How to treat hypoglycemia

Take 15 g of fast-acting carbohydrate. That can mean 3-4 glucose tablets or 150 ml of fruit juice. Check your blood glucose again after 15 minutes and repeat the same amount if it is still below 70 mg/dL (3.9 mmol/L) [1].

The 15 g is a starting point, not a guarantee. If your blood glucose was already very low, or if you still have active insulin from an earlier bolus, you will very probably need a second 15 g of glucose [2]. What matters is that you recheck, rather than assume the problem has sorted itself out, as the figure below shows.

Pure glucose works fastest, and it comes as tablets, gel or powder. Next come clear fruit juice and sugar dissolved in water. Pure glucose corrects hypoglycemia without then sending your blood glucose too high [3].

Keep glucose in a few fixed places you know by heart and can reach without searching, such as your bag, your car, your desk and your bedside table. During an episode of hypoglycemia you have neither the patience nor the clear head to rummage through drawers.

Because they are high in fat, and fat slows down stomach emptying. The glucose they contain reaches the blood far later than you need it [4].

After you eat chocolate, nuts or ice cream, your blood glucose does not rise in the first few minutes, so you keep on eating, and an hour or two later it climbs well above target. Keep chocolate for your own pleasure, not for treating hypoglycemia.

Wait 15 minutes. That is the shortest interval in which fast-acting carbohydrate makes a meaningful difference to your blood glucose [1]. In children the amount is based on body weight, roughly 0.3 g for every kilogram, and here too about 15 minutes are needed before the level returns to normal [5].

Do not start over sooner, however unpleasant the wait feels. Repeating the dose every few minutes stacks the effects and takes you straight into hyperglycemia, followed by a correction dose and sometimes by another episode of hypoglycemia.

Take the same amount once more and look for the explanation. Most often it is insulin given recently, alcohol drunk earlier that day or a long bout of physical activity.

If your blood glucose is still low after three rounds of 15 g of glucose, or if you feel worse, you need medical help rather than a fourth round [6]. Contact your diabetes team, or at the very least tell the people around you. If confusion or drowsiness appears, the emergency services must be called.

In severe hypoglycemia the person can no longer help themselves. Sometimes they still follow simple instructions and can drink a juice on their own, and then you can help with glucose by mouth. If, however, they are confused, cannot swallow, are having a seizure or have lost consciousness, give nothing by mouth, because the risk of choking is very high [6].

If the person loses consciousness, turn them onto their side, give glucagon and call the emergency services immediately. Once they come round and can swallow safely, give them slow-acting carbohydrate and stay with them. Every severe episode of hypoglycemia must be reported to the diabetes team [1].

Glucagon comes as a nasal form, sprayed into one nostril, and as an injectable form. The nasal form has proved as effective as the injection at correcting insulin-induced hypoglycemia, and in practice it is gradually replacing it [7].

The people who need to know how to give glucagon are those around you, not you: family, colleagues, your coach, your teachers. As a rule, people without medical training give the nasal form faster and with fewer mistakes than the injection [8]. Show them where you keep the kit and check the expiry date from time to time.

If your next meal is more than an hour away, eat a snack with slow-acting carbohydrate so that your blood glucose does not fall again. Then write down what happened: the time, the reading, what you ate and how much active insulin you had on board [1].

Do not take insulin to "fix" the rise that follows treatment. This is the moment when most unnecessary correction doses are given. If the episodes keep coming back, this record is exactly what you should discuss with your diabetes team.

The treatment is the same by day and by night: 15 g of fast-acting carbohydrate and a recheck after 15 minutes. The difference is that at night you first have to wake up. This is where sensor alarms become extremely valuable [9].

Systems that automatically stop insulin delivery when they predict a fall towards hypoglycemia significantly reduce the number of night-time episodes [10]. The answer is not to eat extra in the evening "just to be safe", but to discuss your insulin doses with your diabetes team.

At the wheel, stop the car, treat and wait. Do not set off with a blood glucose below 90 mg/dL (5.0 mmol/L). In data recorded in real traffic, patients who set off above this level appear to be safe [11].

If hypoglycemia appears during exercise, you must stop the activity, take fast-acting carbohydrate and only resume once your blood glucose is fully back within your target range for exercise. Bear in mind that the risk of another episode stays high for several hours after training, not only during it [12].