High & Low Blood Glucose Levels
Last edited on January 25, 2005

The aim of diabetes management is to keep blood glucose levels as close to the normal range as safely possible.

This is achieved by balancing multiple daily insulin injections, healthy eating, regular exercise and constant monitoring of blood glucose levels by taking small samples of blood from the fingertips.

A large number of factors influence blood glucose levels, including food intake, stress, hormonal changes, periods of growth, duration and type of physical activity, medications, alcohol, illness, infection, menstruation and fatigue.

When blood glucose levels swing too far in either direction, two emergency situations can develop: hypoglycaemia (low blood glucose) or hyperglycaemia (high blood glucose).

Hypoglycaemia (low blood glucose)

Hypoglycaemia, which is sometimes known as an insulin reaction, insulin shock or 'hypo', can come on rapidly.

Low blood glucose may be caused by eating too little food, leaving too much time between meals, too much physical activity or taking too much insulin.
The condition must be treated quickly because hypoglycaemia can worsen quickly.

Left untreated, the blood glucose level will continue to fall, starving the rest of the body of glucose and energy and leading to serious episodes such as blacking out. Eventually the person will fall into a diabetic coma.

When a person's blood glucose level drops below the normal range, the body's sympathetic nervous system reacts with symptoms including:

• sweating
• trembling
• lack of co-ordination
• slurred speech
• irritability
• crying
• rapid heartbeat
• paleness
• nausea or vomiting
• hunger
• lack of concentration
• loss of consciousness

A mild hypo is treated by consuming sugary food or drink followed by something more substantial, such as bread.

In most cases, early symptoms can be recognized and treated without further problems.

Hyperglycaemia (high blood glucose)

Hyperglycaemia usually develops gradually, although it can occur quickly if the person is ill. Symptoms include:

• excessive thirst
• frequent urine
• drowsiness
• lethargy, fatigue
• laboured breathing
• blurred vision

Causes of hyperglycaemia include insufficient insulin, dietary indiscretions, infections, stress or illness.

The Diabetes Control & Complications Trial showed that prolonged periods of high blood glucose levels increases the risk of serious health complications such as blindness, kidney disease, nerve damage and heart disease.

Hyperglycaemia is treated by administering extra insulin. If it is not recognised and corrected, hyperglycaemia can lead to ketoacidosis, a serious emergency. Ketoacidosis develops when the body, starved for glucose, breaks down stored fats for energy. The products of this process, ketones, are excreted in the urine and also found in the blood. The signs of ketoacidosis may include:

• Abdominal pains and vomiting
• Sweet acetone-smell to breath
• Rapid laboured breathing
• Flushed cheeks
• Dehydration

Hospitalisation is needed urgently.