Hyperglycaemia

The digestive system breaks down carbohydrates into glucose. This simple sugar is then transported to each cell via the bloodstream. The pancreas secretes the hormone insulin, which allows the glucose to migrate from the blood into the cells. Once inside a cell, the glucose is ‘burned’ along with oxygen to produce energy.

Generally, blood glucose is very tightly regulated by insulin according to the person’s eating habits and activity levels. Hyperglycaemia means far too much glucose is circulating in the blood. A measurement of over 11mmol/L is usually considered a diagnosis of hyperglycaemia (and, hence, diabetes), if the measurement is taken at any time, or 7mmol/L if the test is done fasting.

Some of the conditions that can cause diabetes mellitus include Cushing’s syndrome and liver disease but, in most cases, there is no associated disease and people are said to have either Type I or Type II diabetes. Without treatment, diabetes can damage organs including the kidneys, eyes and nerves. It is also an important risk factor for coronary artery disease and other vascular diseases.

Symptoms
The symptoms of hyperglycaemia (diabetes) include:

• Excessive thirst
• Frequent urination
• Fatigue
• Unexplained weight loss
• Vision problems, such as blurring
• Increased susceptibility to infections such as thrush.

• Type I and Type II diabetes - diabetes is characterised by the body’s inability to use glucose. The two main types are insulin dependent diabetes mellitus (now referred to as Type I diabetes) and non-insulin dependent diabetes (now referred to as Type II diabetes).
• Gestational diabetes - a form of diabetes that some women develop during their pregnancy. Pregnancy blocks the action of insulin and can bring out a tendency to diabetes. Mothers with gestational diabetes are at increased risk of developing diabetes in subsequent pregnancies and in later life.

• Cushing’s syndrome - a collection of hormonal disorders characterised by high levels of the steroid hormones that act like cortisol, which is normally produced by the adrenal gland. Causes include tumours of the pituitary and adrenal glands, certain tumours in other areas of the body, and steroid drug therapy for inflammatory disorders.
• Pancreatitis - the pancreas makes the hormone insulin. Pancreatitis is inflammation of the pancreas, which can be either acute or chronic. Alcoholics are one group at risk of developing pancreatitis. Other causes of diabetes with chronic pancreatitis include the inherited conditions cystic fibrosis and haemochromatosis.
• Acromegaly - excess growth hormone secretion.
• Certain medications - including some diuretics (drugs that remove water) and steroids.
• Liver disease - such as cirrhosis of the liver.

• Random blood glucose test - a blood test that checks the blood glucose level, regardless of when the person last ate.
• Fasting blood glucose test - the person fasts so that a ‘baseline’ blood glucose level can be established by blood test. This is the most common way a diagnosis of diabetes is made.
• Oral glucose tolerance test - the person drinks a special preparation that contains glucose. A blood test is taken two hours later to check the blood glucose level.
• Glycosylated haemoglobin test - this test is a guide to the average level of blood glucose over the previous three months. The glycosylated haemoglobin test is typically used as a way to monitor the treatment of a person with diagnosed diabetes mellitus.
• Home blood glucose monitoring test - a person with diagnosed diabetes mellitus can test their blood glucose at home with a special kit. A drop of blood is placed on a strip of paper, which is then fed into a blood glucosemeter.

• Taking insulin and oral hypoglycaemic medication - usually for diabetes. Hypoglycaemia is a common result of treatment for diabetes, especially when the diabetes is well controlled. Occasionally, oral hypoglycaemic tablets are prescribed or given by mistake to people who do not have diabetes - this causes hypoglycaemia.
• Insulinoma - a tumour of the pancreas that triggers the overproduction of insulin.
• Liver failure - loss of the liver’s capacity to produce glucose can cause hypoglycaemia.

• Your doctor
• Juvenile Diabetes Research Foundation Australia Tel. (03) 9696 3866
• Diabetes Australia Tel. (03) 9654 8777
• Baker IDI Heart and Diabetes Institute Tel. (03) 9258 5000

• Hyperglycaemia means too much glucose is circulating in the blood and, when it is persistently high, it means the person has diabetes.
• Most people with hyperglycaemia have Type I or Type II diabetes. Occasionally, it is ‘secondary’ to another illness.
• Treatment is usually diet and oral hypoglycaemic tablets in Type II diabetes, although eventually some people require insulin. In Type I diabetes, insulin is always required.

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