Type 1 diabetes
- Dr Dulmini Kariyawasam, Consultant in Diabetes Endocrinology and Internal Medicine
Type 1 diabetes means your pancreas can’t make a hormone called insulin and so your body can't control the amount of sugar (glucose) in your blood. Your blood sugar level then becomes too high. Type 1 diabetes is a condition that you have for life.
About type 1 diabetes
There are two main types of diabetes: type 1 and type 2. Type 1 diabetes usually starts in children and is most often diagnosed between the ages of 10 and 14. But you can develop it as an adult too. In the UK, fewer than 1 in 10 people diagnosed with diabetes has type 1.
If you have type 1 diabetes, your body can’t produce the hormone insulin. This controls the amount of sugar (glucose) in your blood. When you need energy, insulin helps glucose move from your blood into body tissues. Without insulin, glucose stays in the bloodstream and your blood glucose level becomes too high.
Causes of type 1 diabetes
Type 1 diabetes is an autoimmune condition. That means the cause of type 1 diabetes is your body’s immune system – it attacks and destroys the cells in your pancreas that make insulin.
Type 1 diabetes seems to be genetic and you’re more likely to develop it if it runs in your family. But not everyone in these families develops diabetes, so there may be things in your environment that act as a trigger.
Symptoms of type 1 diabetes
Symptoms of type 1 diabetes include:
- the need to pee more than usual
- feeling constantly thirsty
- losing weight
- feeling extremely tired and weak
- blurred vision
Type 1 diabetes symptoms tend to start within days or weeks of it developing. If it isn’t diagnosed, the high blood glucose (blood sugar) levels can lead to a complication called diabetic ketoacidosis. This causes other symptoms, which include:
- feeling or being sick
- tummy (abdominal) pain
- a fast pulse
- shortness of breath
- extreme tiredness or drowsiness
If you notice these potential signs of type 1 diabetes in yourself or your child, contact a doctor. If the symptoms get worse, go to A&E (accident and emergency).
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Diagnosis of type 1 diabetes
Your GP will ask about your symptoms and examine you. They may prick your finger and test your blood to see if you need further tests. They may also test a sample of pee (urine).
If a GP suspects your child has diabetes, they’ll send you to hospital on the same day, to see a specialist diabetes team.
To fully diagnose diabetes, you need to have blood taken from a vein and tested to measure the level of glucose (sugar) in your blood. A blood glucose level above 11mmol/litre means it’s likely that you have diabetes. At the hospital, they’ll confirm the diagnosis and start treatment straight away.
Blood tests to diagnose diabetes are usually repeated, to confirm the diagnosis. You may have a ‘fasting glucose’ test. This means you have a blood test done after you haven’t eaten for at least 8 hours, usually first thing in the morning. You may also have blood tests for antibodies and proteins that can be markers for type 1 diabetes.
Management of type 1 diabetes
You can’t cure type 1 diabetes. But you should be able to live a normal life, with regular insulin and other measures to control your blood sugar. So type 1 diabetes shouldn’t stop you from doing any of the activities you’d normally do.
A team of diabetes specialists will usually manage your care. They’ll discuss your care plan with you and review it regularly. They’ll talk you through everything you need to know about living with diabetes and how to manage your condition.
Insulin
Taking insulin is an essential part of type 1 diabetes treatment. It helps to control your blood sugar and keep the level as close to normal as possible. Your doctor will start you on insulin as soon as possible after you’re diagnosed with type 1 diabetes. You’ll need to take it for the rest of your life.
There are short-acting and long-acting types of insulin. This makes a difference to how often you need to take it. You might have insulin:
- as regular injections
- through a pump
It’s most common to have injections. It’s best to inject in areas where there’s a layer of fat, usually your thighs, buttocks or tummy (abdomen). You usually have a pen-type device that you refill with insulin cartridges. You’re likely to need injections spaced throughout the day, such as before every meal.
Pumps deliver a regular amount of insulin through a small tube called a cannula that lies just under your skin. Your doctor may recommend a pump:
- for children up to 18
- for children and adults if injections aren’t controlling your blood sugar well enough, or you’re having severe low blood sugar (hypoglycaemia ) events – see Complications below
You can talk over the type of insulin you need and how you have it with your doctor or diabetes specialist nurse.
