Diabetic ketoacidosis (DKA), hyperglycaemic hyperosmolar state (HHS) and hypoglycaemia are frequent and serious complications arising among patients with type 1 diabetes mellitus (T1DM) and type 2 diabetes mellitus (T2DM). In the USA, ~145,000 cases of DKA occur each year1, 2. The rate of hospitalization for HHS is lower, accounting for <1% of all diabetes- related admissions3, 4. The frequency of emergency room visits for hypoglycaemia is similar to that reported for severe hyperglycaemia1, 5. Among hospitalized individuals, hypoglycaemia is a frequent complication of ongoing treatment for hyperglycaemia, with a reported incidence of 5–28% in intensive care unit (ICU) trials (depending on the intensity of glycaemic control)6, and 1–33% in non-ICU trials using subcutaneous insulin therapy7, 8.
Diabetic ketoacidosis (DKA), hyperglycaemic hyperosmolar state (HHS) and hypoglycaemia are serious complications of diabetes mellitus that require prompt recognition, diagnosis and treatment. DKA and HHS are characterized by insulinopaenia and severe hyperglycaemia; clinically, these two conditions differ only by the degree of dehydration and the severity of metabolic acidosis. The overall mortality recorded among children and adults with DKA is <1%. Mortality among patients with HHS is ~10-fold higher than that associated with DKA. The prognosis and outcome of patients with DKA or HHS are determined by the severity of dehydration, the presence of comorbidities and age >60 years. The estimated annual cost of hospital treatment for patients experiencing hyperglycaemic crises in the USA exceeds US$2 billion. Hypoglycaemia is a frequent and serious adverse effect of antidiabetic therapy that is associated with both immediate and delayed adverse clinical outcomes, as well as increased economic costs. Inpatients who develop hypoglycaemia are likely to experience a long duration of hospital stay and increased mortality. This Review describes the clinical presentation, precipitating causes, diagnosis and acute management of these diabetic emergencies, including a discussion of practical strategies for their prevention.