English: What is diabetes mellitus? Diabetes mellitus is when there's too much glucose, a type of sugar, in the blood. Diabetes mellitus can be split into type 1, type 2, as well as a couple other subtypes, including gestational diabetes and drug-induced diabetes. This video covers the pathophysiology behind each type, complications (including diabetic ketoacidosis and hyperosmolar hyperglycemic state), symptoms, and management.