Most parents don't realize that not getting enough food can be the cause of unexplained vomiting in the middle of the night or first thing in the morning.

Where there is no fever, stomach flu, or any other common cause of vomiting in younger children, vomiting is often caused by low blood sugar. Most typically, this happens to children between 8 months and 4.5 to 5 years of age.

The official diagnosis for this scenario is ketotic hypoglycemia. Vomiting induced by ketotic hypoglycemia usually happens in the middle of the night or first thing in the morning, and typically when there's been a longer-than-normal stretch of not eating - missing dinner is a common cause for those who are predisposed to this.

The child will typically feel some nausea and/or abdominal discomfort just prior to vomiting, and will usually be subdued for about a half hour after vomiting, but will otherwise appear normal.

Vomiting caused by ketotic hypoglycemia is often misdiagnosed as the stomach flu. The distinguishing feature of ketotic hypoglycemia is that the child quickly returns to normal; if vomiting occurs in the middle of the night, after a short period of malaise, the child will typically sleep comfortably for the rest of the night; if vomiting occurs first thing in the morning, within about 30 minutes, he or she will be ready to eat and go about everyday activities.

Vomitus is typically bubbly and tinged with a bit of yellow color - this is distinctly different from vomitus that accompanies the stomach flu, which usually includes incompletely digested food.

Normally during night-time sleep, the body uses blood glucose and some stores of glycogen in the muscles and/or liver to generate energy needed to carry out basic metabolic activities. Ketotic hypoglycemia tends to occur in young children who either miss dinner or eat a smaller-than-usual dinner and are in a rapid phase of growth where their need for fuel is greater than what a small meal in the late afternoon or early evening plus glycogen stores in the muscles and liver can provide; this is why vomiting from ketotic hypoglycemia typically only occurs in children who have a leaner-than-average build.

How to Prevent Vomiting Caused by Ketotic Hypoglycemia

Where ketotic hypoglycemia is identified as the cause of a child vomiting at night or in the morning, treatment is simple: Just ensure that your child has a healthy bedtime snack to avoid having his or her body go more than 10 hours without food intake.

Differential Diagnoses

There are many causes of hypoglycemia, as well as causes of vomiting at night that are not related to hypoglycemia, so in cases where it's not obvious that lack of food intake in the evening is causing ketotic hypoglycemia-induced vomiting, it's prudent to have your physician fully evaluate the situation to rule out other potential causes.

Stomach flu, food "poisoning," severe coughing, a bladder infection (will be accompanied by a fever), and some type of intestinal obstruction are the main differentials to rule out.

Almost all children that experience vomiting caused by ketotic hypoglycemia grow out of it as their body mass increases with age and their ability to fast during bedtime sleep improves.

Please consider sharing this information with parents, grandparents, and elementary school teachers in your life. Being aware of this potential cause of vomiting in younger children makes it natural to understand that having them miss dinner isn't a good choice in punishment for misbehavior - it's wise to have other effective consequences ready in mind where some form of discipline is indicated, as vomiting is always best avoided for its negative effects on overall health.