Diabetes – Type 1 diabetes
Diabetes is a lifelong condition that causes a person's blood sugar (glucose) level to become too high.
The hormone insulin – produced by the pancreas – is responsible for controlling the amount of glucose in the blood.
There are two main types of diabetes:
Type 1 – where the pancreas doesn't produce any insulin
Type 2 – where the pancreas doesn't produce enough insulin or the body’s cells don't react to insulin
This topic is about type 1 diabetes.
Another type of diabetes, known as gestational diabetes, occurs in some pregnant women and tends to disappear following birth.
It's very important for diabetes to be diagnosed as soon as possible, because it will get progressively worse if left untreated.
You should therefore visit your GP if you have symptoms, which include feeling thirsty, passing urine more often than usual and feeling tired all the time (see the list below for more diabetes symptoms).
Type 1 and type 2 diabetes
Type 1 diabetes can develop at any age, but usually appears before the age of 40, particularly in childhood. Around 10% of all diabetes is type 1, but it's the most common type of childhood diabetes. This is why it's sometimes called juvenile diabetes or early-onset diabetes.
In type 1 diabetes, the pancreas (a small gland behind the stomach) doesn't produce any insulin – the hormone that regulates blood glucose levels. This is why it's also sometimes called insulin-dependent diabetes.
If the amount of glucose in the blood is too high, it can, over time, seriously damage the body's organs.
In type 2 diabetes, the body either doesn't produce enough insulin to function properly, or the body's cells don't react to insulin. Around 90% of adults with diabetes have type 2, and it tends to develop later in life than type 1.
The symptoms of diabetes occur because the lack of insulin means that glucose stays in the blood and isn’t used as fuel for energy.
Your body tries to reduce blood glucose levels by getting rid of the excess glucose in your urine.
Typical symptoms include:
feeling very thirsty
passing urine more often than usual, particularly at night
feeling very tired
weight loss and loss of muscle bulk
The symptoms of type 1 diabetes usually develop very quickly in young people (over a few days or weeks). In adults, the symptoms often take longer to develop (a few months).
Causes of type 1 diabetes
Type 1 diabetes occurs as a result of the body being unable to produce insulin, which moves glucose out of the blood and into your cells to be used for energy.
Without insulin, your body will break down its own fat and muscle, resulting in weight loss. This can lead to a serious short-term condition called diabetic ketoacidosis, where the bloodstream becomes acidic and you develop dangerous levels of dehydration.
Type 1 diabetes is an autoimmune condition, where the immune system (the body's natural defence against infection and illness) mistakes the cells in your pancreas as harmful and attacks them.
Treating type 1 diabetes
It's important that diabetes is diagnosed as early as possible, so that treatment can be started.
Diabetes can't be cured, but treatment aims to keep your blood glucose levels as normal as possible and control your symptoms, to prevent health problems developing later in life.
If you're diagnosed with diabetes, you'll be referred to a diabetes care team for specialist treatment and monitoring.
As your body can't produce insulin, you'll need regular insulin injections to keep your glucose levels normal. You'll be taught how to do this and how to match the insulin you inject to the food you eat, taking into account your blood glucose level and how much exercise you do.
Insulin injections come in several different forms, with each working slightly differently. Some last up to a whole day (long-acting), some last up to eight hours (short-acting) and some work quickly but don't last very long (rapid-acting). You'll most likely need a combination of different insulin preparations.
There are alternatives to insulin injections, but they're only suitable for a small number of patients. They are:
insulin pump therapy – where a small device constantly pumps insulin (at a rate you control) into your bloodstream through a needle that's inserted under the skin
islet cell transplantation – where healthy insulin-producing cells from the pancreas of a deceased donor are implanted into the pancreas of someone with type 1 diabetes (read about the criteria for having an islet transplant)
a complete pancreas transplant
If diabetes is left untreated, it can cause a number of different health problems. Large amounts of glucose can damage blood vessels, nerves and organs.
Even a mildly raised glucose level that doesn't cause any symptoms can have damaging effects in the long term.
