What Are Ketones in Urine?
Published January 22, 2018 by David Spero, BSN, R
What are ketones? How do they get into your urine, and why should you care?
Ketones are everywhere in nature and in our bodies. We couldn’t live without them. Proteins and fats are largely made of them.
Our bodies normally run on glucose we get from food. When bodies don’t have glucose because of starvation or illness or can’t use glucose because of a lack of insulin, they start burning fat for energy. The fat breaks down into ketones, with these ketones pouring into the blood and some passing into the urine. This release of ketones into the urine is called “ketonuria” (pronounced KEY-tone-ER-ee-uh).
The buildup of ketones in the body is called “ketosis” (key-TOE-sis.) If your glucose is close to normal and you are well-hydrated, ketosis is no problem. Many low-carb diets create ketosis on purpose, as it can be an indicator of fat burning and weight loss.
However, ketones are acids. If you have too many ketones, they can make your blood too acidic. This can lead to a very dangerous and often life-threatening situation called diabetic ketoacidosis (DKA).
Remember, ketones appear in blood and urine because the body is breaking down fats for energy. It should only happen if glucose is low. If you have above-normal glucose and also have ketones in the urine, something is seriously wrong.
Symptoms of ketoacidosis
Most of the classic symptoms of diabetes are symptoms of ketoacidosis:
• Excessive thirst
• Dry mouth
• Frequent urination
• Fruity-smelling breath (ketones have a fruity smell)
Later, more dangerous symptoms include:
• Nausea and vomiting
• Abdominal pain
• Weakness and fatigue
• Shortness of breath
What causes ketonuria in diabetes?
In people with Type 1, ketonuria means they’re not getting enough insulin. Insulin keeps fat from breaking down, so ketones should not form if you’re taking enough insulin.
People with Type 2 can develop ketonuria if they have severe infections, major trauma, or stress. These conditions raise the need for insulin. People can have internal infections without being aware of them.
A study in Chicago evaluated 138 consecutive admissions for DKA at a large academic center. They found that 21.7 percent of those admitted had Type 2 diabetes. Almost half of the people admitted had an identifiable infection. In a Swedish study, 32 percent of DKA cases were people with Type 2.
A subset of people with Type 2 have what is called ketosis-prone diabetes or KPD. In KPD, the pancreas occasionally shuts down insulin production for unknown reasons, making a person subject to DKA.
In Type 1, a common cause of ketonuria is insulin pump failure. A person thinks they are getting insulin, but they’re not. The line has been blocked or the machine is malfunctioning. Without insulin, fat starts breaking down into ketones.
The University of California at San Francisco diabetes education program warns, “There is a higher risk for developing ketones on pump therapy. This is because long-acting insulins are not used, and rapid-acting insulin is delivered in extremely small amounts. If this basal insulin delivery is interrupted for more than an hour, check your blood sugar and ketones.”
Sickness raises the risk of DKA in all people with diabetes, but especially Type 1. Illness often tends to raise the need for insulin but frequently decreases a person’s appetite, resulting in less food intake than usual. Because they’re eating less, some people may decrease their insulin dosages, when they really may need increased amounts of insulin.
When to check urine for ketones
Urine ketone test strips are quite cheap, and you should always have some available. (The Nova Max Plus meter can test the blood for ketones.) Test whenever:
• There is an unexplained rise in your blood sugar, or you have a blood sugar level of more than 250 mg/dl (13.9 mmol/l) for two tests in a row;
• You have symptoms of nausea, vomiting, confusion, or severe fatigue;
• You have any symptoms of ketoacidosis such as increased thirst and urination, stomachache, or dry mouth;
• If you have a flu, infection, or injury;
• When you’re planning to exercise, but your blood sugar is over 250 mg/dl.
• If you are pregnant, check for ketones each morning before breakfast or whenever your glucose goes over 250 mg/dl.
If you have ketones in your urine (or blood):
• Have a sick-day care plan worked out with your doctor. Keep in touch with your health-care providers if you have ketonuria and high glucose. You may need to be checked for an underlying cause or may require additional insulin to bring blood glucose levels down.
• Call your doctor if you’re vomiting. Vomiting can speed up DKA.
• Drink plenty of water (or other calorie-free fluids) to flush the ketones out of your body.
• Monitor blood sugar levels and ketones every three to four hours.
• Avoid exercising when you have ketones and your blood glucose is above 250 mg/dl. This is because when you do not have sufficient insulin, the increased energy demands of exercise will burn fat, producing additional ketones.
• If you are using an insulin pump and have ketones, inject some insulin as needed depending on your blood glucose level and change the pump infusion set and reservoir.
Want to learn more about ketones and diabetes? Read “Ketones: Clearing Up the Confusion” and “Getting to Know Ketones,”then try your hand at the quiz “How Much Do You Know About Ketones?”