Type 1 diabetes: symptoms, causes, treatment and living with it

The NHS says the most common symptoms are peeing more than usual, especially at night, feeling very thirsty and drinking more than usual, feeling very tired, and losing weight without trying to or looking thinner. Children may have heavier nappies or start wetting the bed because they are peeing more. The NHS suggests remembering the 4 Ts: toilet, thirsty, tired, thinner.

Other symptoms can include blurred vision, breath that smells sweet or fruity (like nail polish remover or pear drop sweets), cuts and wounds taking longer to heal, and frequent infections or infections that do not get better, such as thrush or nappy rash.

The NHS says the symptoms develop quickly, over a few days or weeks. NHS inform says they usually develop over a few hours or days in young people and often take a few days or weeks in adults. If it is not treated, it can lead to a serious condition called diabetic ketoacidosis.

The NHS says type 1 diabetes is a condition where your body cannot make a hormone called insulin. Insulin helps your body use glucose (sugar) for energy. Without insulin the level of glucose in your blood becomes too high, so you need to take insulin every day to manage your blood glucose levels.

NHS inform describes it as a lifelong condition in which the pancreas does not produce insulin. It says high blood glucose can make you feel unwell in the short term and can, over time, seriously damage your organs.

Type 1 diabetes is different from type 2 diabetes, which the NHS says usually develops more slowly and is more common in older people and people who are overweight. The symptoms are similar, which is why a blood glucose test is needed.

The NHS says that when you are first diagnosed you will be treated in hospital by a specialist diabetes team, who show you how to treat your condition once you leave. The main treatment is taking insulin to manage your blood glucose levels, and you will be taught to keep them within a target range by checking your glucose regularly and adjusting your insulin doses.

You inject insulin several times a day using an insulin pen, or use an insulin pump. The NHS says too much insulin causes hypoglycaemia (hypos), and you will be taught how to recognise and treat a hypo. If you have type 1 diabetes you are entitled to free prescriptions for all your medicines.

Your care plan, according to the NHS, includes learning to match insulin to what you eat and drink (carbohydrate counting), what type of insulin is best, when to check glucose and your targets, HbA1c reviews 2 to 4 times a year, advice on diet, alcohol, driving, exercise and sick day rules, checks for complications and support for your wellbeing and mental health.

NHS inform says type 1 diabetes cannot be cured at the moment, and that alternatives to insulin injections and pumps, such as islet cell or pancreas transplants, are only suitable for a very small number of people because they need very strong drugs to suppress the immune system.

The NHS says an insulin pump is a small device worn on the skin that gives tiny amounts of insulin day and night, and that it can reduce hypos and improve glucose levels compared with injections. You may be able to get one on the NHS if you cannot reach your HbA1c target without serious hypos, or your HbA1c is too high despite careful management. Pumps are also recommended for children under 12 who cannot easily have several injections a day.

The NHS says hybrid closed loop systems, where a pump works with a continuous glucose monitor to give insulin automatically, are gradually being made available. NHS inform says most people with type 1 diabetes use a continuous glucose monitoring (CGM) device, and that people often aim for CGM values between 3.9 and 10 mmol/L at least 70% of the time.

HbA1c is your average blood glucose over the previous 2 to 3 months. NICE says the target is usually 48 mmol/mol (6.5%) for adults but a different target can be better for some people, and NHS inform says 53 mmol/mol is often recommended, so your own target is agreed with your team.

NHS inform says type 1 diabetes is an autoimmune condition: the immune system mistakes the cells in the pancreas for something harmful and attacks them. Without insulin the body breaks down its own fat and muscle, which causes weight loss and can lead to diabetic ketoacidosis.

The NHS says you are more likely to get it if you have other autoimmune conditions or if others in your family have type 1 diabetes or other autoimmune conditions. Diabetes UK says the exact causes are not known and that you are at a slightly higher risk if your mother, father, brother or sister has it.

The NHS and Diabetes UK both say it cannot be prevented.

The NHS says type 1 diabetes usually starts in children and young adults. Signs in children include peeing more, thirst, tiredness and weight loss, and younger children may have heavier nappies or start wetting the bed. Children may also be unwell with things like a cold, tonsillitis, tummy pain or nappy rash when they first get diabetes symptoms, which can make it harder to diagnose.

If you think your child might have diabetes, the NHS says you can ask a GP to do a finger-prick glucose test, and it can help to bring a sample of their pee. Ask for an urgent GP appointment or get help from NHS 111, and call 111 if the child is under 5.

