Types of Diabetes Mellitus

a girl taking testing her blood sugar with a prick

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Diabetes mellitus is a disease characterized by an excess of blood glucose (blood sugar). There are three common types of diabetes mellitus, type 1 diabetes, type 2 diabetes, and gestational diabetes. These conditions are all characterized by high blood glucose, and they can all cause symptoms of fatigue and increased urinary frequency.

Type 1 and type 2 diabetes can also produce long-term complications, including vision changes and an increased risk of heart disease and stroke. Gestational diabetes can cause complications during pregnancy and delivery. Medical management is available for all of these types of diabetes mellitus, which reduces the symptoms and the risk of complications.

Diabetes mellitus is different from the less common diabetes insipidus (DI), which is a rare kidney problem characterized by frequent urination and excessive thirst. While it is also called diabetes, DI does not cause blood sugar problems.

Insulin and Diabetes Mellitus

All three types of diabetes mellitus involve alterations in insulin and glucose metabolism. Glucose is a component of carbohydrates. It is the body's main energy source. Insulin is a hormone produced by the pancreas, a small organ in the abdomen near the small intestine. Insulin helps the body store and use glucose.

When there is not enough insulin (type 1 diabetes), or when the body doesn't respond to insulin as it should (type 2 diabetes and gestational diabetes), then blood glucose levels rise.

Types of Diabetes Mellitus

All three types of diabetes mellitus are fairly common. If you experience urinary frequency, increased thirst, episodes of lightheadedness, or unexplained weight changes, you should seek medical attention, as these could be symptoms of diabetes or another metabolic problem.

Early diagnosis is important to prevent complications. Diabetes mellitus is usually characterized by elevated blood glucose and the presence of excess glucose in the urine. Treatment depends on the type of diabetes mellitus.

Type 1 Diabetes

Type 1 diabetes occurs when the pancreas stops or nearly stops producing insulin. Type 1 diabetes has also been referred to as insulin-dependent diabetes and juvenile diabetes.

Type 1 diabetes usually develops during childhood. Before diagnosis, children may wet the bed, feeling very sleepy, and may have impaired growth and learning. In some instances, children develop seizures or loss of consciousness due to an extreme rise in blood sugar. Subtle symptoms or a medical emergency can trigger the diagnosis of type 1 diabetes.

It is not completely clear what causes type 1 diabetes. There is an increase of type 1 diabetes among family members, which suggests that there may be a hereditary component to the condition. There is also some evidence that it is an autoimmune disease (the body fighting its own pancreatic cells). It has also been suggested that type 1 diabetes may be triggered by a virus.

People with type 1 diabetes must take daily insulin replacement, either by injection or with an insulin pump. Ideally, blood glucose should be measured several times per day, and the insulin dose needs to be adjusted based on the blood glucose level and the food intake at each meal.

Type 2 Diabetes

Type 2 diabetes occurs when the body is unable to make effective use of insulin. This is often referred to as insulin resistance.

Type 2 diabetes has also been called non-insulin dependent diabetes and adult-onset diabetes. Some people experience fatigue or increased urination, but many people who have types 2 diabetes do not have any symptoms at all in the early stages. Later, complications, such as vascular disease, heart attacks, and strokes can develop.

Type 2 diabetes is often preceded by a condition described as pre-diabetes or a condition called metabolic syndrome. There is a great deal of overlap between these conditions, and they are both characterized by elevated blood sugar, high blood pressure, high cholesterol, and a high body mass index or obesity.

Often, weight and diet management can reverse pre-diabetes or metabolic syndrome and can prevent the development of type 2 diabetes.

Type 2 diabetes is treated with medication, diet, and lifestyle changes, such as weight loss and exercise.

Gestational Diabetes

If you develop a high blood sugar during pregnancy but have not been diagnosed with diabetes previously, you may have gestational diabetes. This condition can predispose your baby to growth and developmental issues and can complicate pregnancy and delivery. Regular monitoring of your blood sugar, your weight, and your baby's growth during pregnancy are necessary to minimize complications.

After the baby is born, many women see their blood sugar return to normal. However, some women will go on to develop type 2 diabetes, so it is important that you regularly have your blood sugar checked at your yearly doctor appointments if you have had gestational diabetes.

A Word From Verywell

Diabetes mellitus is a relatively common problem. While it can be well managed to prevent complications, all of the types of diabetes mellitus require close and consistent medical attention to prevent complications.

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