1. Definition >    2. Lack of Insulin Production >   3. Symptoms >

Symptoms of type 1 diabetes are caused when glucose blocked from entering the body's cells instead builds up in the blood. The symptoms usually develop quickly, over a few hours. A person with undiagnosed type 1 diabetes may appear quite ill and complain of increased thirst, urination, and appetite as well as weight loss. If these symptoms are not treated quickly, a condition known as ketoacidosis can develop and lead to a dangerously high level of acid in the body -- the result of the body's inability to use glucose for energy.