What is dangerously high blood sugar for type 2 diabetes

Hyperglycemia is the technical term for high blood glucose (blood sugar). High blood glucose happens when the body has too little insulin or when the body can't use insulin properly.

What causes hyperglycemia?

A number of things can cause hyperglycemia:

• If you have type 1, you may not have given yourself enough insulin.
• If you have type 2, your body may have enough insulin, but it is not as effective as it should be.
• You ate more than planned or exercised less than planned.
• You have stress from an illness, such as a cold or flu.
• You have other stress, such as family conflicts or school or dating problems.
• You may have experienced the dawn phenomenon (a surge of hormones that the body produces daily around 4:00 a.m. to 5:00 a.m.).

What are the symptoms of hyperglycemia?

The signs and symptoms include the following:

• High blood glucose
• High levels of glucose in the urine
• Frequent urination
• Increased thirst

Part of managing your diabetes is checking your blood glucose often. Ask your doctor how often you should check and what your glucose sugar levels should be. Checking your blood and then treating high blood glucose early will help you avoid problems associated with hyperglycemia.

How do I treat hyperglycemia?

You can often lower your blood glucose level by exercising. However, if your blood glucose is above 240 mg/dl, check your urine for ketones. If you have ketones, do not exercise.

Exercising when ketones are present may make your blood glucose level go even higher. You'll need to work with your doctor to find the safest way for you to lower your blood glucose level.

Cutting down on the amount of food you eat might also help. Work with your dietitian to make changes in your meal plan. If exercise and changes in your diet don't work, your doctor may change the amount of your medication or insulin or possibly the timing of when you take it.

What if it goes untreated?

Hyperglycemia can be a serious problem if you don't treat it, so it's important to treat as soon as you detect it. If you fail to treat hyperglycemia, a condition called ketoacidosis (diabetic coma) could occur. Ketoacidosis develops when your body doesn't have enough insulin. Without insulin, your body can't use glucose for fuel, so your body breaks down fats to use for energy.

When your body breaks down fats, waste products called ketones are produced. Your body cannot tolerate large amounts of ketones and will try to get rid of them through the urine. Unfortunately, the body cannot release all the ketones and they build up in your blood, which can lead to ketoacidosis.

Ketoacidosis is life-threatening and needs immediate treatment. Symptoms include:

• Shortness of breath
• Breath that smells fruity
• Nausea and vomiting
• Very dry mouth

Talk to your doctor about how to handle this condition.

Medical IDs

Many people with diabetes, particularly those who use insulin, should have a medical ID with them at all times.

In the event of a severe hypoglycemic episode, a car accident, or other emergency, the medical ID can provide critical information about the person's health status, such as the fact that they have diabetes, whether or not they use insulin, whether they have any allergies, etc. Emergency medical personnel are trained to look for a medical ID when they are caring for someone who can't speak for themselves.

Medical IDs are usually worn as a bracelet or a necklace. Traditional IDs are etched with basic, key health information about the person, and some IDs now include compact USB drives that can carry a person's full medical record for use in an emergency.

How can I prevent hyperglycemia?

Your best bet is to practice good diabetes management and learn to detect hyperglycemia so you can treat it early—before it gets worse.

If you're new to type 2 diabetes, join our free Living With Type 2 Diabetes program to get help and support during your first year.

Hyperglycaemia is the medical term for a high blood sugar (glucose) level. It's a common problem for people with diabetes.

It can affect people with type 1 diabetes and type 2 diabetes, as well as pregnant women with gestational diabetes.

It can occasionally affect people who don't have diabetes, but usually only people who are seriously ill, such as those who have recently had a stroke or heart attack, or have a severe infection.

Hyperglycaemia shouldn't be confused with hypoglycaemia, which is when a person's blood sugar level drops too low.

This information focuses on hyperglycaemia in people with diabetes.

Is hyperglycaemia serious?

The aim of diabetes treatment is to keep blood sugar levels as near to normal as possible. But if you have diabetes, no matter how careful you are, you're likely to experience hyperglycaemia at some point.

It's important to be able to recognise and treat hyperglycaemia, as it can lead to serious health problems if left untreated.

Occasional mild episodes aren't usually a cause for concern and can be treated quite easily or may return to normal on their own. However, hyperglycaemia can be potentially dangerous if blood sugar levels become very high or stay high for long periods.

