Diabetic Ketoacidosis & Hyperosmolar Hyperglycemic State

Definition

DKA and HHS are acute, life-threatening complications of diabetes mellitus. DKA is characterized by hyperglycemia, metabolic acidosis, and ketonemia, primarily in type 1 diabetes. HHS is characterized by extreme hyperglycemia, hyperosmolarity, and dehydration without significant ketosis, primarily in type 2 diabetes.

Epidemiology

• DKA incidence: ~4–8 per 1,000 diabetic patients per year
• HHS is less common but has higher mortality (~10–20%)
• DKA more common in younger patients (type 1 diabetes)
• HHS more common in older adults with type 2 diabetes

Etiology

• Precipitating factors: infection, insulin omission, myocardial infarction, pancreatitis, surgery, stress
• DKA: absolute insulin deficiency
• HHS: relative insulin deficiency with severe dehydration

Pathophysiology

• Insulin deficiency → hyperglycemia → osmotic diuresis → dehydration
• DKA: increased lipolysis → ketone body production → metabolic acidosis
• HHS: hyperosmolarity from severe dehydration without significant ketone production
• Electrolyte disturbances: sodium, potassium, phosphate, magnesium