Cause

Type 2 diabetes occurs when your blood sugar (glucose) levels get too high because:

• Your body isn't able to use insulin the right way. This makes it hard for your cells to get glucose from blood to make energy. This is called insulin resistance.
• Your pancreas doesn't make enough insulin to make up for the insulin resistance. As diabetes gets worse, your pancreas may make less and less insulin.

Symptoms

Not everyone has symptoms before they find out they have type 2 diabetes. But if you did have symptoms, they may go away when your blood sugar level returns to your target range.

Symptoms of high blood sugar

You may not have any symptoms of type 2 diabetes. That's because your blood sugar levels can rise so slowly over time that you don't notice that anything is wrong. Early symptoms of high blood sugar can include:

• Being very thirsty.
• Urinating a lot.
• Losing weight without trying.
• Having blurry vision.

The higher your blood sugar rises, the more likely you are to have symptoms. If you have higher-than-normal blood sugar and don't drink enough liquids, you can get dehydrated. This can make you feel dizzy and weak, and it can lead to an emergency called a hyperosmolar state.

Symptoms of low blood sugar

When your blood sugar is too low, it can also cause problems. Low blood sugar can occur suddenly. Symptoms of low blood sugar include:

• Sweating.
• Shakiness.
• Confusion.
• Loss of consciousness.

You're not likely to get low blood sugar unless you take insulin or some kinds of oral medicines for type 2 diabetes.

Symptoms and signs of complications

Some people already have complications of type 2 diabetes when they are diagnosed. That can happen because high blood sugar can creep up over time and cause problems without your knowing it. It's important to know about possible problems and their symptoms, such as:

• Numbness, tingling, burning pain, or swelling in your feet or hands. This could be a sign of diabetic neuropathy. For more information, see the topic Diabetic Neuropathy.
• Blurry or spotty vision or seeing flashes. This may be a sign of diabetic retinopathy. For more information, see the topic Diabetic Retinopathy.
• Cuts or sores that won't heal or that look infected. This could mean damage to blood vessels.
• Chest pain or shortness of breath. This may be a sign of heart disease or blood vessel problems (macrovascular disease).

If you have kidney damage, you may not notice symptoms. Early damage to your kidneys can only be found by urine tests for protein.