Diabetes mellitus, often simply referred to as diabetes, is a group of metabolic diseases in which a person has high blood sugar, either because the body does not produce enough insulin, or because cells do not respond to the insulin that is produced. This high blood sugar produces the classical symptoms of polyuria,polydipsia (increased thirst) and polyphagia (increased hunger).

Type I Diabetes:

Type 1 diabetes can occur at any age. However, it is most often diagnosed in children, adolescents, or young adults.

Insulin is a hormone produced by special cells, called beta cells, in the pancreas. The pancreas is found behind your stomach. Insulin is needed to move blood sugar (glucose) into cells, where it is stored and later used for energy. In type 1 diabetes, beta cells produce little or no insulin.

Without enough insulin, glucose builds up in the bloodstream instead of going into the cells. The body is unable to use this glucose for energy. This leads to the symptoms of type 1 diabetes.

Symptoms:

Being very thirsty

Feeling hungry

Feeling tired or fatigued

Having blurry eyesight

Losing the feeling or feeling tingling in your feet

Losing weight without trying

Urinating more often

Diabetes is caused by a problem in the way your body makes or uses insulin. Insulin is needed to move blood sugar (glucose) into cells, where it is stored and later used for energy.

When you have type 2 diabetes, your fat, liver, and muscle cells do not respond correctly to insulin. This is called insulin resistance. As a result, blood sugar does not get into these cells to be stored for energy.

Type 2 diabetes usually occurs slowly over time. Most people with the disease are overweight when they are diagnosed. Increased fat makes it harder for your body to use insulin the correct way.

Type 2 diabetes can also develop in people who are thin. This is more common in the elderly. Family history and genes play a large role in type 2 diabetes. Low activity level, poor diet, and excess body weight around the waist increase your risk. See also: Type 2 diabetes for a list of risk factors.

Symptoms:

Bladder, kidney, skin, or other infections that are more frequent or heal slowly

Fatigue

Hunger

Increased thirst

Increased urination

Pregnancy hormones can block insulin from doing its job. When this happens, glucose levels may increase in a pregnant woman's blood.

You are at greater risk for gestational diabetes if you:

Are older than 25 when you are pregnant

Have a family history of diabetes

Gave birth to a baby that weighed more than 9 pounds or had a birth defect

Have high blood pressure

Have too much amniotic fluid

Have had an unexplained miscarriage or stillbirth

Were overweight before your pregnancy

Symptoms:

Blurred vision

Fatigue

Frequent infections, including those of the bladder, vagina, and skin

Increased thirst

Increased urination

Nausea and vomiting

Weight loss despite increased appetite