting again, and the nursing staff has observed an increase in her blood pressure and a decrease in her heart rate.
What complication has developed?