Type 1 diabetes is an autoimmune disorder in which the immune system attacks and destroys the insulin-producing beta cells in the pancreas. As a result, the pancreas produces little or no insulin. Type 1 diabetes is also characterized by the presence of certain autoantibodies against insulin or other components of the insulin-producing system such as glutamic acid decarboxylase (GAD), tyrosine phosphatase, and/or islet cells.
When the body does not have enough insulin to use the glucose that is in the bloodstream for fuel, it begins breaking down fat reserves for energy. However, the breakdown of fat creates acidic by-products called ketones, which accumulate in the blood. If enough ketones accumulate in the blood, they can cause a potentially life-threatening chemical imbalance known as ketoacidosis.
Type 1 diabetes often develops in children, although it can occur at any age. Symptoms include unusual thirst, a need to urinate frequently, unexplained weight loss, blurry vision, and a feeling of being tired constantly. Such symptoms tend to be acute.
Diabetes is diagnosed in one of three ways — a fasting plasma glucose test, an oral glucose tolerance test, or a random plasma glucose test — all of which involve drawing blood to measure the amount of glucose in it.