A patient presents with polyuria, polydipsia, and polyphagia. What condition should you suspect?

A patient presents with polyuria, polydipsia, and polyphagia. What condition should you suspect?

• A. Hypothyroidism
• B. Diabetes mellitus
• C. Hypertension
• D. Anemia

Answer: (B)

The key idea is recognizing the triad that points to diabetes mellitus: polyuria, polydipsia, and polyphagia. When blood glucose is elevated, the kidneys can't reabsorb it all, so glucose spills into the urine (glucosuria) and pulls water with it, leading to more urination. The loss of fluids triggers increased thirst, hence polydipsia. Meanwhile, cells aren’t getting usable glucose due to insulin deficiency or resistance, so despite high blood glucose, the body feels "hungry," driving polyphagia. This combination is a classic pattern for diabetes mellitus and isn’t typical of hypothyroidism (which tends to cause fatigue and weight changes without osmotic diuresis), hypertension (high blood pressure without this triad), or anemia (fatigue or pallor, not marked polyuria/polydipsia).

The key idea is recognizing the triad that points to diabetes mellitus: polyuria, polydipsia, and polyphagia. When blood glucose is elevated, the kidneys can't reabsorb it all, so glucose spills into the urine (glucosuria) and pulls water with it, leading to more urination. The loss of fluids triggers increased thirst, hence polydipsia. Meanwhile, cells aren’t getting usable glucose due to insulin deficiency or resistance, so despite high blood glucose, the body feels "hungry," driving polyphagia. This combination is a classic pattern for diabetes mellitus and isn’t typical of hypothyroidism (which tends to cause fatigue and weight changes without osmotic diuresis), hypertension (high blood pressure without this triad), or anemia (fatigue or pallor, not marked polyuria/polydipsia).