Positive glucose on a urine dipstick in animals can occur in diabetes mellitus or what other state?

• A. Hypoglycemia
• B. Stress hyperglycemia
• C. Proteinuria
• D. Anemia

Answer: (B)

Glycosuria occurs when the amount of glucose filtered by the kidneys exceeds what the proximal tubules can reabsorb. The kidneys normally reclaim almost all filtered glucose, but once blood glucose rises above the renal threshold, glucose spills into the urine. This explains glucose detected on a urine dipstick in two situations: when there is true diabetes mellitus with chronic hyperglycemia, and when there is a transient spike in blood glucose during stress or acute illness, known as stress hyperglycemia. In stress hyperglycemia, hormones like cortisol and catecholamines increase hepatic glucose production and reduce insulin sensitivity, pushing blood glucose high enough to overwhelm tubular reabsorption and cause glycosuria, even in animals that are not diabetic.

The other options don’t fit because hypoglycemia lowers blood glucose and would not cause glucose to appear in urine; proteinuria reflects protein leakage in urine, not glucose; and anemia involves red blood cells and has no direct link to glucose in the urine.