What key difference distinguishes DKA from hyperosmolar hyperglycemic state (HHS)?

One of the key differences that distinguishes diabetic ketoacidosis (DKA) from hyperosmolar hyperglycemic state (HHS) is the presence of urinary ketones. In DKA, the lack of insulin leads to increased lipolysis and ketone body production, resulting in acidosis and elevation of ketones in the urine. This is a hallmark feature of DKA and helps in the diagnosis of the condition, as the accumulation of ketones contributes to a significant metabolic acidosis.

In contrast, HHS generally occurs in the setting of a hyperglycemic state without significant ketosis. Patients with HHS have high serum glucose levels that can exceed 600 mg/dL, but they typically do not produce significant amounts of ketones because there is some level of insulin present that prevents full lipolysis and ketogenesis. Therefore, the presence of urinary ketones serves as an important distinguishing factor between the two conditions, with DKA showing marked ketonuria and HHS showing little to none.

While factors such as patient age, glucose levels, and severity of acidosis are relevant clinical considerations, they do not serve as definitive distinguishing characteristics in the same way that the presence of urinary ketones does.