Hypoglycaemia

Hypoglycaemia is a state of low blood glucose. The traditional definition of hypoglycaemia is a blood glucose level of less than 3.9 mmol/L, but in recent years it has been further subdivided into level 1 hypoglycaemia (3.0 to less than 3.9 mmol/L) and level 2 hypoglycaemia (less than 3.0 mmol/L). Level 3 hypoglycaemia, or severe hypoglycaemia, is defined as the presence of neurological symptoms that prevents people with diabetes to treat themselves, and requires an external party help to recover from hypoglycaemia. These symptoms include drowsiness, confusion, seizures, or loss of consciousness.

Hypoglycaemia is a terrifying experience for people with diabetes, especially when it occurs when they are not at home. It is the main limitation for insulin treatment, and fear of hypoglycaemia is a major reason why patients and diabetes care providers are hesitant to intensify insulin treatment. 

Severe hypoglycaemia can cause permanent neurological damage, and even death. It has been shown in multiple clinical trials that the risks of cardiovascular events such as heart attack and stroke are also increased after an episode of severe hypoglycaemia.

Hypoglycaemia in people with diabetes is almost always caused by either sulfonylurea or insulin treatment. These often happen when they become acutely ill, fasting, misses a meal, during treatment adjustments, or when they develop new or worsening kidney or liver impairments. Less common causes of hypoglycaemia include adrenal insufficiency, advanced liver disease, insulin-producing tumours (insulinoma), and rarely other tumors or medications.

Symptoms of hypoglycaemia include, but not limited to:

1. Tremor

2. Cold sweats

3. Light-headedness

4. Unusual hunger

5. Palpitations

6. Drowsiness or confusion

7. Seizures or coma

Some patients with diabetes who experienced recurrent hypoglycaemia may lose the ability to sense these symptoms altogether, called "hypoglycaemia unawareness". Whenever possible, each episode of suspected hypoglycaemia needs to be confirmed with blood glucose measurement, although this may not be possible in all situations.

The usual advise given to people with diabetes is called the "15 x 15 method", where they are advised to consume 15 gram of fast-acting carbohydrate, such as 3 teaspoons of table sugar, 3 candies, or half a glass of fruit juice, and recheck their blood glucose again after 15 minutes. This process can be repeated again until the blood glucose level rises above 3.9 mmol/L. Often they need to take a small snack after recovery, like a piece of bread or 3 pieces of biscuits, to prevent blood glucose from getting low again.

Unless specifically advised by the diabetes care provider, reducing or even omitting insulin dose after an episode of hypoglycaemia can be dangerous and cause the blood glucose to get excessively high. The best way is to get in touch with the diabetes care provider as soon as possible to get the next step of action.

Since hypoglycaemia often happen during acute illness, fasting, or treatment adjustment, monitoring blood glucose during these period is crucial to prevent hypoglycaemia. Advanced care plans on how to deal with low blood glucose during acute illness and fasting are useful, and are addressed in the sections on "Sick Day Plans" and "Diabetes and Ramadan".