Living with diabetes
If you have type 1 diabetes, you'll need to look after your health very carefully. Caring for your health will also make treating your diabetes easier and minimise your risk of developing complications.
For example, eating a healthy, balanced diet and exercising regularlywill lower your blood glucose level. Stopping smoking (if you smoke) will also reduce your risk of developing cardiovascular disease.
If you have diabetes, your eyes are at risk from diabetic retinopathy, a condition that can lead to sight loss if it's not treated. Everyone with diabetes aged 12 or over should be invited to have their eyes screenedonce a year.
Symptoms of type 1 diabetes
The symptoms of type 1 diabetes can develop very quickly (over a few days or weeks), particularly in children.
In older adults, the symptoms can often take longer to develop (a few months).
However, they should disappear when you start taking insulin and you get the condition under control.
The main symptoms of diabetes are:
feeling very thirsty
urinating more frequently than usual, particularly at night
feeling very tired
weight loss and loss of muscle bulk
itchiness around the genital area, or regular bouts of thrush (a yeast infection)
blurred vision caused by the lens of your eye changing shape
slow healing of cuts and grazes
Vomiting or heavy, deep breathing can also occur at a later stage. This is a dangerous sign and requires immediate admission to hospital for treatment.
You should visit your GP immediately if you think you may have diabetes.
When to seek urgent medical attention
You should seek urgent medical attention if you have diabetes and develop:
a loss of appetite
nausea or vomiting
a high temperature
fruity smelling breath – which may smell like pear drops or nail varnish (others will usually be able to smell it, but you won't)
Hypoglycaemia (low blood glucose)
If you have diabetes, your blood glucose levels can become very low. This is known as hypoglycaemia (or a "hypo"), and it's triggered when injected insulin in your body moves too much glucose out of your bloodstream.
In most cases, hypoglycaemia occurs as a result of taking too much insulin, although it can also develop if you skip a meal, exercise very vigorously or drink alcohol on an empty stomach.
Symptoms of a "hypo" include:
feeling shaky and irritable
nausea (feeling sick)
A hypo can be brought under control simply by eating or drinking something sugary.
If it isn't brought under control, a hypo can cause confusion, slurred speech and, eventually, unconsciousness.
In this case, an emergency injection of a hormone called glucagon will be needed. Glucagon increases the glucose in your blood.
Hyperglycaemia (high blood glucose)
As diabetes occurs as a result of your body being unable to produce any, or enough, insulin to regulate your blood glucose, your blood glucose levels may become very high. This happens because there's insufficient insulin to move glucose out of your bloodstream and into your cells to produce energy.
If your blood glucose levels become too high, you may experience hyperglycaemia. The symptoms of hyperglycaemia are similar to the main symptoms of diabetes, but they may come on suddenly and be more severe. They include:
a dry mouth
a need to pass urine frequently
Left untreated, hyperglycaemia can lead to diabetic ketoacidosis. This is a serious condition, where the body breaks down fat and muscle as an alternative source of energy. This leads to a build-up of acids in your blood, which can cause vomiting, dehydration, unconsciousness and even death.
The Diabetes UK website has more information about diabetes symptoms.
Causes of type 1 diabetes
Type 1 diabetes occurs when the body is unable to produce insulin. Insulin is a hormone that's needed to control the amount of sugar (glucose) in your blood.
When you eat, your digestive system breaks down food and passes its nutrients – including glucose – into your bloodstream.
The pancreas (a small gland behind your stomach) usually produces insulin, which transfers any glucose out of your blood and into your cells, where it's converted to energy.
However, if you have type 1 diabetes, your pancreas is unable to produce any insulin (see below). This means that glucose can't be moved out of your bloodstream and into your cells.
Type 1 diabetes is an autoimmune condition. Your immune system (the body's natural defence against infection and illness) mistakes the cells in your pancreas as harmful and attacks them, destroying them completely or damaging them enough to stop them producing insulin.
It's not known exactly what triggers the immune system to do this, but some researchers have suggested that it may be due to a viral infection.
Type 1 diabetes is often inherited (runs in families), so the autoimmune reaction may also be genetic.
