My 18-month-old baby is vomiting after every meal for the past four days. Why?

Hi doctor,

My 18-month-old child has been vomiting on and off after eating for a few days. It started Sunday night after dinner. Then she vomited after nearly every meal Monday and Tuesday. Wednesday, she was dehydrated, so we took her to the emergency department. She had low blood sugar and high ketones. She began to eat and drink and keep it down (only one small vomit that morning). The next day (today), she vomited once in the morning after drinking (I think too much, and stuffing a piece of pancake in her mouth and choking on it). She has been eating bits and pieces and drinking throughout the day with no more vomit (fingers crossed we have reached the end of it). She passed stool once during her illness, on Tuesday (two days ago). The current GP is worried about bowel obstruction, so we are giving her a mild laxative to bring on the next poop, hopefully. Blood glucose and ketones were tested. Glucose was 2.8 in the hospital, and ketones were 5.7. both have improved, and we were discharged last night.

Is this likely some virus or stomach bug? Even though she has had no diarrhea. Is it normal or common to have a virus with just vomiting? She does not seem to be in pain, is playing happily today, a bit tired. The last time she had gastro (first time), she had diarrhea and vomiting. The vomiting also lasted three days during this bout. That was six to seven weeks ago. Kindly give your opinion.

Hi doctor,

Thank you.

She has once passed stool, and she does not appear to be in any pain. She is still quite happy. However, she vomited after eating again this evening (the last one was this morning around 8:00 AM). She wanted to eat more after vomiting, so she still has an appetite. I did think maybe the vomiting should have stopped by now. It is day five. Is it normal for the vomiting to be persisting for this long? On the internet, it mentions 24 hours, but we are way past that. We are wondering whether we need to take her back to the emergency room or whether we need to wait it out. Kindly give your opinion.