Hyperglycaemic describes the state of having hyperglycaemia — blood glucose elevated above the normal range. A hyperglycaemic episode may follow a missed insulin dose, overeating, infection, or stress; a hyperglycaemic patient presents with the classic symptoms of thirst, polyuria, and fatigue. Clinicians distinguish the mild, chronic hyperglycaemic state of poorly controlled diabetes — quietly damaging vessels over years — from hyperglycaemic emergencies: diabetic ketoacidosis in type 1 diabetes and hyperosmolar coma in type 2, both life-threatening and requiring hospital treatment. The adjective also labels the foods and conditions that raise blood sugar — the vocabulary of diabetes is built on keeping this one word at bay.