If you have a close relative – such as a parent, brother or sister – with type 1 diabetes, you have about a 6% chance of also developing the condition. The risk for people who don't have a close relative with type 1 diabetes is just under 0.5%.
Diagnosing type 1 diabetes
It's important to diagnose diabetes as early as possible, so that treatment can be started.
If you experience the symptoms of diabetes, you should visit your GP as soon as possible. They'll ask about your symptoms and may request a urine and blood test.
Urine and blood tests
Your urine sample will be tested to see whether it contains glucose. Urine doesn't usually contain glucose, but if you have diabetes, some glucose can overflow through the kidneys and into the urine. Your urine may also be tested for ketones (chemicals) that indicate type 1 diabetes.
If your urine contains glucose, a blood test can be used to confirm the diagnosis of diabetes. A sample of your blood will be taken in the morning, before you've had anything to eat, and it will be tested to measure your blood glucose levels.
If your blood glucose levels aren't high enough for your GP to diagnose diabetes, you may need to have an oral glucose tolerance test (OGTT), which is also sometimes referred to as a glucose tolerance test (GTT).
After drinking a glucose drink, samples of your blood will be taken every half an hour, for two hours. The samples will be tested to find out how your body is dealing with the glucose.
Glycated haemoglobin (HbA1c)
The glycated haemoglobin (HbA1c) test is another blood test that can be used to diagnose diabetes.
In people who've already been diagnosed with diabetes, the HbA1c test is often used to show how well their diabetes is being controlled.
The HbA1c test gives your average blood glucose level over the previous two to three months. The results can indicate whether the measures you're taking to control your diabetes are working.
There are blood tests for specific antibodies that can identify type 1 diabetes.
If you've been diagnosed with diabetes, it's recommended that you have your HbA1c measured at least twice a year. However, you may need to have your HbA1c measured more frequently if:
you've recently been diagnosed with diabetes
your blood glucose remains too high
your treatment plan has been changed
Unlike other tests, such as the GTT, the HbA1c test can be carried out at any time of day and doesn't require any special preparation, such as fasting. However, it's less reliable in certain situations, such as during pregnancy.
The advantages associated with the HbA1c test make it the preferred method of assessing how well blood glucose levels are being controlled in a person with diabetes.
HbA1c is also increasingly being used as a diagnostic test for type 2 diabetes, and as a screening test for people at high risk of diabetes.
Treating type 1 diabetes
There's no cure for diabetes, so treatment aims to keep your blood glucose levels as normal as possible and to control your symptoms to prevent health problems developing later in life.
If you've been diagnosed with diabetes, you'll be referred for specialist treatment from a diabetes care team. They'll be able to explain your condition in detail and help you understand your treatment. They'll also closely monitor your condition to identify any health problems that may occur.
Type 1 diabetes occurs because your body can't produce enough insulin. This means you'll need regular insulin treatment to keep your glucose levels normal.
Insulin comes in several different preparations, each of which works slightly differently. For example, some last up to a whole day (long-acting), some last up to eight hours (short-acting) and some work quickly but don't last very long (rapid-acting). Your treatment is likely to include a combination of these different insulin preparations.
If you have type 1 diabetes, you'll probably need insulin injections. Insulin must be injected, because if it were taken as a tablet, it would be broken down in your stomach – like food – and would be unable to enter your bloodstream.
When you're first diagnosed, your diabetes care team will help you with your insulin injections, before showing you how and when to do it yourself. They'll also show you how to store your insulin and dispose of your needles properly.
Insulin injections are usually given by an injection pen, which is also known as an insulin pen or auto-injector. However, injections are sometimes given using a syringe. Most people need two to four injections a day.
Your GP or diabetes nurse may also teach one of your close friends or relatives how to inject the insulin properly.
Insulin pump therapy
Insulin pump therapy is an alternative to injecting insulin. An insulin pump is a small device that holds insulin and is about the size of a pack of playing cards.
The pump is attached to you by a long, thin piece of tubing, with a needle at the end, which is inserted under your skin. Most people insert the needle into their stomach, but you could also insert it into your hips, thighs, buttocks or arms.
