Hyperglycaemia (high blood sugar)

Hyperglycaemia is having too much glucose (sugar) in your blood. A blood glucose level above 15mmol/L is considered 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

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)

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.

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

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.

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.