Ketoacidosis-resistant diabetes mellitus is a complex medical term that refers to a rare form of diabetes that is resistant to ketoacidosis, a potentially life-threatening complication of diabetes. Synonyms for this condition include ketosis-resistant diabetes, atypical diabetes, type 1b diabetes, and idiopathic diabetes. Ketosis-resistant diabetes describes the inability of the body to produce enough insulin to convert glucose into energy, which results in higher levels of ketones, a type of acid, in the bloodstream. Atypical diabetes refers to the unusual presentation of the disease, while type 1b diabetes and idiopathic diabetes both indicate a form of diabetes that is not caused by autoimmune destruction of the pancreas.