Which diagnosis is suggested by polyuria, polydipsia, weight loss, and Kussmaul respirations with anion gap metabolic acidosis?

• A. Hyperosmolar hyperglycemic state
• B. Lactic acidosis
• C. Diabetic ketoacidosis
• D. Hypoglycemia

Answer: (A)

These findings point to diabetic ketoacidosis. When insulin is deficient, the body cannot use glucose effectively and turns to fat breakdown, producing ketone bodies. Those ketones create an anion gap metabolic acidosis, and the acidosis triggers a compensatory rise in breathing, known as Kussmaul respiration. The excess glucose in the blood also spills into urine, pulling water with it and causing polyuria, which leads to dehydration and compensatory polydipsia. Weight loss occurs from the catabolic state as the body breaks down fat and muscle for energy.

Hyperosmolar hyperglycemic state can present with very high glucose and dehydration, but it usually has little to no acidosis and typically lacks the pronounced Kussmaul breathing seen with DKA. Lactic acidosis can cause anion gap acidosis as well, but the combination of polyuria, polydipsia, weight loss, and Kussmaul breathing with anion gap acidosis most strongly supports DKA. Hypoglycemia would not fit this profile, as it does not cause this pattern of polyuria and acidosis.