One of the most serious conditions associated with diabetes is called brittle diabetes. It is a major threat to diabetic patients and many don't even know they have it. So, in order to learn more about it and understand what causes it, we will discuss its definition, causes, and symptoms below. Brittle diabetes is also known as unstable diabetes or labile diabetes and is a form of diabetes mellitus (DM). It is different from the other forms because it typically has particularly serious consequences for diabetic patient. Brittle diabetes has also been reported to be an early type of adult-onset diabetes.