Diet
There are no restrictions on what you can or can’t eat if you have type 1 diabetes. But aim to follow a healthy, balanced diet that includes carbohydrates, fruit and vegetables with each meal. This will help to control your blood glucose level.
You’ll have to plan your insulin treatment quite closely around what you eat and how active you are. Your GP will refer you to see a dietitian who specialises in diabetes. Adults should be offered structured education classes such as the DAFNE (dose adjustment for normal eating) programme to help with this.
Your dietitian might talk to you about ‘carb counting’. This means matching the amount of insulin you take to the amount of carbohydrates you eat. It can help you to be more flexible with your mealtimes and what you eat, depending on the type of insulin you’re on.
Monitoring your blood glucose level
A key part of managing diabetes is checking your blood sugar regularly. The two main ways of doing this are:
- pricking your fingertip, and using a blood glucose testing strip
- wearing an electronic sensor that continuously measures your blood sugar (a continuous glucose monitor), or gives you a reading when you scan it (a flash monitor)
Your doctor will offer you a continuous glucose monitor (CGM) or a flash monitor. The difference between these is that you must actively scan the flash monitor with a scanner or your smart phone. CGMs measure glucose levels every three to five minutes, automatically.
CGM and flash monitors have a tiny wire in the centre. You put them on with an applicator and a pin pushes the wire just underneath your skin. One sensor can stay on for up to two weeks.
You still have to do finger pricks if you have a sensor, but less often. You check the accuracy of the sensor against a finger prick test from time to time. If you don’t want to wear a sensor, you can do finger pricks throughout the day instead.
Whichever method you use, you’ll need to check your blood sugar:
- first thing in the morning
- before meals
- before bed
- if you’re ill
- when exercising
- before driving
- if you have hypoglycaemic symptoms (see Complications below)
Blood tests at the doctors (HbA1c)
Your GP will also monitor how well you’re controlling your blood glucose level. They do this with a regular HbA1c blood test, usually every three to six months. This will measure how much glucose there is in your red blood cells. It can show how well you’ve been controlling your diabetes over the previous two or three months.
You’ll have a ‘target’ HbA1c to aim for. It’s important to stick to this to prevent long-term complications from diabetes.
Adjusting your insulin
As you get used to managing diabetes, you’ll learn how to adjust your insulin dose to maintain a healthy blood glucose level. You’ll have to take your diet and physical activity into account, and make extra adjustments if you’re ill.
Some insulin pumps can be connected to a CGM device to work out and adjust the insulin delivery to the amount you need automatically. These are called hybrid close loops, or an artificial pancreas. Even with a pump with CGM, you’ll have to make adjustments for meals.
Complications of type 1 diabetes
Type 1 diabetes complications can happen if your blood glucose (blood sugar) level becomes either too high (hyperglycaemia), or too low (hypoglycaemia).
Hyperglycaemia
Your blood sugar can become too high if you:
- become unwell
- feel stressed
- miss an insulin dose
- don’t match the amount of carbohydrate you eat with your insulin dose
You may find that you’re thirstier than usual, need to pee more often and feel tired.
Without enough insulin, chemicals called ketones build up in your blood. This can make you feel extremely tired, feel sick or vomit. Some people notice their breath has a distinctive fruity smell, like pear drops. You’ll have a ketone monitor to test your blood. Your doctor will tell you when to check your ketone level, and what to do if it’s too high.
Very high levels of ketones are dangerous. You can develop a condition called diabetic ketoacidosis (DKA). This is a medical emergency. You can become severely dehydrated and go into shock. If you think you may be at risk of DKA, get medical help straight away.
Long-term hyperglycaemia
Over time, if your blood sugar is frequently too high, it can damage body tissues and cause long-term complications. You’ll be at risk of:
- kidney disease
- nerve damage, which can cause tingling, burning or numbness
- foot problems, including infections, ulcers and problems related to lack of blood flow
- damage to your eyes, leading to blindness
- heart disease and stroke
- infections that are frequent or don’t go away, especially urinary infections
Many of these problems are caused by high glucose levels damaging the smallest blood vessels, such as those in the kidneys, eyes and heart.
If you have numb feet, you may not notice small injuries, which can then get worse and develop into ulcers.
Hypoglycaemia
This means your blood sugar level is too low, usually below 4mmol/litre. It’s often called a ‘hypo’. It can happen if you take too much insulin, skip or delay a meal or misjudge the amount of carbohydrate you need. It can also happen if you’re more active than usual or if you drink alcohol.
