What is diabetic ketoacidosis and how does insulin treat it?

Diabetic ketoacidosis, or DKA, is a life-threatening complication primarily of type 1 diabetes caused by absolute or relative insulin deficiency. Without insulin, cells cannot use glucose for energy and the body breaks down fat, producing ketone bodies that make the blood dangerously acidic. Symptoms include nausea, vomiting, abdominal pain, fruity breath odor from acetone, Kussmaul respirations meaning deep rapid breathing, and altered consciousness.