Medical Conditions - Type 1 Diabetes

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Type 1 Diabetes

(Diabetes Type 1)

The Facts

Diabetes is a condition of elevated blood sugars in which the body does not make enough insulin and/or the insulin being made cannot be used properly by the body. The body’s main fuel is a form of sugar called glucose, which comes from food (after it’s been broken down). Glucose enters the blood and is used by cells for energy. To use glucose, the body needs a hormone called insulin, which is made by the pancreas.

Insulin is important because it allows glucose to leave the blood and enter the body’s cells. Diabetes develops when your body can’t make any or enough insulin, or when it can’t properly use the insulin it makes.

There are two main types of diabetes: type 1 and type 2. Type 1 diabetes develops when your body makes little or no insulin. When this happens, glucose can’t get into the cells for energy and remains in the blood, causing hyperglycemia (high blood sugar).

Type 1 diabetes is an autoimmune condition. Most people develop type 1 diabetes before the age of 30, but it can also occur in older adults. In North America, 5% to 10% of people with diabetes have type 1 diabetes. It occurs equally among women and men.


There is a genetic predisposition for type 1 diabetes, but the exact science behind the condition is not yet fully understood. There is also the need for certain environmental factors or "triggers" to be involved that lead to the condition.

While the exact cause of type 1 diabetes isn’t known, researchers believe the disease develops when a virus or environmental toxin damages the pancreas or causes the body’s immune system to attack the beta cells of the pancreas (called an autoimmune reaction). As a result, the beta cells of the pancreas can no longer produce enough insulin.

Without insulin, glucose in the blood can’t enter the cells in the body and blood glucose levels rise. The body begins breaking down fat and protein for energy instead of using glucose for energy.

Symptoms and Complications

Although some people have no symptoms, most people diagnosed with type 1 diabetes have the following signs and symptoms of hyperglycemia (high blood sugar):

  • blurred vision
  • decreased mental sharpness
  • extreme thirst and hunger
  • feeling tired (fatigue)
  • frequent need to urinate
  • frequent skin infections
  • weight loss despite having an increased appetite
  • slow-healing wounds

In some cases, emergency symptoms of very high blood sugar may develop. They include:

  • confusion
  • fast breathing
  • fruity-smelling breath (a sign of diabetic ketoacidosis)
  • loss of coordination
  • pain in the abdomen
  • shaking
  • slurred speech
  • unconsciousness
  • nausea
  • vomiting
  • fast heartbeat

It’s absolutely critical to get immediate emergency medical attention if any of the above emergency symptoms develop. Make sure you get to a hospital right away.

There are short- and long-term complications associated with diabetes. Short-term problems are hypoglycemia (low blood sugar) and hyperglycemia (high blood sugar). Taking too much insulin*, missing a meal, or over-exercising can make blood sugar go too low.

Symptoms of low blood sugar can come along very quickly, and they can include:

  • cold sweats
  • fast heartbeat
  • hunger
  • lightheadedness
  • numbness of the tongue and lips
  • shakiness
  • anxiety
  • nausea

In contrast, symptoms of high blood sugar (such as thirst, increased urination, or blurred vision) usually come on slowly and can be brought on by circumstances such as taking too little insulin, eating too much food, or during stressful times or illness. A serious condition called ketoacidosis can occur when blood sugar is high and there is not enough insulin circulating in the body. Diabetic ketoacidosis mainly affects people with type 1 diabetes and can be very dangerous if left untreated.

Long-term complications develop when blood sugars are high over a long period of time, such as eye, kidney, and nerve problems as well as damage to blood vessels.

Damage to the larger blood vessels can cause narrowing of large arteries (atherosclerosis), which can lead to heart attack, stroke, and poor blood flow to the legs. Damage to small blood vessels can affect the eyes (a condition called diabetic retinopathy), which is the leading cause of blindness in North America for people 20 to 74 years of age. It can affect the kidneys and lead to nephropathy, which is the leading cause of kidney failure in Canada. It can also affect the nerves that supply the extremities (legs and arms), leading to nerve damage called neuropathy.

Other long-term complications of type 1 diabetes include slowed movements of the stomach and intestines caused by nerve damage (diabetic gastroparesis), increased risk of infection, and skin problems (poor wound healing and ulcers).

Fortunately, many of the complications of type 1 diabetes can be prevented or at least delayed by keeping blood sugars under good control.

Making the Diagnosis

To diagnose diabetes, a doctor will check your blood sugar levels. If they are above a certain threshold, the diagnosis of diabetes can be confirmed.

