A two year old child presents with persistent diarrhoea acidic stools and presence of one per cent of reducing substance in the fresh stools. What is the most probable diagnosis ?
**Core Concept**
The question is testing the understanding of carbohydrate malabsorption, specifically focusing on the clinical presentation and diagnostic clues for **lactose intolerance** or other malabsorptive conditions. The presence of reducing substances in stool is a key indicator of malabsorbed carbohydrates.
**Why the Correct Answer is Right**
Given the symptoms of persistent diarrhea, acidic stools, and the presence of reducing substances in the stool, the most likely diagnosis is a condition where the body is unable to properly absorb certain carbohydrates, leading to their presence in the stool. This scenario is highly suggestive of **lactose intolerance** or a similar malabsorptive condition, where lactose (a reducing sugar) is not absorbed due to a deficiency of **lactase**, the enzyme responsible for lactose digestion.
**Why Each Wrong Option is Incorrect**
**Option A:** Would be incorrect if it suggested a condition not related to carbohydrate malabsorption.
**Option B:** Might be incorrect if it pointed towards a condition that does not typically present with reducing substances in the stool.
**Option C:** Could be incorrect if it represented a diagnosis that does not align with the symptoms of acidic stools and diarrhea.
**Option D:** Assuming it's not the correct answer, would be incorrect based on the clinical presentation provided.
**Clinical Pearl / High-Yield Fact**
A key point to remember is that the presence of **reducing substances** in the stool, as indicated by a positive test for reducing sugars, is a critical diagnostic clue for carbohydrate malabsorption. This is particularly relevant in pediatric patients presenting with chronic diarrhea.
**Correct Answer:** D. Lactose intolerance