Low blood glucose (hypoglycaemia)

Low blood glucose (also known as hypoglycaemia or hypo) can also occur in insulin pump users. You should always treat low blood glucose immediately. When you feel hypo symptoms take your rapid-acting carbohydrate as quickly as possible.

Reasons for low blood glucose can include:

• Overestimating carbohydrates and giving too much insulin as a bolus
• Giving a quick type bolus with slowly absorbed food
• Slow digestion of food
• Basal rate too high
• More activity than usual without setting a temporary basal rate
• Overcorrection for high blood glucose value
• Alcohol consumption
• Stress causes hypos in some people
• Around the time of the menstrual cycle
• Incorrect insulin to carbohydrate ratio
• Hot weather

Even if you do not have symptoms, if your blood glucose level is below 4 mmol/L you must treat it with a rapid-acting carbohydrate. Stop and treat immediately and follow the treatment guidelines below. Repeat blood glucose check after 5–10 minutes, if your blood glucose remains low take your rapid-acting carbohydrate again.

For blood glucose below 4 mmol/L: treat with rapid-acting carbohydrate.

For blood glucose below 4.5 mmol/L but above 4 mmol/L: eat carbohydrates.

If a hypo occurs:	Action
Within 1 hour of next meal	15–20 g rapid-acting carbohydrate
1–2 hours until next meal	15–20 g rapid-acting carbohydrate (consider an additional 10 g medium-acting carbohydrate)
More than 2 hours until next meal	15–20 g rapid-acting carbohydrate (consider an additional 20 g medium-acting carbohydrate)

Examples of rapid-acting carbohydrates include:

• 200 ml of concentrate orange juice
• 4–5 jelly babies
• 4–5 glucose tablets

Examples of medium-acting carbohydrates include:

• 1 slice bread sandwich (15 g) or 2 slice bread sandwich (30 g)
• Fruit or glass of milk or 1 biscuit (10–15 g)
• Your next meal

For a treatment guide for hypoglycaemia, have a look at the flowchart below:

You should consider the cause of your hypo and how to use pump features in future to either prevent it, reduce its severity, or assist in its treatment. The following factors can contribute to an increased risk of hypoglycaemia in insulin pump users:

• Not using a temporary basal reduction (TBR) when needed
• Delayed hypo post-exercise – have you used temporary basal reduction (TBR) for long enough?
• Alcohol may cause nocturnal or delayed hypo – have you considered temporary basal reduction (TBR)?
• Change of cannula site from an area of lipohypertrophy (lumpy skin) to normal skin
• Weight loss or change in lifestyle

Always try to think of the reason for your hypo so that you can learn from your experience. It is not necessary to stop the pump if you are having a hypo but it is important to treat it quickly.

The main difference compared with treating a hypo when you were taking insulin injections is that you may not need longer-acting carbohydrates such as a biscuit or a sandwich after your initial treatment (see guidance above).

Remember: if you are having frequent episodes of hypoglycaemia, or are unable to treat the hypo yourself, you should contact your diabetes team for advice.