In hyperglycemic hyperosmolar nonketotic syndrome (HHNS), which finding would you most expect on assessment?

• A. Fruity breath and a high level of ketones in urine
• B. Severe dehydration and hypernatremia caused by hyperglycemia
• C. Exactly the same symptoms and signs as DKA
• D. Kussmaul respirations, nausea, and vomiting

Answer: (B)

HHNS is driven by extremely high glucose levels that cause massive water loss through osmotic diuresis, leading to a very dehydration state and a high serum osmolality. Because there is still enough insulin to suppress significant ketone production, there is little to no ketogenesis, so you do not see fruity breath or ketones in the urine and there is no major metabolic acidosis with Kussmaul respirations. The classic finding is severe dehydration with hypernatremia from the fluid losses due to hyperglycemia. This contrasts with DKA, where prominent ketosis, acidosis, fruity breath, and Kussmaul breathing are common.