The pump allows insulin to continuously flow into your bloodstream at a rate you can control. This means you no longer need to give yourself injections, although you'll need to monitor your blood glucose levels very closely to ensure you're receiving the right amount of insulin.
Insulin pump therapy can be used by adults, teenagers and children (with adult supervision) who have type 1 diabetes. However, it may not be suitable for everyone. Your diabetes care team may suggest pump therapy if you have frequent episodes of low blood glucose (hypoglycaemia).
The Diabetes UK website has more information about insulin.
Monitoring blood glucose
An important part of your treatment is to make sure that your blood sugar level is as normal and stable as possible.
You'll be able to manage this using insulin treatment and by eating a healthy, balanced diet, but you will also have to regularly check your blood glucose levels to make sure they're not too high or too low.
Exercise, illness, stress, drinking alcohol, taking other medicines and, for women, changes to your hormone levels during your monthly period can all affect your blood sugar levels.
In most cases, you'll need to check your blood glucose levels during the day, both at home and at work or school, using a simple finger prick blood test. You may need to do this up to four or more times a day, depending on the type of insulin treatment you're taking. Your diabetes care team will talk to you about your ideal blood glucose level.
The normal blood sugar level is 4.0-7.0 mmol/l before meals and less than 9.0 mmol/l two hours after meals. Mmol/l means millimoles per litre, and it's a way of defining the concentration of glucose in your blood.
The Diabetes UK website has more information on testing your glucose levels.
Having your blood glucose levels checked
You'll be measuring your blood glucose yourself every day, to check your levels.
Your GP or diabetes care team will also carry out a different blood test every two to six months, called the HbA1c test.
This gives a clearer idea of how well your treatment plan is working, by measuring how stable your glucose levels have been over the past 6-12 weeks.
It measures the amount of haemoglobin, which is the oxygen-carrying substance in red blood cells that has glucose attached to it. A high HbA1c level may indicate that your blood glucose level is consistently high and that your diabetes treatment plan needs to be altered.
The ideal HbA1c target for people with diabetes is below 48 mmol/mol.
TheDiabetes UK website has more information about blood glucose levels.
Treating hypoglycaemia (low blood glucose)
Hypoglycaemia can occur when your blood glucose level becomes very low. It's likely that you'll develop hypoglycaemia from time to time.
Mild hypoglycaemia (or a "hypo") can make you feel shaky, weak and hungry, and can be controlled by eating or drinking something sugary, such as a fizzy drink (not a diet version), sugar cubes or raisins. You may also be able to take pure glucose, in the form of a tablet or fluid, if you need to control the symptoms of a hypo quickly.
If you develop severe hypoglycaemia, you can become drowsy and confused, and you may even lose consciousness. If this occurs, you'll need assistance from another person who may be able to give you a glucose gel rubbed into your cheeks or an injection of glucagon into your muscle. Glucagon is a hormone that quickly increases your blood glucose levels.
Your diabetes care team may show several of your family members and close friends how to inject glucagon or give you glucose gel, should you need it.
Once you begin to come round, you'll need to eat something sugary when you're alert enough to do so. If you lose consciousness as a result of hypoglycaemia, there's a risk that it could happen again within a few hours, so you'll need to rest afterwards and have someone with you.
If the glucagon injection into your muscle doesn't work, and you're still drowsy or unconscious 10 minutes after the injection, you'll need urgent medical attention.
You'll need to have another injection of glucagon straight into a vein, which must be given by a trained healthcare professional.
If you have type 1 diabetes, it's recommended that you carry identification with you so that people are aware of the problem if you become hypoglycaemic.
Islet cell transplantation
Some people with type 1 diabetes may benefit from a fairly new procedure known as islet cell transplantation. It involves implanting healthy islet cells from the pancreas of a deceased donor into the pancreas of someone with type 1 diabetes.
You may be suitable for an islet cell transplant if you've had:
two or more severe hypos within the last two years and you have a poor awareness of hypoglycaemia
a working kidney transplant, severe hypos and poor hypoglycaemia awareness, or poor blood glucose control even after receiving the best medical treatment
You may not be suitable for an islet cell transplant if you:
weigh over 85kg (13st 5.4lb)
have poor kidney function
need a lot of insulin – for example, over 50 units a day for a 70kg (11st) person
An islet cell transplant is a minor, low-risk procedure that's carried out under local anaesthetic.
