Hello. I'm not a medical professional, just the parent of a kid with diabetes. Ketones must be treated with insulin. Water alone will not get rid of them. If the MD did not advise to get insulin to bring down the ketones, the MD is misinformed about diabetes, and an endocrinologist should be consulted. There is a specific formula that is used to determine just how much insulin to give, and how often to give it, and that needs to happen ASAP.
It sounds as if the MD is thinking that the vomiting is due to virus (hence, only give water to avoid dehydration) and is not taking into consideration the dangers of ketones in a type 1 diabetic. I, too, would question the advice given by the doctor. It is possible that the child has high glucose levels because of a virus, but still the ketones should be watched carefully and insulin increased given appropriately to lower those 300 levels to normal, sick or no.
Something needs to be done before you have to call 911 to treat diabetic ketoacidosis. I have been hospitalized for this 7 different times, each time being admitted to the icu. As soon as the vomitting start, I head straight for the emergency room because I have done this a few times and I know when its starting to get bad. I start to fell like I cant breathe. then I start vomitting. I also agree that the doctor doesnt seem to know what hes doing. I will provide the Technical termonolgy and definition for dka at the end of this. Please consult with and endocronologist. I hope I spelled that right.
 Symptoms and Signs
Sluggish, extreme tiredness.
Fruity smell to breath/compare to nail polish remover, similar to peardrops.
Extreme thirst, despite large fluid intake.
Oral Thrush may be present, or/ yeast infections that fail to go away, this is because the normal fungal/flora present in oral cavity/cervix in women, the balance is upset and bacterial began to feast on the high sugar from urine output/ dry mouth from extreme thirst.
Agitation / Irritation / Aggression / Confusion Diabetic ketoacidosis (DKA) is a life-threatening complication in patients with untreated diabetes mellitus (chronic high blood sugar or hyperglycemia). Near complete deficiency of insulin and elevated levels of certain stress hormones combine to cause DKA. DKA is more common among Type I diabetics, but may also occur in Type II diabetics generally when physiologically stressed, such as during an infection. Patients with new, undiagnosed Type I diabetes frequently present to hospitals with DKA. DKA can also occur in a known diabetic who fails to take prescribed insulin. DKA was a major cause of death in Type I diabetics before insulin injections were available; untreated DKA has a high mortality rate. These were taken from wikipedia.
Wonderful comments by all. I want to add one more thing: dka is much more dangerous in children than in adults, and the mortality rate of children with untreated dka is still fairly high after all these years. Moderate ketones that stay that way should be treated, and vomitting should not be assumed to be viral in a diabetic child if ketones are present. It can be a matter of life or death for a youngster much quicker than for an adult.