Hypoglycaemia means an abnormally low level of sugar (glucose) in the blood. This is a dangerous state, as the brain is totally dependent on a constant supply of glucose as its sole provider of energy. It occurs in people with untreated or inadequately controlled diabetes (a 'hypo). Untreated hypoglycaemia may lead to unconsciousness, during which the brain may be damaged from lack of energy. Fortunately most people will have some warning that their blood glucose levels are too low, giving them time to eat or drink some carbohydrate-rich food.

Symptoms

Hypoglycaemia can cause headache, mental confusion, slurred speech, abnormal behaviour, loss of memory, numbness, double vision, temporary paralysis and seizures (fits). There is usually trembling, faintness and palpitations, and there may be profuse sweating. Behaviour is often irrational and disorderly and may be mistaken for drunkenness.

Causes

For people with diabetes, maintaining the correct blood glucose is a balance between the amount of insulin injected and the amount of food eaten. The commonest cause of a ‘hypo’, is a relative overdose of insulin. The dose taken may be the same as normal, but the carbohydrate intake may have been reduced or the amount of exertion been excessive so that fuel has been used up faster than normal.The drop in blood sugar can also happen with oral hypoglycaemic drugs (medicines to lower blood glucose, often used in type-1 diabetes).

Treatment

The immediate treatment is to take sugar, but follow this by longer-acting carbohydrate foods such as a biscuit. This will usually end an attack. People with insulin-dependent diabetes should carry such food with them at all times. Injections of the hormone glucagon can be used in an emergency, especially if the person is unconscious, during which NO food or drink should be given to them.