Diagnosing diabetes can be done by measuring sugar levels in several ways:

  • fasting sugar (first thing in the morning)
  • random sugar (done at any time of the day)
  • sugar level 2 hours after a standard load of carbohydrates

Depending on the method chosen, a blood sugar level above a certain threshold will confirm the diagnosis.

Treatment and Prevention

Treatment of type 1 diabetes involves a comprehensive management plan that includes education (about diabetes, nutrition, and exercise), insulin treatment, and the prevention and treatment of complications. Many health care professionals (nurses, dietitians, doctors, specialists, pharmacists, social workers) can be part of a diabetes care team, but the most important member of the team is the actual person with diabetes.

It is important that people with type 1 diabetes learn about diabetes and its management, as this allows them to have greater involvement and control over their diabetes. Your doctor may refer you to a certified diabetes educator or a diabetes education clinic as part of your diabetes management.

Lifelong replacement therapy with insulin is needed for type 1 diabetes. Insulin treatment needs to be injected and can’t be taken by mouth, as it would be broken down in the stomach. There are many types of insulin available but most people with type 1 diabetes are on a combination of a rapid-acting insulin with meals and a long-acting insulin at bedtime. Instead of taking multiple injections per day, some people use an insulin pump, which is a small device that is worn and delivers a continuous amount of insulin under the skin.

Proper nutrition is important, and a dietary plan made in consultation with a dietitian should be part of diabetes care. Following a healthy, balanced meal plan helps control blood sugar. This means watching what you eat, when you eat it, and how much you eat. Nutrition as part of diabetes management is not as restrictive as it once was. To keep your sugars in check, you must achieve a balance between food and insulin.

Exercise also helps to improve blood sugar control. Lightweight training combined with aerobic exercise (such as jogging or walking) has been shown to help improve your body’s response to insulin. It also helps to reduce the risk of heart problems such as high blood pressure and heart attack. Exercise, however, can sometimes make blood sugars difficult to control for patients with type 1 diabetes. For this reason, it is important for patients to frequently monitor their blood sugars when exercising. Adjustments in food or insulin doses are sometimes needed during times of exercise.

As part of proper diabetes management, a person with diabetes should know the symptoms of abnormal blood sugar levels, their target blood sugar levels, and how to properly monitor blood sugar levels using a home glucose monitor. Blood glucose self-monitoring is necessary for all people with diabetes taking insulin. Your doctor or diabetes educator will help determine your blood sugar targets based on your medical history, risk factors (e.g., age), and lifestyle factors. For most people with diabetes, the target blood sugar levels are 4 mmol/L to 7 mmol/L before eating, and 5 mmol/L to 10 mmol/L 2 hours after eating.

Regular testing throughout the day will guide you and your doctor in determining how much insulin you need to keep your blood sugar levels close to your targets. Most people with type 1 diabetes should monitor their blood sugar levels at least 3 times a day or more. There are many different blood glucose meters available on the market. Before buying a meter, you should speak to your doctor, diabetes educator, or pharmacist about which ones are most suited to you needs.

Remember to always keep glucose tablets, candies containing sugar, or other sources of quickly absorbed glucose (e.g., juice, regular soft drinks) with you at all times to treat mild hypoglycemia. Your doctor, diabetes educator, or pharmacist can help you identify appropriate sources of glucose.

To prevent complications, it’s important to follow your diabetes management plan and keep your blood sugar levels as close to your targets as possible.

Here are some tips to help you stay healthy and prevent some of the long-term complications of diabetes:

  • foot care: Poor circulation and nerve damage caused by diabetes can reduce sensitivity in the feet. It’s important to check your feet regularly, looking for any blisters, cuts, or sores. Always keep your feet clean and dry and protect them by wearing socks and comfortable shoes. If you notice any changes in your feet, contact your doctor.
  • eye care: Eye problems (retinopathy) due to diabetes can ultimately lead to blindness if left untreated. People with type 1 diabetes should have their eyes checked by an eye doctor (ophthalmologist) within 5 years of diagnosis, and then every year if the eye exam is normal. By treating problems early, you can avoid serious complications.
  • skin care: High blood glucose and poor circulation can lead to skin problems, such as slow healing after an injury or frequent infections. Make sure you wash every day with a mild soap and warm water, protect your skin by using sunscreen, take good care of any cuts or scrapes with proper cleansing and bandaging, and see a doctor when cuts heal slowly or if an infection develops.


*All medications have both common (generic) and brand names. The brand name is what a specific manufacturer calls the product (e.g., Tylenol®). The common name is the medical name for the medication (e.g., acetaminophen). A medication may have many brand names, but only one common name. This article lists medications by their common names. For information on a given medication, check our Drug Information database. For more information on brand names, speak with your doctor or pharmacist.

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