A two year old child presents with persistent diarrhaea 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 tests the understanding of **carbohydrate malabsorption** disorders, specifically focusing on the clinical presentation and diagnostic clues of such conditions in pediatric patients. 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** (indicating malabsorbed carbohydrates), the most likely diagnosis is related to an inability to properly digest carbohydrates. This scenario is highly suggestive of **lactose intolerance** or a similar **disaccharidase deficiency**, where the body lacks the enzymes needed to break down certain sugars, leading to their malabsorption and subsequent fermentation by colonic bacteria, resulting in acidic stools.
**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 doesn't typically present with reducing substances in the stool.
**Option C:** Could be incorrect if it represented a diagnosis that doesn't align with the symptoms of acidic stools and diarrhea due to carbohydrate malabsorption.
**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 **Clinitest** or **Benedict's test**, is a critical clue pointing towards carbohydrate malabsorption. This is especially important in pediatric patients where such malabsorption can lead to significant morbidity.
**Correct Answer:** D. Carbohydrate malabsorption.