The procedure has been shown to be effective at reducing the risk of severe hypos. So far, the results of islet cell transplants carried out in the UK have shown a significant reduction in the number of hypos, from 23 per person per year before transplantation to less than one per person per year afterwards.
TheDiabetes UK website has more information about islet cell transplants and hypoglycaemia.
People with type 1 diabetes who are having a kidney transplantfrom a donor may also be offered a pancreas transplant at the same time.
Others may be offered a pancreas transplant after they've had a kidney transplant because they’re already on anti-rejection tablets.
If you're having repeated, severe and life-threatening hypoglycaemic attacks, a pancreas transplant may also be recommended.
During the procedure, your faulty pancreas will be replaced with a healthy pancreas from a donor. This will allow you to get a new source of insulin.
Pancreas transplants are complicated operations and, like other types of major surgery, there's a risk of complications. In the UK, about 200 pancreas transplants are carried out each year, with more than 300 people on the waiting list.
The waiting time for a pancreas transplant is one to two years, because there's a shortage of suitable donor organs.
Treating hyperglycaemia (high blood glucose)
Hyperglycaemia can occur when your blood glucose levels become too high. It can happen for several reasons, such as eating too much, being unwell or not taking enough insulin.
If you develop hyperglycaemia, you may need to adjust your diet or your insulin dose to keep your glucose levels normal. Your diabetes care team can advise you about the best way to do this.
If hyperglycaemia isn't treated, it can lead to a condition calleddiabetic ketoacidosis, where the body begins to break down fats for energy instead of glucose, resulting in a build-up of ketones (acids) in your blood.
Diabetic ketoacidosis is very serious and, if not addressed quickly, it can lead to unconsciousness and, eventually, death.
The signs of diabetic ketoacidosis include:
frequently passing urine
tiredness and lethargy (lack of energy)
abdominal (stomach) pain
nausea and vomiting
smell of ketones on breath (described as smelling like pear drops)
collapse and unconsciousness
Your healthcare team will educate you on how to decrease your risk of ketoacidosis by testing your own blood for ketones using blood ketone sticks if you're unwell.
If you develop diabetic ketoacidosis, you'll need urgent hospital treatment. You'll be given insulin directly into a vein (intravenously). You may also need other fluids given by a drip if you're dehydrated, including salt solution and potassium.
The Diabetes UK website has more information about diabetic ketoacidosis.
Type 1 diabetes can lead to long-term complications. If you have the condition, you have an increased risk of developing heart disease, stroke and kidney disease. To reduce the chance of this, you may be advised to take:
anti-hypertensive medicines to control high blood pressure
a statin – such as simvastatin – to reduce high cholesterol levels
low-dose aspirin to prevent stroke
angiotensin-converting enzyme (ACE) inhibitor – such asenalapril, lisinopril or ramipril if you have the early signs of diabetic kidney disease
Diabetic kidney disease is identified by the presence of small amounts of a protein called albumin in your urine. It's often reversible if treated early enough.
Care standards for diabetes
The aim of treating diabetes is to help people with the condition control their blood glucose levels and minimise the risk of developing future complications.
The Diabetes National Service Framework was developed by diabetes clinical experts and patients with diabetes. Good diabetes care includes:
access to information and appropriate support for people with type 1 diabetes, including access to a structured education programme – such as Dose Adjustment for Normal Eating (DAFNE)
an agreed care plan, helping all people with diabetes to manage their care and lead a healthy lifestyle – including a named contact for their care
information, care and support to enable all people with diabetes to control their blood glucose, maintain an acceptable blood pressure and minimise other risk factors for developing complications
access to services to identify and treat possible complications – such as screening for diabetic retinopathy (where high blood glucose levels damage the retina at the back of the eye) and specialised foot care
effective care for all people with diabetes admitted to hospital, for whatever reason
The Diabetes UK website has more information about care from healthcare professionals.
