Sick day and ketone management for injections

  • Looking after your diabetes when you are unwell

    • It is essential that insulin is working in the body at all the timesYou can never stop insulin. 
    • Insulin doses may need to be changed when you are unwell. 
    • Monitoring of glucose and ketones will increase.
    • Always check ketone levels when you are unwell, regardless of what the glucose level is.
      • Whilst unwell, ketones should be checked every 4 hours, however, if they rise to 1.0 mmol/L or higher, they need to be more closely monitored every 2 hours. The advice on this page explains how to manage ketones depending on the blood glucose level (BGL).
    • If vomiting and ketones are present and you are unsure of appropriate treatment, call your diabetes treating team early for support with insulin dose adjustments.
    • Check your fingerprick BGLs when unwell, do not rely on continuous glucose monitor (CGM) for your glucose readings.  

    When to seek medical attention

    Diabetic Ketoacidosis (DKA) is a medical emergency. Signs of DKA include; vomiting, abdominal pain, rapid breathing, drowsiness. 

    If you or your child has any of these symptoms OR has ketones of 3.0 mmol/L or higher, call an ambulance by dialing 000. 

    Sick day management falls broadly into two different categories:

    1. Illnesses that cause Hyperglycaemia (High BGL’s)

    • Illness can trigger stress hormones that cause insulin resistance. This can lead to high BGLs.
    • Insulin doses may need to be adjusted and increased when managing these types of illnesses. 
    • Check BGL’s every 2 hours.
    • Check blood ketones every 4 hours, if ketones are 1.0 mmol/L or higher, see the information below. 
    • See your GP to treat underlying the illness / infection.
    • Some acute illnesses (asthma, croup etc) may be treated with steroid medication such as hydrocortisone, prednisolone or dexamethasone. Steroids such as these may cause high BGLs. 
    • Give pain relief to relieve headaches or sore throat. 
    • Encourage sugar free fluids to maintain hydration.

    2. Illnesses that cause Hypoglycaemia (Low BGL’s)

    • Vomiting, diarrhoea, nausea and reduced appetite can all lead to Hypoglycaemia.
    • Check BGL’s every hour.
    • Check blood ketones every 4 hours. Ketones can be produced during illness even with normal or low BGL’
    • Insulin doses may need to be decreased. Remember: Insulin can never be stopped but doses can be reduced to minimise the frequency of hypo with decreased appetite.
      • Never stop long-acting insulin injection (glargine/Ryzodeg®/Levemir®), although the usual dose might need to be reduced.  
      • Rapid acting insulin doses will need to be reduced with reduced appetite. Start by reducing NovoRapid®/Humalog® by 10% -20%. For example, if your usual doses of NovoRapid are 8 units pre meals, you may need to reduce these doses to 6-7 units NovoRapid pre meals and reviewing how this adjusted dose is going.   
    • Sip on sugar containing fluids e.g. sips of lemonade or lemonade icy poles or diluted juice. 
    • Mini doses of glucagon may be used to treat hypoglycaemia if unable to tolerate food or fluids.

    What to do if ketones are 1.0 mmol/L or higher

    • You’ll need to check BGL 1-2 hourly and ketones 2 hourly until blood ketones are less than 1.0 mmol/L. 
    • Use rapid-acting insulin (e.g. NovoRapid®/Humalog®) to treat elevated ketones 

    If BGL 15mmol/L or higher 

    1. Give an 'urgent dose' of rapid acting insulin immediately. This amount is 10% of your total daily insulin (TDD) using NovoRapid®/Humalog®. 

    • To do this: Add up all the insulin you usually have over 24 hours (rapid acting + long acting) and divide this by 10 to get 10% of the amount to inject as rapid acting insulin
      e.g. if your doses are; 4 units Novorapid® for each of breakfast, lunch and dinner and 8 units glargine at night. The TDD = 20 units. 10% of this is 20 divided by 10 = 2 units
      - If you are due NovoRapid®/Humalog® i.e. it is a meal time, add this 10% onto your usual meal time dose of NovoRapid®/Humalog®.
      - If it is not a meal time, give 10% of The TDD dose as an extra injection immediately.    

    2. Check ketones in 2 hours and seek medical advice if ketones remain 1.0 mmol/L or higher. 

    • An additional 10% of rapid acting insulin will be required if if BGL remains 15mmol/L or higher and ketones remain 1.0 mmol/L or higher after 2 hours.  

    Seek medical advice if ketones continue to rise.

    If your child has vomiting, abdominal pain, rapid breathing, drowsiness or has ketones of 3.0 mmol/L or higher, call an ambulance by dialing 000.

    If BGL is between 8.0mmol/L - 14.9mmol/L

    1. Give 5 -10% of TDD dose using rapid acting insulin (NovoRapid®/Humalog®).
          - If you are due NovoRapid®/Humalog® i.e. it is a meal time, add the 5-10% amount to your meal time dose.  
          - If it is not a meal time, give 5-10% of the TDD as an extra injection immediately.
           (To calculate the 5% amount: halve the amount you have worked out for 10%) 

    • Encourage extra carbohydrate to maintain the BGLs e.g. 6 x crackers or 1 slice of toast. 

    2. Check ketones in 2 hours. Another dose of rapid acting insulin may be required if ketones remain 1.0 mmol/L or higher. 

    Seek medical advice if ketones continue to rise.

    If BGL is between 4.0mmol/L – 7.9mmol/L

    • Encourage extra carbohydrate to maintain BGLs e.g. cracker or bread. 
    • Give your usual insulin doses with meals.
    • Check ketones in 2 hours and seek medical advice if ketones remain 1.0 mmol/L or higher. 

    If BGL is 3.9 mmol/L or lower

    • Treat hypoglycaemia and encourage sweetened fluids e.g. lemonade icy poles or diluted juice (fluid containing carbohydrates).
    • Seek medical advice if insulin is due. A reduction in the insulin doses will likely be needed. 
    • Check ketones in 2 hours and seek medical advice if ketones remain 1.0 mmol/L or higher.

    Last updated November 2024


  • Seek urgent medical attention or call an ambulance by dialing 000 if: 

    • You have had 3 vomits or diarrhoea or continued stomach pains, especially if these pains are associated with high BGLs.
    • If at any stage, ketones are 3.0 mmol/L or higher, you should give an 'urgent dose' of rapid acting insulin as explained above and present to hospital for urgent medical assessment. This situation has a high risk of diabetic ketoacidosis (DKA) which is a medical emergency.  Remember signs of DKA include; vomiting, stomach pain, rapid breathing, drowsiness.

    • After following the above advice, ketone levels are increasing or remain 1.0 mmol/L or higher. 

    The Royal Children's Hospital (RCH) Sick day service phone number 9345 5522 ask for the 'Diabetes sick day call' 7am – 9pm Monday – Friday (for patients of the RCH).