Cause

Type 1 diabetes develops because the body's defense system (immune system) tells the body to destroy the beta cells in the pancreas that make insulin. It's not known what causes this immune response. Some people inherit the risk for type 1 diabetes. But even these people may not develop type 1 diabetes unless other factors, such as exposure to certain viral infections, are present.

• In infants and children, the beta cells usually are destroyed rapidly, resulting in a sudden rise in blood sugar level and a sudden onset of diabetes symptoms.
• In adults, the cells often are destroyed more slowly, resulting in a slower rise in blood sugar level and a slower onset of diabetes symptoms.

Certain genes make a person more susceptible while other genes seem to protect the person from the disease. A complex interaction between a person's genes and some environmental factors, such as having enteroviral infections—especially Coxsackie B infections—may increase the risk of developing the disease, but it does not mean that the person will definitely develop the disease.

In the past, experts thought that vaccines caused diabetes. But studies have found no link between getting a vaccination and getting type 1 diabetes.¹

Symptoms

Your (or your child's) symptoms of type 1 diabetes probably developed quickly, over a few days to weeks. These symptoms are caused by blood sugar levels rising above the normal range (hyperglycemia) and include:

• Frequent urination, which may be more noticeable at night. If your child has already learned to use the toilet, he or she may have started wetting the bed during naps or at night. The kidneys are trying to get rid of the excess sugar in the blood. In order to do that, they have to excrete more water. More water means more urine.
• Extreme thirst and a dry mouth. This happens if you lose, through frequent urination, enough water to become dehydrated.
• Weight loss. This happens because you are dehydrated. Weight loss may also happen if you are losing all of those sugar calories in your urine instead of using them.
• Increased hunger. You feel hungry because your body is not using all the calories that it can. Many of them are being excreted in urine.
• Blurred vision. Your vision may blur when sugar builds up in the lens of your eye. The sugar sucks extra water into your eye, which changes the shape of the lens and blurs your vision.
• Fatigue. You feel tired for the same reason you feel hungry. Your body is not using the calories you are eating, and your body is not getting the energy it needs.

All of these symptoms will get better or go away when your blood sugar levels are controlled.

If your blood sugar rose to very high levels at the time you were diagnosed with diabetes, you may have received treatment in a hospital for diabetic ketoacidosis, which is an emergency.

What symptoms might I have now?

Now that you are taking insulin injections, watch for signs of either high or low blood sugar. High blood sugar (hyperglycemia) usually develops slowly over a few days or weeks. But it can also develop quickly (in just a few hours) if you eat a large meal or miss an insulin dose. On the other hand, low blood sugar (hypoglycemia) can develop within 10 to 15 minutes. Children, especially very young children, are at greater risk for harm caused by very low blood sugar levels.

Watch for the following symptoms of high or low blood sugar. You (or your child) may not have the same symptoms every time, and you may have symptoms that are not listed.

• Symptoms of low blood sugar include sweating, weakness, and inability to concentrate. Severe low blood sugar can cause loss of consciousness and seizures.
• Symptoms of high blood sugar include increased thirst and increased urination.
• Signs of high or low blood sugar in young children can be confusing but may include paleness and a sudden change in emotion.