The NHS says insulin pumps are recommended for children under 12 who cannot easily have injections several times a day, and that children under 12 will not need all the check-up tests that adults have. NHS inform says any parent whose child is diagnosed may need extra help and support, and that the aim of treatment is to help the child have a normal, healthy life.

The NHS says a GP who thinks you or your child could have type 1 diabetes will do a finger-prick test to check for high blood glucose, and may also test a sample of pee. If tests suggest type 1 diabetes, you will need to see a specialist in hospital to start treatment and have more tests, usually on the same day.

A diabetes specialist will usually confirm whether you have type 1 or another type of diabetes based on your age, weight and symptoms. If it is not clear which type you have, or tests do not show diabetes, extra blood tests may be needed. NHS inform says urine may be tested for ketones, and that HbA1c can be used to diagnose diabetes and to monitor long-term blood glucose.

The NHS says low blood sugar (hypoglycaemia or a hypo) is usually where blood sugar is below 4mmol/L. Symptoms can include hunger, dizziness, anxiety or irritability, sweating, shaking, tingling lips, palpitations, tiredness and confusion. To treat it, eat or drink something that raises blood sugar quickly, such as a small glass of fruit juice, 5 glucose tablets or 2 tubes of glucose gel, check again after 10 to 15 minutes, then eat something longer lasting once above 4mmol/L.

If someone is unconscious from a severe hypo, the NHS says not to give food or drink, to put them into the recovery position and to give a glucagon injection if one is available and you know how to use it. Call 999 if a glucagon injection is not available or the person has not recovered within 10 minutes.

Diabetic ketoacidosis (DKA) is a serious condition where a lack of insulin causes ketones to build up in the blood. The NHS says symptoms include thirst, peeing more, stomach pain, feeling or being sick, deep breathing, fruity-smelling breath, tiredness, sleepiness or confusion, usually developing over 24 hours but sometimes faster. It can be life threatening and needs urgent hospital treatment. It can happen when people first develop type 1 diabetes and have not yet been diagnosed, particularly children.

NHS inform says you will need to check your blood glucose regularly, take insulin each day, look out for the signs of hypos and attend your check-up appointments, and that blood glucose can be affected by exercise, illness, stress, alcohol, other medicines and hormone changes during your period. You should have sick day rules from your diabetes team for when you are ill.

On driving, NHS inform says you should always tell your insurer that you have type 1 diabetes, refer to DVLA guidelines and check your blood sugar before driving, and that most people with well treated type 1 diabetes should be able to have a Group 1 licence. The NHS says if you drive you need to check your blood sugar before each journey and every 2 hours while driving, and not drive for at least 45 minutes after a hypo has been treated.

The NHS recommends a diabetes course for everyone with type 1 diabetes, such as DAFNE or BERTIE, and says you should be offered a free group course within 1 year of diagnosis.

The NHS says you will have a diabetes check-up at least once a year, with an HbA1c test every 3 to 6 months, diabetic eye screening every 1 or 2 years, and a foot check every year. The check-up includes your weight, BMI, cholesterol, blood pressure, kidneys, thyroid, wellbeing and mental health.

Long-term complications are linked to high blood glucose over time and can include heart disease and stroke, foot problems from nerve damage and reduced blood supply, sight problems (diabetic retinopathy), nerve damage, kidney problems and gum disease. The NHS says you can lower your chances by managing your blood glucose as well as you can, eating a balanced diet, exercising and not smoking, and by going to all appointments.

The NHS says to ask for an urgent GP appointment or speak to your diabetes team if you notice changes to your sight, and to see a GP or diabetes nurse for any pain, tingling, numbness or blisters in your feet.

NHS inform says many women with diabetes have successful pregnancies, but high blood sugar very early in pregnancy can affect a baby's early development, so care teams are keen to discuss plans before you become pregnant. They will help you reach a safe blood glucose level for early pregnancy and keep it as normal as possible before and during pregnancy.

It adds that treatments such as blood pressure or cholesterol medicines often need to be changed or stopped before pregnancy, and that you should talk to your diabetes team as soon as possible if you find out you are pregnant. The NHS says hybrid closed loop systems may be available if you are pregnant or planning to get pregnant.

If type 1 diabetes is suspected, the NHS route is an urgent GP appointment or NHS 111, then same-day hospital specialist assessment. Care continues with a specialist diabetes team, with equipment such as a blood glucose meter and insulin delivery supplied. The NHS says you will have regular tests and check-ups with your diabetes team.

Some people choose a private endocrinologist or diabetes specialist for a second opinion or additional review. NHS care for type 1 diabetes, including insulin and monitoring equipment, remains available alongside, so ask how any private advice will be shared with your NHS team.