The typical patient with ketotic hypoglycemia is a "toddler", a young child between the ages of 10 months and 4 years. Episodes nearly always occur in the morning after an overnight fast, often longer than usual. Symptoms include those of neuroglycopenia, ketosis, or both. The neuroglycopenic symptoms usually include lethargy and malaise, but may include unresponsiveness or seizures. The principal symptoms of ketosis are anorexia, abdominal discomfort, and nausea, sometimes progressing to vomiting.
If severe, parents usually take the child to a local emergency department, where blood is drawn. The glucose is usually found to be between 35 and 60 mg/dl (1.8-3.1 mMol/L). The total CO2 is usually somewhat low as well, (14-19 mMol/L is typical), and if urine is obtained, high levels of ketones are discovered. Ketones can also be measured in the blood at the bedside (Medisense glucometer). Other routine tests are normal. If given intravenous fluids with saline and dextrose, the child improves dramatically and is usually restored to normal health within a few hours.
A first episode is usually attributed to a "viral infection" or acute gastroenteritis. However, in most of these children one or more additional episodes recur over next few years and become immediately recognizable to the parents. In mild cases, carbohydrates and a few hours of sleep will be enough to end the symptoms.
Precipitating factors, conditions that trigger an episode, may include extended fasting (e.g., missing supper the night before), a low carbohydrate intake the previous day (e.g., a hot dog without a bun), or a stress such as a viral infection. Most children affected by ketotic hypoglycemia have a slender build, many with a weight percentile below height percentile, though without other evidence of malnutrition. Overweight children are rarely affected.
I think that the above information fits KayTar pretty well. Her episodes started in toddlerhood, they frequently occur when she goes too long between feedings or during illness, she is extremely lethargic and unresponsive during them. She has landed in the ER many times with very low glucose numbers even though she isn't clinically dry or dehydrated. I think the underlying mechanism of her episodes might just be ketotic hypoglycemia, which triggers migraine activity causing the light sensitivity and pain that sometimes coincides with them. I think this has been overlooked because we have always focused intensely on the neurological symptoms. The hypoglycemia has often been excused because she has been vomiting from the episodes or from the illness she is sick with, but lately it has become obvious that her numbers are plummeting faster and more dramatically than they should with only a minor disturbance.
To my knowledge, we've never tested her urine for ketones during an episode or at times when she has been hypoglycemic, so that remains to be seen, but I do know that her CO2 has been low during some of her hypoglycemic episodes, too. The treatment for this condition is frequent small high carbohydrate, high protein meals...basically what we have been doing for her since getting the g-tube, and surprise! The episodes have all but disappeared. Her recent "energy crises" are often fixed with Pediasure and sleep, but when she gets sick or starts vomiting, things get a little dicier and sometimes she needs IV fluids. Anyway, it is a THEORY...and nothing more at this point. However if this isn't it, I really feel like it is at least in the right zip code now. The two really great things about this diagnosis, if it were the correct one, are that we could test her urine for ketones during illnesses and correct the errors before it ever progressed to hypoglycemia AND children outgrow it by age 10 usually.
I emailed her pediatrician about it, of course. We'll see what she thinks of it and go from there!