A routine urinalysis on a young child with diarrhea shows negative glucose but positive ketones. Which explanation is most likely?

A routine urinalysis on a young child with diarrhea shows negative glucose but positive ketones. Which explanation is most likely?

• A. The child has type 1 diabetes mellitus
• B. The child is suffering from lactic acidosis, and lactic acid interferes with the ketone test
• C. Increased catabolism of fat due to decreased intestinal absorption
• D. The ketone test was read after the maximum allowed time

Answer: (C)

Ketone bodies appear in urine when the body has limited carbohydrate supply and must rely on fat breakdown for energy. In a young child with diarrhea, nutrient absorption is reduced and intake may be limited, creating a fasting-like state. The liver converts fatty acids into ketone bodies (acetoacetate and beta-hydroxybutyrate), which are excreted in urine, leading to ketonuria even without high blood glucose. A negative glucose result helps rule out diabetes mellitus as the cause of ketosis, making increased fat catabolism from malabsorption the most likely explanation. The other options aren’t as consistent with a fasting/starvation-like ketosis in a diarrheal child.

Ketone bodies appear in urine when the body has limited carbohydrate supply and must rely on fat breakdown for energy. In a young child with diarrhea, nutrient absorption is reduced and intake may be limited, creating a fasting-like state. The liver converts fatty acids into ketone bodies (acetoacetate and beta-hydroxybutyrate), which are excreted in urine, leading to ketonuria even without high blood glucose. A negative glucose result helps rule out diabetes mellitus as the cause of ketosis, making increased fat catabolism from malabsorption the most likely explanation. The other options aren’t as consistent with a fasting/starvation-like ketosis in a diarrheal child.