DKA and HHS

A 28-year-old man with type 1 diabetes mellitus presents to the emergency department with Kussmaul respirations, fruity-smelling breath, and altered mental status. Blood glucose is 450 mg/dL, arterial pH 7.18, HCO₃⁻ 12 mEq/L, and serum ketones are strongly positive. What is the most common precipitating cause of diabetic ketoacidosis in this patient?

A 62-year-old woman with type 2 diabetes mellitus on metformin and glibenclamide presents with a 5-day history of progressive confusion, weakness, and polyuria. On examination, she is drowsy, respiratory rate 16/min (not labored), blood pressure 95/60 mmHg, and heart rate 112/min. Capillary blood glucose is 680 mg/dL. Arterial blood gas shows pH 7.32, HCO₃⁻ 18 mEq/L, and PaCO₂ 38 mmHg. Serum osmolality is 335 mOsm/kg. Serum sodium is 125 mEq/L (corrected). Urine ketones are negative. What is the most appropriate immediate next step in management?

A 28-year-old man with type 1 diabetes presents to the emergency department with severe hyperglycemia (680 mg/dL), pH 7.28, HCO₃⁻ 12 mEq/L, and prominent Kussmaul respiration. His serum osmolality is 315 mOsm/kg. A 35-year-old woman with undiagnosed diabetes presents with glucose 1100 mg/dL, pH 7.35, HCO₃⁻ 20 mEq/L, and no respiratory distress. Her serum osmolality is 340 mOsm/kg and she is drowsy. Which finding most reliably distinguishes the first patient's diagnosis (DKA) from the second patient's diagnosis (HHS)?

In diabetic ketoacidosis, which of the following best explains why serum sodium is typically LOW despite total body sodium depletion?

Which of the following is the PRIMARY mechanism of hyperglycemia in hyperglycemic hyperosmolar state (HHS) compared to diabetic ketoacidosis (DKA)?