The horrible realization is most people are going to get a serious illness or need to go to the hospital at some point in their life. The worst part is your children will want to know what is going on. If you are a parent and you are sick, you will want to prepare your child to some degree to let them know what is going on and why you are not at home.
Ask yourself how much your child will understand. Should you tell them where you are going? Should you send them to a "sleepover" and not tell them anything? Will telling your child details help them or scare them? What will your child understand the most? Should you let your child visit you in the hospital?
Children are resilient creatures, but there is no reason to truamatize them. If you are going in the hospital for a few days for non-life threatening illness or disease let your child know you are going to be gone for a few days and when you will be back and whether or not your child can see you. Your child will know you are gone so it is best if you let them know you are leaving ahead of time.
Tell your child only what he or she will understand. You know your child the best. Explain to your child what is going on so they will understand. Do not go into great detail unless your child asks. Answer all of your child's questions. Tell them who they will be staying with or who is staying with them and how much fun they will have. Be sure to let them know you love them and you will miss them and let them know whether or not they will be allowed to visit. If your child isn't allowed to visit do not tell them that. Just tell them you will see them when you get back.
It is always best to explain what is going to happen. When children know what is going on ahead of time they cope better with what is happening. Only you know what your child will understand. Always talk to them on their level.