Complications caused by diabetes
If diabetes isn't treated, it can lead to a number of different health problems. High glucose levels can damage blood vessels, nerves and organs.
Even a mildly raised glucose level that doesn't cause any symptoms can have damaging effects in the long term.
Heart disease and stroke
If you have diabetes, you're up to five times more likely to develop heart disease or have a stroke.
Prolonged, poorly controlled blood glucose levels increase the likelihood of developing atherosclerosis (furring and narrowing of your blood vessels).
This may result in a poor blood supply to your heart, causing angina (a dull, heavy or tight pain in the chest). It also increases the chance that a blood vessel in your heart or brain will become completely blocked, leading to a heart attack or stroke.
High blood glucose levels can damage the tiny blood vessels of your nerves. This can cause a tingling or burning pain that spreads from your fingers and toes up through your limbs. If the nerves in your digestive system are affected, you may experience nausea, vomiting, diarrhoea or constipation.
Retinopathy is where the retina (the light-sensitive layer of tissue) at the back of the eye is damaged. Blood vessels in the retina can become blocked or leaky, or can grow haphazardly. This prevents the light from fully passing through to your retina. If it isn't treated, it can damage your vision.
The better you control your blood sugar levels, the lower your risk of developing serious eye problems. Having an annual eye check with a specialist (an ophthalmologist or optometrist) can help pick up signs of a potentially serious eye problem early so that it can be treated.
If it's caught early enough, diabetic retinopathy can be managed using laser treatment. However, this will only preserve the sight you have, rather than make it better.
If the small blood vessels in your kidney become blocked and leaky, your kidneys will work less efficiently.
In rare, severe cases, this can lead to kidney failure and the need for dialysis (treatment to replicate the functions of the kidneys). In some cases, a kidney transplant may be necessary.
Damage to the nerves of the foot can mean that small nicks and cuts aren't noticed, which can lead to a foot ulcer developing. About 1 in 10 people with diabetes get a foot ulcer, which can cause serious infection.
If you develop nerve damage, you should check your feet every day and report any changes to your doctor, nurse or podiatrist. Look out for sores and cuts that don't heal, puffiness or swelling, and skin that feels hot to the touch. You should also have a foot examination at least once a year.
In men with diabetes, particularly those who smoke, nerve and blood vessel damage can lead to erection problems. This can usually be treated with medication.
Women with diabetes may experience:
a reduced sex drive (loss of libido)
reduced pleasure from sex
a reduced ability to orgasm
pain during sex
If you experience a lack of vaginal lubrication, or you find sex painful, you can use a vaginal lubricant or a water-based gel.
Miscarriage and stillbirth
Pregnant women with diabetes have an increased risk of miscarriageand stillbirth. If your blood sugar level isn't carefully controlled immediately before and during early pregnancy, there's also an increased risk of the baby developing a serious birth defect.
Pregnant women with diabetes will usually have their antenatal check-ups in hospital or a diabetes clinic. This allows doctors to keep a close eye on their blood sugar levels and control their insulin dosage more easily.
TheDiabetes UK website has more information about diabetes complications.
Looking after your eyes
Everyone who's on a diabetes register will be given the opportunity to have a digital picture taken of the back of their eye. Speak to your GP to register.
If your diabetes is controlled by medication, you're entitled to free prescriptions and eye examinations.
Some people with diabetes may be eligible to receive disability benefits and incapacity benefits, depending on the impact the condition has on their life.
The main groups likely to qualify for welfare benefits are children, elderly people, people with learning disabilities or mental health problems, and those with complications of diabetes.
People over 65 who are severely disabled, may qualify for a type of disability benefit called Attendance Allowance.
Carers may also be entitled to some benefit too, depending on their involvement in caring for the person with diabetes.
Staff at your local Citizen’s Advice Bureau (CAB) can check whether you're getting all of the benefits you're entitled to. Both they and your diabetes specialist nurse should also be able to give you advice about filling in the forms.
GOV.UK has more information about benefits, and the Diabetes UK website has further advice about the Disability Living Allowance (DLA).