In the management of diabetic ketoacidosis during insulin therapy, which statement is incorrect?

• A. Potassium levels must be monitored closely.
• B. Sodium levels change with hyperglycemia.
• C. Serum osmolality remains unchanged.
• D. Insulin therapy requires careful fluid management.

Answer: (C)

During insulin therapy in diabetic ketoacidosis, serum osmolality changes rather than staying fixed. Hyperglycemia raises osmolality, and as insulin lowers glucose (and ketones are cleared) the osmolality tends to decrease toward normal. Fluid management further influences osmolality, since the type and rate of IV fluids alter solute concentration. So the statement that serum osmolality remains unchanged is not correct. In this setting, you also monitor potassium closely because insulin drives potassium into cells, and sodium appears low due to hyperglycemia, requiring correction to judge true Na status, all while carefully guiding fluids to restore perfusion and avoid rapid osmolar shifts.