Hyperglycemic crisis, which includes Diabetic Ketoacidosis and Hyperglycemic Hyperosmolar State, is a common diagnosis in high acuity hospital units and admission rates continue to increase despite preventive strategies. While diabetic ketoacidosis remains a common cause of death in children and adolescents with type 1 diabetes, in adults reported mortality is variable and depends on the severity of metabolic derangement and the presence of other acute and chronic conditions. Hyperosmolar hyperglycemic state, and the overlap syndrome of hyperosmolar ketoacidosis, have a higher overall mortality though outcomes are improving. We discuss the diagnosis, epidemiology, and management strategies with particular reference to commonly encountered pitfalls in care and provide an updated perspective on the shifts in the epidemiology and novel management strategies for these important disorders.