Hypoglycaemia (low blood sugar): symptoms, causes and what to do

The NHS lists symptoms of low blood sugar that can include feeling hungry, dizzy, anxious or irritable, sweating, shaking, tingling lips, heart palpitations, feeling tired or weak, changes in vision such as blurred vision, and feeling confused. If you have severe low blood sugar you may have a seizure or fit, or become unconscious.

Diabetes UK adds that everyone has different symptoms and that symptoms may change over time. Its list also includes going pale, feeling tearful, headache, lack of concentration and night sweats. It warns about hypo unawareness, where you have no symptoms of your blood sugars dropping, which it says can be dangerous.

The NHS says that if you have diabetes and get symptoms of low blood sugar, you should check your blood sugar if you can; if it is below 4mmol/L you need to take steps to treat it. The steps it sets out are:

• Eat or drink something that will raise your blood sugar quickly, such as a small glass of fruit juice or sugary fizzy drink, 5 glucose or dextrose tablets, 4 large jelly babies, or 2 tubes of glucose gel.

• Check your blood sugar after 10 to 15 minutes.

• If it is still below 4mmol/L, have another sugary drink or snack and check again after 10 minutes.

• Once your symptoms have improved and your blood sugar is above 4mmol/L, eat something that will keep it up for longer, such as some biscuits, a sandwich or your next meal if it is due.

The NHS says that if someone has very low blood sugar and becomes unconscious, you should not give them any food or drink because they will not be able to swallow safely. Put them into the recovery position, and give a glucagon injection straight away if one is available and you know how to use it. If they start to recover within 10 minutes of a glucagon injection and can swallow safely, give them food or drink that will raise their blood sugar, and stay with them until they have fully recovered.

Call 999 if you think someone has very low blood sugar and they are not responding normally or are unconscious, and a glucagon injection is not available or you do not know how to use it, you have given a glucagon injection and they have not recovered within 10 minutes, or they have been drinking alcohol.

The NHS says diabetes medicines treat the condition by lowering blood sugar but can sometimes make it go too low. This is common with insulin, and can also happen with some other diabetes medicines, such as gliclazide and glimepiride.

The NHS says it is rare to get low blood sugar if you do not have diabetes. It can sometimes be caused by conditions including malnutrition, Addison's disease and a growth (tumour) in the pancreas.

The NHS says to see a GP if you do not have diabetes and get symptoms of low blood sugar such as shaking, sweating, a fast heartbeat and feeling confused.

If you take medicine for diabetes, the NHS lists things that reduce the risk. Diabetes UK stresses that a hypo can happen quickly, so you should always have your hypo treatment with you.

• Follow the treatment plan agreed with your diabetes care team, including adjusting your insulin dose when you need to.

• Check your blood sugar regularly.

• Carry something with you that will raise your blood sugar quickly, such as sugary drinks, sweets or glucose tablets.

• Carry a glucagon injection kit and medical ID, and make sure family and friends know how to treat severe low blood sugar.

• Ask your care team about a continuous glucose monitor or flash monitor, and if you have type 1 diabetes and often have problems, about an insulin pump.

• Do not skip or delay meals, do not drink too much alcohol, and do not drink alcohol without eating.

The NHS says to see a GP if you have diabetes and you get low blood sugar often, have had severe hypos or have had hypos at night, or if you do not always recognise the symptoms. You can also speak to your diabetes care team.

The NHS says that if you drive, you need to check your blood sugar before each journey and then every 2 hours while driving. If you get low blood sugar, do not drive for at least 45 minutes after your blood sugar is back to normal. The DVLA has more information about diabetes and driving.

Diabetes care on the NHS is provided by your GP practice and a diabetes care team. Diabetes UK says you might be able to get things like glucose gel, glucose tablets and dextrose tablets on prescription, so ask your diabetes team.

If you do not have diabetes and have repeated symptoms of low blood sugar, your GP can look into possible causes. Private endocrinology services also investigate this, but results should be shared with your GP.