When your blood glucose levels are 15 mmol/L or higher, it’s called hyperglycaemia. You might experience some of the following symptoms:
- Excessive thirst
- Frequently passing large volumes of urine
- Feeling tired
- Blurred vision
- Infections (eg thrush, cystitis, wound infections)
- Abdominal pain
Some of the causes of high glucose levels are:
- Too much carbohydrate
- Not enough insulin
Illnesses and infections usually cause a rise in blood glucose levels. If you live with diabetes and you become unwell it’s important to follow your personalised sick day management plan. If you haven’t already developed a sick day management plan it is recommended to prepare one with your diabetes team.
Read our factsheet for more information on sick day management for people with type 1 diabetes.
When to take action
As a general rule, if you are unwell you should check your blood glucose levels at least every two hours. If your levels remain at 15 mmol/L or higher for more than 24 hours, and especially if you are unwell, you should seek advice from your doctor or diabetes team.
If you are living with Type 1 diabetes you may also need to check your ketones – either by a urine or finger-tip blood check. Your diabetes team will advise you if this is a necessary part of your diabetes management regime.
Very high blood glucose levels can lead to serious conditions (such as diabetic ketoacidosis in type 1 diabetes, or hyperosmolar hyperglycaemia in type 2) which can become life threatening.
Signs and symptoms which indicate you should seek urgent medical attention include:
- High blood glucose level (especially with ketones present > 1.0 on blood check if monitoring)
- Abdominal pain
- Rapid, shallow breathing
- Acetone smell on the breath
- Drowsiness (which may lead to coma)
These are medical emergencies and require treatment at a hospital.