What are ketones?

If your body does not have enough insulin, it cannot use glucose from your blood as energy and eventually it will begin to burn fat instead. When this happens, your fat tissue produces small amounts of an acidic substance called ketones.

Smaller levels of ketones are simply passed out of the body and cause no harm. If you have no insulin in your body, however, then higher levels of ketones are produced and can build up in your bloodstream and start to change the chemical balance of your blood. This causes a condition known as diabetic ketoacidosis.

What is diabetic ketoacidosis?

If your body continues to produce ketones to the extent that the chemical balance of your blood is affected, this causes diabetic ketoacidosis, or DKA. DKA causes vomiting and your blood glucose levels stay high. Your body tries to get rid of the ketones by producing more urine. Between vomiting and urinating, your body loses lots of water and you are at risk of severe dehydration. Dehydration from DKA can be fatal.

What are the symptoms of diabetic ketoacidosis?

You may experience any or all of the following symptoms:

• extreme thirst
• needing to urinate more than usual
• extreme tiredness
• mental confusion
• stomach pain
• vomiting and/or diarrhoea
• a strange taste in your mouth
• breath that smells like pear drop sweets

What should I do?

If you have any of the above symptoms, the first thing to do is to check your blood glucose.

If your blood glucose is higher than 15 mmol/L (or 13.9 mmol/L if you use an insulin pump), you should test for blood ketones. A ketone level of under 0.6 is normal. If your ketone level is 0.6–1.5 this is a warning sign that you are starting to produce ketones. Anything higher than 1.5 and you are at risk of diabetic ketoacidosis. Your local diabetes care team may have advised of slightly different glucose levels so if you are in any doubt about when you should test for ketones, please speak to your team directly.

When should I seek help?

• If you are unwell and feel like you need some support you should contact your diabetes care team. If you cannot contact them, you can phone your GP or an out-of-hours service.
• If your ketones are over 1.5 you should contact your on-call diabetes doctor or diabetes specialist nurse, or call an out-of-hours service. You should never feel that you are bothering medical staff unnecessarily – it’s much easier to deal with high blood glucose levels and small amounts of ketones if found early, rather than leaving it until you feel very unwell and need more intensive treatment.
• If you have any level of ketones and are feeling sick, are vomiting, have stomach pains or are feeling drowsy you should go to your nearest A&E department immediately.