Updated June 10, 2014.

Written or reviewed by a board-certified physician. See About.com's Medical Review Board.

Definition:

Diabetes mellitus is an older term that describes what we now simply call “diabetes.” The word mellitus literally means “honey-sweet.” Diabetes was first identified as a disease associated with "sweet urine," because when blood glucose is elevated (hyperglycemia), it spills glucose into the urine -- hence the term sweet urine.

Diabetes is characterized by an excess of blood glucose, or blood sugar, that builds up in the bloodstream because the body is not able to adequately process the sugar taken in through food.

High blood sugar is an abnormal state for the body and creates specific symptoms and possible long-term health problems if blood sugar is not managed well.

There are three main types of diabetes:

• Type 1 diabetes occurs when the pancreas stops or nearly stops producing the hormone insulin. Insulin is needed to enable blood glucose to be used for energy by the body. People with type 1 diabetes must take daily insulin injections. Type 1 diabetes has also been referred to as insulin-dependent diabetes and juvenile diabetes.
• Type 2 diabetes occurs when the body is unable to make effective use of the insulin the pancreas does make. This is often referred to as insulin resistance. Obesity is a major cause of insulin resistance in both adults and children. Type 2 diabetes has also been called non-insulin dependent diabetes and adult-onset diabetes.
• Gestational diabetes occurs in women who have high blood sugar during pregnancy but have not been diagnosed with diabetes previously. After delivery of the baby, many women see their blood sugar return to normal. Some women will go on to develop type 2 diabetes.

Also Known As: diabetes

Common Misspellings: melitus