Very high blood sugar levels can cause life-threatening complications, such as:

• diabetic ketoacidosis (DKA) – a condition caused by the body needing to break down fat as a source of energy, which can lead to a diabetic coma; this tends to affect people with type 1 diabetes
• hyperosmolar hyperglycaemic state (HHS) – severe dehydration caused by the body trying to get rid of excess sugar; this tends to affect people with type 2 diabetes

Regularly having high blood sugar levels for long periods of time (over months or years) can result in permanent damage to parts of the body such as the eyes, nerves, kidneys and blood vessels.

If you experience hyperglycaemia regularly, speak to your doctor or diabetes care team. You may need to change your treatment or lifestyle to keep your blood sugar levels within a healthy range.

Symptoms of hyperglycaemia

Symptoms of hyperglycaemia in people with diabetes tend to develop slowly over a few days or weeks. In some cases, there may be no symptoms until the blood sugar level is very high.

Symptoms of hyperglycaemia include:

• increased thirst and a dry mouth
• needing to pee frequently
• tiredness
• blurred vision
• unintentional weight loss
• recurrent infections, such as thrush, bladder infections (cystitis) and skin infections

Symptoms of hyperglycaemia can also be due to undiagnosed diabetes, so see your GP if this applies to you. You can have a test to check for the condition.

What should my blood sugar level be?

When you're first diagnosed with diabetes, your diabetes care team will usually tell you what your blood sugar level is and what you should aim to get it down to.

You may be advised to use a testing device to monitor your blood sugar level regularly at home, or you may have an appointment with a nurse or doctor every few months to see what your level is.

Target blood sugar levels differ for everyone, but generally speaking:

• if you monitor yourself at home – a normal target is 4-7mmol/l before eating and under 8.5-9mmol/l two hours after a meal
• if you're tested every few months – a normal target is below 48mmol/mol (or 6.5% on the older measurement scale)

What causes high blood sugar?

A variety of things can trigger an increase in blood sugar level in people with diabetes, including:

• stress
• an illness, such as a cold
• eating too much, such as snacking between meals
• a lack of exercise 
• dehydration
• missing a dose of your diabetes medication, or taking an incorrect dose
• over-treating an episode of hypoglycaemia (low blood sugar)
• taking certain medicines, such as steroid medication

Occasional episodes of hyperglycaemia can also occur in children and young adults during growth spurts.

Treating hyperglycaemia

If you've been diagnosed with diabetes and you have symptoms of hyperglycaemia, follow the advice your care team has given you to reduce your blood sugar level.

If you're not sure what to do, contact your GP or care team.

You may be advised to:

• change your diet – for example, you may be advised to avoid foods that cause your blood sugar levels to rise, such as cakes or sugary drinks
• drink plenty of sugar-free fluids – this can help if you're dehydrated
• exercise more often – gentle, regular exercise such as walking can often lower your blood sugar level, particularly if it helps you lose weight
• if you use insulin, adjust your dose – your care team can give you specific advice about how to do this

You may also be advised to monitor your blood sugar level more closely, or test your blood or urine for substances called ketones (associated with diabetic ketoacidosis).

Until your blood sugar level is back under control, watch out for additional symptoms that could be a sign of a more serious condition (see below).

When to get urgent medical attention

Contact your diabetes care team immediately if you have a high blood sugar level and experience the following symptoms:

• feeling or being sick
• abdominal (tummy) pain 
• rapid, deep breathing
• signs of dehydration, such as a headache, dry skin and a weak, rapid heartbeat
• difficulty staying awake

These symptoms could be a sign of diabetic ketoacidosis or a hyperosmolar hyperglycaemic state (see above) and you may need to be looked after in hospital.

How to prevent hyperglycaemia

There are simple ways to reduce your risk of severe or prolonged hyperglycaemia:

• Be careful what you eat – be particularly aware of how snacking and eating sugary foods or carbohydrates can affect your blood sugar level.
• Stick to your treatment plan – remember to take your insulin or other diabetes medications as recommended by your care team.
• Be as active as possible – getting regular exercise can help stop your blood sugar level rising, but you should check with your doctor first if you're taking diabetes medication, as some medicines can lead to hypoglycaemia if you exercise too much
• Take extra care when you're ill – your care team can provide you with some "sick day rules" that outline what you can do to keep your blood sugar level under control during an illness.
• Monitor your blood sugar level – your care team may suggest using a device to check your level at home, so you can spot an increase early and take steps to stop it.

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