Glucose intolerance is an umbrella term for metabolic conditions which result in higher than normal blood glucose levels – hyperglycemia.

Western lifestyles have seen glucose intolerance become more common year on year.

What conditions are denoted by glucose intolerance?

Conditions which can be considered as glucose intolerance include:

• 
  Impaired fasting glucose
• 
  Impaired glucose tolerance
• 
  Pre-diabetes
• 
  Type 2 diabetes

What is glucose intolerance?

Glucose intolerance includes anyone with either impaired fasting glucose (IFG) or impaired glucose tolerance (IGT).

With the World Health Organisation’s definitions for IFG and IGT, glucose intolerance is defined as:


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• A
  
  fasting blood glucose level
  
  of above 6.0 mmol/L or
• A
  
  blood glucose level
  
  of over 7.8 mmol/L 2 hours after consuming 75g of glucose.

Symptoms of glucose intolerance

The symptoms of glucose intolerance match those of type 2 diabetes:

• 
  Feeling very thirsty
• Dry mouth
• 
  Extreme tiredness
• 
  Blurred vision
• Drowsiness
• 
  Frequent need to urinate
• 
  Loss of muscle mass

The NHS states that not everyone will get these symptoms and symptoms may not be so severe.

Glucose intolerance test

A number of tests can be used to diagnose forms of glucose intolerance.

Test performed to diagnose glucose intolerance include:

• 
  Fasting plasma glucose test
• 
  Oral glucose tolerance test
  (OGTT)

Treatment for glucose intolerance

Treatments for glucose intolerance will either require lifestyle changes or a combination of lifestyle changes and

anti-diabetic medication

Lifestyle changes involve taking part in regular physical activity, aiming to lose weight, if appropriate, and cutting down on smoking and alcohol as necessary.

If medication is advised, most people will start on a drug, taken in tablet form, called

metformin

Some people may need to take additional or alternative medication.

Hyperglycemia occurs when people with diabetes have too much sugar in their bloodstream.

Hyperglycemia should not be confused with

hypoglycemia, which is when blood sugar levels go too low. You should aim to avoid spending long periods of time with high blood glucose levels.

What is hyperglycemia?

Hyperglycemia, the term for expressing

high blood sugar, has been defined by the World Health Organisation as:

• Blood glucose levels greater than
  
  7.0 mmol/L
  
  (126 mg/dl) when fasting
• Blood glucose levels greater than
  
  11.0 mmol/L
  
  (200 mg/dl) 2 hours after meals

Although blood sugar levels exceeding 7 mmol/L for extended periods of time can start to cause damage to internal organs, symptoms may not develop until blood glucose levels

exceed 11 mmol/L

What causes hyperglycemia?

The underlying cause of hyperglycemia will usually be from loss of

insulin
producing cells in the pancreas or if the body develops resistance to insulin.

More immediate reasons for hyperglycemia include:

• 
  Missing a dose of diabetic medication, tablets or insulin
• 
  Eating more carbohydrates
  than your body and/or medication can manage
• 
  Being mentally or emotionally stressed
  (injury, surgery or anxiety)
• 
  Contracting an infection

What are the symptoms of hyperglycemia?

The

main 3 symptoms of high blood sugar levels

are increased urination, increased thirst and increased hunger.

High blood sugar levels can also contribute to the following symptoms:

• Regular/above-average urination
• Weakness or
  
  feeling tired
• 
  Loss of weight
• Increased thirst
• Vision blurring

Is hyperglycemia serious?

Hyperglycemia can be serious if:

• Blood glucose levels stay high for extended periods of time – this can lead to the development of
  
  long term complications
• Blood glucose levels rise dangerously high – this can lead to
  
  short term complications

In the short term

Short term complications of very high blood sugar levels include ketoacidsosis and hyperosmolar hyperglycemic nonketotic syndrome.

Ketoacidosis
is a dangerous complication that mainly affects people with type 1 diabetes but can also affect some people with type 2 diabetes that are dependent on insulin. The risk of ketoacidosis becomes significant if blood glucose levels rise above

15 mmol/l (270 mg/dl)

There is a higher risk of ketoacidosis if a dose of

insulin is missed
or during periods of

illness

A dangerous complication known as

hyperosmolar hyperglycemic nonketotic syndrome
can affect people with diabetes if blood glucose levels remain very high, above 33 mmol/l (600 mg/dl) for an extended period of time.

In the longer term

Regularly having high blood glucose levels for long periods of time increases the risk of organ damage occurring which can lead to health problems that are commonly referred to as the long term

complications of diabetes

Try to keep as close to the HbA1c target of 48 mmol/mol (6.5%) as this will reduce the chances of developing diabetes complications.

When aiming to achieve or get close to this target, ensure you do not put yourself at a high risk of regular or severe hypos.

• Read more on
  
  hypoglycemia

How to avoid and deal with hyperglycemia?

Minimising long time exposure to high blood sugar levels is one of the key objectives of

diabetes control

Testing

blood sugar levels
will help in managing hyperglycemia. People who take insulin may be able to take additional insulin. However, only take additional insulin if your doctor is happy for you to do so, as miscalculations could lead to dangerously low blood sugar levels.

Diabetes UK advise people with type 1 diabetes to

test for ketones
if blood glucose levels rise above 15 mmol/l or the signs of ketoacidosis appear. Contact your health team if high levels of ketones are present.

If blood glucose levels remain high for long periods of time, contact your health team for advice.