What Symptoms Indicate Brain Infection Or Swelling In Children?

I have a three yr old grand daughter whom has all these symptoms but three and she is now in a childrens hospital and they aresaying brain infection or a swelling. but we have a sample in toxology of vomit that smells like cleaning solutions and have mentioned for them to check the stomache but they seem to think all is well how can we find out about that sample and if this could be the cause of her health issue as we speak