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Dealing with illness

It is important to know how to cope with illness if you have diabetes, or if you know or care for somebody with the condition. You'll also need to know how to manage insulin or other diabetes medications, blood or urine tests, and diet during illness.

Illness and infections, as well as other forms of stress, will raise your blood glucose levels. As part of the body’s defence mechanism for fighting illness and infection, more glucose is released into the bloodstream and prevents insulin from working properly. This happens even if you are off your food or eating less than usual.

Diabetes and illness


People who do not have diabetes simply produce more insulin to cope, but when you have diabetes; your body cannot do this. As a result, your blood glucose levels rise, causing you to pass more urine and feel thirsty. This in turn can make you dehydrated. The symptoms of high blood glucose can add to those of the original illness or infection and make it much worse.

Dehydration and diabetes

Dehydration is made worse when you have a temperature or are being sick. In some cases, blood glucose levels can become so uncontrolled that treatment in hospital is necessary. Severe dehydration and very high blood glucose levels may be serious for both those with Type 1 and Type 2 diabetes. That’s why being prepared, and following the necessary steps when ill, is vital to manage your diabetes well and avoid the worst effects of illness.


Some conditions (eg Addison's disease, severe asthma, rheumatoid arthritis, and lupus) are treated with steroids. If you have diabetes, you may well find that your blood glucose levels rise while taking high doses of steroids for periods of time. This should not stop you taking steroids if your doctor has prescribed them, even if your blood glucose levels are affected, but you should discuss with your doctor how best to manage your diabetes while taking steroids. You may need an increase in medication or your medication to be changed. If the steroids have been prescribed for a short period to manage deterioration in your condition, your blood glucose levels will usually return to normal when you stop taking them.

Tips for dealing with illness

  • Don't panic – contact your diabetes team who will help you if you have any queries or if you are unsure about what to do.
  • You should keep taking insulin and / or most diabetes medications – even if you don't feel like eating. In some cases you may need to alter your dose – your diabetes team will be able to advise on this. However, if you are taking any of the SGLT2 inhibitors (such as dapagliflozin, canagliflozin, empagliflozin) it is advisable to stop taking these medications if you are unwell and unable to eat or drink. You also need to contact your diabetes team as soon as possible. 
  • Test your blood more often, at least every four hours, including during the night. If you don't test your blood glucose levels at home you should be mindful of signs of hypergylcaemia'
  • Stay well hydrated. Have plenty of unsweetened drinks to avoid dehydration, and eat little and often.
  • If your blood glucose level is 15mmol/l* or more, check urine/blood for ketones. If ketones are present, contact your diabetes team.
  • If you don't feel like eating, are feeling sick or can't keep any food down, replace meals with snacks or drinks containing carbohydrates, which will provide energy. Try to sip sugary drinks (such as fruit juice or non-diet cola or lemonade) or suck on glucose tablets or sweets like jelly beans. Letting fizzy drinks go flat may help keep them down. If you're vomiting, or unable to keep fluids down get medical help as soon as possible.

Accident & emergency (A&E)

You may be in a situation where you need medical attention for something other than diabetes, eg an accident or injury. This might involve a wait in the hospital for a while before being seen. Make sure you tell someone as soon as you arrive that you have diabetes and that you might need to eat to avoid going hypo (usually people are advised not to eat or drink while in A&E, in case they need surgery). If you feel you need to eat or drink, check with the staff first.

Hospital stay

You may have a stay in hospital (long or short). This may be for something diabetes related, or not. Here are some things to think about:

  • The hospital should provide the insulin you normally use – but this may take some time so take some with you to avoid delays.
  • Take your own supplies of diabetes equipment, eg blood-testing kit or pump supplies (they probably won't be able to provide this).
  • Ward staff should be up-to-date with your diabetes care, but do check that they have discussed it with your diabetes team. If they haven't yet, make sure they do.
  • Don't assume that everyone treating you will know you have diabetes – it's always better to be over-cautious and keep mentioning it.
  • While in hospital, your blood glucose levels may be higher or lower than normal. Stress and longer periods of inactivity are just two reasons why. Your blood glucose levels might need to be tested more often and treatment adjusted.
  • If you want to manage your diabetes care yourself while in hospital you should be supported


*millimoles per litre: a measurement of the concentration of a substance in a given amount of liquid

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