How dangerous is hypoglycaemia? One of the patients I treated in my first stint in A&E was a middle-aged woman in a hypoglycaemic coma.
Of course, I didn't know that when I first came to treat her. She could as easily have been drunk - with an unconscious patient there are bound to be a lot of questions.
On the scant evidence I had, and while waiting for tests, I plumped for "hypoglycaemic coma".
This happens when a diabetic takes their insulin, then forgets to eat or eats too little, and the insulin drives down blood sugar to sometimes fatal levels.
I decided to give her glucose into a vein. Halfway through, she opened her eyes and asked for fish and chips.
This is a dramatic example of how hypoglycaemia can disable a diabetic.
In everyday life, it rarely gets that far.
But low blood sugar can cause symptoms you'd rather be without if, say, driving a car.
First of all, if stopped, you could be taken for drunk, as my patient in A&E could have been.
Before that, you can appear confused, have delayed reaction times, disturbed vision, problems walking and you can pass out.
None of these things are good at the wheel and as a result drivers with diabetes are nearly 20% more likely to have an accident.
So how can you tell if a hypoglycaemic attack is coming on? The early symptoms are easy to discount: blurred vision, sweating and feeling tired and irritable.
The main concern when you're driving is that low blood sugar will compromise your thinking and judgement.
Even among diabetics, awareness of these dangers is limited. In 2003, a study surveying sufferers in the EU and US, found that half of people with type 1diabetes and three-quarters of people with type 2 diabetes had not been informed of the dangers of hypoglycaemia while driving.
An analysis in November showed that people under 65 on a drug for type 2 diabetes who had been treated for hypoglycaemia in the past were 40% more likely to have an accident.
The University of Virginia, US, has devised blood glucose awareness training to teach people to guesstimate their blood sugar level. Or you could always just measure it before driving.