Which symptom most clearly indicates hyperglycemia in a person with diabetes?

• A. Thirst
• B. Headache
• C. Nervousness
• D. Fruity breath odor

Answer: (A)

The main idea is that high blood glucose directly drives thirst through a process called osmotic diuresis. When glucose levels are elevated, the kidneys work to excrete the excess glucose into the urine. Glucose in the urine pulls water with it, causing more urination (polyuria). The body then becomes dehydrated, which triggers the sensation of thirst.

This makes thirst the most clear and direct signal of hyperglycemia in diabetes. Headache can occur with dehydration or high glucose but isn’t specific to high glucose alone. Nervousness is more typical of low blood sugar (hypoglycemia). Fruity breath odor points to ketosis, such as diabetic ketoacidosis, which is a serious complication that accompanies hyperglycemia but is not the straightforward symptom of elevated glucose itself.