A patient with polyuria, polydipsia, and a random blood glucose of 450 mg/dL with ketones. What is the most likely diagnosis and initial management?

• A. Diabetic ketoacidosis; begin IV fluids, start insulin therapy, and correct electrolytes
• B. Hyperosmolar hyperglycemic state; begin IV fluids
• C. Hypoglycemia; administer glucose
• D. Lactic acidosis; treat underlying

Answer: (C)

This scenario is most consistent with diabetic ketoacidosis. The combination of marked hyperglycemia with ketones, plus polyuria and polydipsia, reflects absolute or near-absolute insulin deficiency with increased counterregulatory hormones driving lipolysis and ketogenesis, leading to metabolic acidosis and dehydration. This distinguishes it from hypoglycemia (low glucose) and from hyperosmolar hyperglycemic state (which usually has no significant ketosis and occurs with even higher glucose levels).

Initial management aims to restore水 volume, halt ketogenesis, and correct electrolyte disturbances. The first step is aggressive IV fluids with isotonic saline to correct dehydration and improve perfusion. After volume resuscitation, begin insulin therapy to shut down ketone production and reduce blood glucose. Crucially, monitor and correct potassium because total body potassium is depleted even if serum potassium is normal or high at presentation; if potassium is low, potassium replacement comes before or with insulin (and if very low, insulin is withheld until potassium is safely raised). As glucose nears 200–250 mg/dL, switch to IV fluids with dextrose to avoid hypoglycemia while continuing insulin and electrolyte management. Address any precipitating factor (infection, inadequate insulin, etc.) and reassess electrolytes regularly, bicarbonate only if there is severe acidosis (very low pH).