Ketones are Generally Not Your Friends (Especially in Diabetes)
Let's test your knowledge: What are ketones?
- Large amounts of sugar in the urine
- Chemicals made when the body burns fat
- Large amounts of protein in the urine
- Small amounts of blood in the urine
As part of continuing education for our families, we developed a "ketone quiz." This quiz is the first of multiple "quizzes" that we will be giving our practice over the next few years to access our patient's knowledge about different diabetes related concepts. The quiz was given to all of our patients (type 1, type 2, etc.) who are seen in all of our locations. It was given to newly diagnosed patients who recently attended "Survival Skills" and "Concepts Class" as well as those with long-standing diabetes.
The results: The most popular answers were the following:
A. Large amounts of sugar in the urine (most popular) and
C. Large amounts of protein in the urine (second most popular).
More than 90 percent of our patients provided incorrect answers. It did not matter if their hb A1c was 6.5 or 10 percent, most patients (and family helpers) chose A. In fact, one of the more astounding findings was that children and adolescents with well-controlled diabetes knew less about ketone physiology because of the fact that they have never had them! People who have had episodes of ketosis were a bit more familiar with the ketone quiz due to real-life experience. What was the take home lesson? We learned that it was necessary to provide important information in a mini-refresher format! Adult learners tend to learn what they need to know now. If they are not confronted with an immediate problem, the information is less important and perhaps stored for future use and forgotten.
The correct answer... B: ketones are chemicals made when the body burns fat.
Let's review one of my favorite biochemistry pathways: aerobic metabolism (and more specifically glycolysis and the TCA cycle). For those who wonder why doctors choose their specific specialties... I have been entranced with this pathway since taking Advanced Biology in high school. In medical school biochemistry, we reviewed this important pathway and an endocrinologist said that this elegant pathway was blocked IF the insulin hormone was not available. WHAT? If insulin was not there to facilitate glucose into the cells, then this beautiful pathway with the circular TCA cycle and ATP production was non-functional? Yes, he replied. And thus began my interest in insulin-dependant diabetes.
If insulin is not available in suitable amounts, glucose cannot enter the cells and glycolysis is not available to provide energy through the usual pathway of glucose metabolism. Instead the pathway goes in the reverse direction and ketones are formed. Ketones are produced when fat is the substrate used for energy due to the lack of glucose in the cells. Fat is metabolized to fatty acids and triglycerides. The fatty acids are then metabolized and ketones develop.
"Ketones are generally not your friends" (especially in diabetes). There are, of course, exceptions to this rule in people without diabetes that are on specific diets to lose weight (Atkins) or the ketogenic diet in metabolic disorders. The ketones in the Atkins diet are used to monitor fat breakdown. In people with diabetes, ketones indicate fat breakdown. In the presence of high blood sugars, ketones are generally produced when there is not enough insulin to transport glucose into the cells for energy. Increased ketone production leads to increased acid in the blood, which then may lead to diabetic ketoacidosis. In the presence of low blood sugars (or after sleeping overnight), there may be little glucose available due to lack of eating, and ketones may develop secondary to "starvation ketosis." The treatment of starvation ketosis is to give small amounts of glucose and getting the blood sugar up and then administering insulin as usual. The exception is if someone is ill--then the diabetes team must be called.
The treatment of ketones with high blood sugars is urgent to prevent DKA. We ask our families to call the diabetes team immediately to try to fix the problem at home before a visit to the hospital becomes imminent. Increasing fluids and aggressive insulin administration is necessary to clear ketones. If vomiting is persistent and it becomes impossible to keep down fluids, a trip to the hospital will become necessary to administer IV saline. Generally, if a family calls us immediately, in many cases we can work aggressively to avoid a hospitalization....but not always.
What are the most common causes of ketones with diabetes?
1. Omission of insulin either accidentally or knowingly
2. Viral or other illnesses in which there is not enough insulin to transport glucose to the cells
3. "Starvation ketosis" as noted above
4. Severe hypertrophy at the insulin injection sites (and insulin not absorbed)
5. Expired or denatured insulin (non-functional)
6. Insulin pump malfunction or clogged tubing/site issues
7. Other less common reasons ...
Lastly, ketones are not only relegated to those with type 1 diabetes. There are increasing numbers of children/adolescents with type 2 diabetes that may present at diagnosis with ketones. Although, please keep in mind that ketone production in Type 2 diabetes is NOT a common occurrence.
I hope that I have been successful in providing a short "primer" in regard to ketones and diabetes. Please feel free to submit further questions in the comments section and I would be happy to answer to the best of my knowledge.