Most people get warning signs when their glucose level begins to fall. These include:
- feeling hungry
- sweating a lot
- feeling your heart pounding
- feeling lightheaded
- being anxious or irritable
- feeling shaky
- tingling lips
If your blood glucose level continues to fall, you may start feeling dizzy, confused, weak and lethargic. You may also have blurred vision.
Hypoglycaemia can be dangerous if not dealt with quickly. As soon as you notice symptoms, you need to eat or drink 10 to 20g of a fast-acting carbohydrate straight away. That’s about three to six glucose tablets, one or two tubes of glucose gel, or up to 180ml of a full-sugar fizzy drink, for example.
Check your blood glucose after 10 to 15 minutes and if it hasn’t returned to normal, have something more to drink or take more glucose tablets. Once your blood glucose starts to get back to normal, you may need to eat something that contains longer-lasting carbohydrates, such as a sandwich or some cereal.
If you have a hypo and lose consciousness, you should have a prepared injection of a medicine called glucagon. Your healthcare team will show family members or a friend how to give it to you in case of emergency. Make sure family and friends know that they’ll need to call for emergency help immediately if you don’t have glucagon, or your blood glucose level doesn’t return to normal after taking it. After a severe hypo, you’ll need to have a review with your specialist diabetes team.
It’s a good idea to wear a medical emergency identification bracelet or similar, so that people know you have diabetes and take insulin.
Living with type 1 diabetes
Following a healthy lifestyle can help to control your blood glucose (blood sugar) and reduce your risk of complications.
What you eat is important for your general health. However, it will only help to control your blood sugar if you match the carbohydrate you eat to your insulin dose.
A healthy, balanced diet means low in fat, sugar and salt, and with at least five portions of fruit or vegetables every day. This will help you to keep to a healthy weight and prevent cardiovascular disease.
If you smoke, try to stop. Smoking is particularly bad if you have diabetes. It increases your risk of circulatory problems, heart disease and stroke, which is already raised because of your diabetes.
Exercise
Keeping active can help to lower your blood glucose level and lower your risk of diabetes complications, including heart disease and stroke. It can also help you to stay a healthy weight. Even if you don’t do any sports, you can get exercise from daily activities such as housework or gardening.
Being more active will increase your body’s need for energy. You may need to eat before or after you exercise and may need to adjust your insulin. Check your blood sugar before and after you do any exercise.
Alcohol
If you have type 1 diabetes, alcohol on an empty stomach can increase your risk of a hypo. Alcohol can also make the signs of a hypo less clear. Check your blood glucose regularly if you’re drinking. Otherwise, general health advice applies: have no more than 14 units of alcohol a week, spread over several days.
Driving
Tell the Driver and Vehicle Licensing Agency (DVLA) when you’re diagnosed with type 1 diabetes. By law, you must check your blood sugar no more than 2 hours before you start any journey. Check again every 2 hours during a journey. If it’s less than 5mm/l, you can’t drive. Have a snack, wait 45 minutes and check again. Keep glucose tablets, gel or a fizzy drink in the car in case your blood sugar starts to dip.
If you develop any sight problems or have a severe hypo, you must tell the DVLA. There are stricter rules for commercial driving, so check the DVLA website for more information.
To diagnose diabetes, you need to have a blood test. This is usually repeated to make sure as blood glucose (sugar) levels can vary.
See our section on diagnosing type 1 diabetes for more information.
Type 1 diabetes is usually diagnosed in children, but it can sometimes be diagnosed in adults.
See the section: About type 1 diabetes.
Early signs of type 1 diabetes usually include feeling very thirsty, peeing a lot and feeling very tired.
See our section on type 1 diabetes symptoms for more information.
Your body can’t get energy to your body’s cells if you have diabetes. This means that if type 1 diabetes is untreated, it will be fatal. But if you manage it well, there’s no reason why you can’t live a perfectly normal life.
See our section on managing type 1 diabetes for detailed information.
Taking insulin is an essential part of type 1 diabetes treatment. Following a healthy, balanced diet that includes carbohydrates , fruit and vegetables with each meal is also important. A team of diabetes specialists will usually manage your care.
See our section on managing type 1 diabetes for more information.
Type 2 diabetes
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- Rachael Mayfield-Blake, Freelance Health Editor
