The most pressing concern among people with hyperglycemia is diabetic ketoacidosis (DKA)/hyperosmolar hyperglycemic state. All of these patients should be evaluated as soon as possible, but the person with altered mental status is the highest priority. Neurologic deterioration occurs in patients with a plasma osmolality above 320 mosmol/kg, but stupor and coma can occur at lower osmolality. Hyperglycemia can cause changes in the refractive properties of the lens, leading to blurry vision. DKA can be precipitated by infection, so fever is an important finding. Abdominal pain is usually more prominent than headache in people experiencing DKA.