Diabetic ketoacidosis (DKA) is a medical emergency that can happen in people with diabetes mellitus. DKA happens mostly in people with Type 1 diabetes, although it may happen in some people that have Type 2 diabetes.

DKA happens when a person does not have enough insulin in their body. All of the cells in the body need glucose (sugar) to survive, because the body needs sugar to make energy. Insulin breaks down glucose into a form that the body can use for energy. Without insulin, sugar stays in the blood and cannot get into the cells. This causes high blood sugar levels and makes it impossible for the cells to use glucose to make energy.

DKA can be caused by not having enough insulin, eating too many carbohydrates, and sometimes physical or mental stress. DKA can also be a sign that a person has diabetes that has not been discovered, or is not being controlled well.

DKA is diagnosed through blood and urine testing. These tests will show high blood sugar, which does not happen with other forms of ketoacidosis.

DKA was first discovered around 1886. Before insulin therapy was first used in the 1920s, DKA almost always caused death.