Hyperglycaemia (high blood sugar)
If you have hyperglycaemia and are worried about symptoms that are getting worse go to the emergency department at the nearest hospital or, call triple zero (000) and ask for an ambulance.
Key facts
- Hyperglycaemia is when you have too much glucose (sugar) in your blood.
- People with diabetes can be at risk of hyperglycaemia.
- Symptoms of hyperglycaemia include feeling thirsty, tired and needing to urinate (wee) a lot.
- There are many possible causes, such as not taking enough insulin or being sick or stressed.
- If your blood sugar is very high, or isn't going down with self-care at home, it's important to seek urgent medical attention to prevent complications.
What is hyperglycaemia?
Hyperglycaemia is having too much glucose (sugar) in your blood. A blood glucose level above 15mmol/L is considered hyperglycaemia.
What symptoms are related to hyperglycaemia?
If you have hyperglycaemia, you might:
- feel very thirsty
- need to pass urine (wee) frequently
- feel irritable, tired or lethargic
- have blurred vision
- develop recurrent infections, such as urinary tract infections or thrush
- show signs of dehydration
- lose weight
If you have type 1 diabetes and your hyperglycaemia gets worse, you might develop diabetic ketoacidosis (DKA). This is a medical emergency that requires urgent treatment.
Symptoms of DKA include:
- fruity-smelling breath
- nausea and vomiting
- abdominal pain
- shortness of breath
- dry mouth
- weakness or confusion
CHECK YOUR SYMPTOMS — Use the Symptom Checker and find out if you need to seek medical help.
What causes hyperglycaemia?
If you have diabetes, hyperglycaemia can happen for a range of reasons, including:
- not enough or missed insulin, or diabetes medication
- taking some medicines, such as steroid medicines
- unsuitable food choices
- drinking a lot of alcohol
- the amount of physical activity you do
Conditions that can also lead to hyperglycaemia include:
- being unwell
- being in pain
- being stressed, emotional or excited
- having an infection (such as thrush, cystitis or a wound infection)
When should I see my doctor?
If your high blood sugar doesn't go down, or you can't keep fluids down, see your doctor immediately, or go to your nearest emergency department.
If you have type 1 diabetes, it's important that you act on hyperglycaemia. If not treated, a high blood sugar level can lead to a serious condition called diabetic ketoacidosis.
Call 000 or go to the hospital emergency department if:
- you are sick and cannot keep any food or fluids down
- your blood glucose level stays above 15mmol/L and you have ketones in your blood or urine
- your symptoms are getting worse, and you are unable to manage your condition yourself
Make an appointment to see your doctor if:
- you have diarrhoea or vomiting but can eat and drink something
- you have a fever for more than 24 hours
- your blood glucose is above 15mmol/L even after taking your diabetes medicines
- you are finding it difficult to keep your blood glucose levels in the target range
If you have type 2 diabetes, an occasional high blood glucose level is not a reason to worry.
FIND A HEALTH SERVICE — The Service Finder can help you find doctors, pharmacies, hospitals and other health services.
How is hyperglycaemia treated?
If you have diabetes, your doctor should have discussed with you a diabetes management plan or a 'sick day' plan. Check your plan for what to do when your blood sugar is too high.
You may need to:
- drink plenty of water and avoid drinks containing sugar, alcohol or caffeine
- check your blood glucose level regularly
- check your urine (wee) or blood for ketones
- change your dose of insulin
If your blood glucose level remains high, even after following your diabetes management plan, you may need medical treatment with fluids, electrolytes or medicines. Call your health team for advice.
ASK YOUR DOCTOR — Preparing for an appointment? Use the Question Builder for general tips on what to ask your GP or specialist.
What are the complications of hyperglycaemia?
Short-term complications
If you have hyperglycaemia, a short-term complication is dehydration (not having enough fluids in your body).
If you have type 1 diabetes and your blood glucose level is high, you can develop diabetic ketoacidosis.
If you have type 2 diabetes and have very high blood sugar levels for a long period of time you can develop a condition called hyperosmolar hyperglycaemic state.
Both conditions can be dangerous and need emergency medical treatment.
Long-term complications
Long-term complications of persistent high blood glucose can be serious.
Some examples are:
- heart disease
- stroke
- kidney disease
- vision problems
- nerve problems
Can hyperglycaemia be prevented?
If you have diabetes, it may not be possible to prevent all cases of hyperglycaemia, but there are things you can do to help keep your blood sugar in your target range:
- Follow a healthy eating plan.
- Keep physically active.
- Maintain a healthy weight.
- Take your medicines as prescribed.
- Manage stress
- Discuss a 'sick day' plan with your doctor and follow it when you need to.
Resources and support
Visit Diabetes Australia to learn more about blood glucose monitoring.
You can also call the healthdirect helpline on 1800 022 222 (known as NURSE-ON-CALL in Victoria). A registered nurse is available to speak with 24 hours a day, 7 days a week.
Do you prefer to read in languages other than English?
The National Diabetes Services Scheme website has information in multiple community languages about living with diabetes.
Looking for information for Aboriginal and/or Torres Strait Islander people?
Diabetes Australia has resources for Aboriginal and/or Torres Strait Islander people living with diabetes.
Learn more here about the development and quality assurance of healthdirect content.
Last reviewed: November 2024
