In which of the following conditions of malabsorption, an intestinal biopsy is diagnostic –
**Core Concept**
The question is testing the ability to identify conditions where an intestinal biopsy is diagnostic for malabsorption. Intestinal biopsy is a critical tool for diagnosing various forms of malabsorption by providing histopathological evidence of mucosal damage or dysfunction.
**Why the Correct Answer is Right**
The correct answer is **Celiac disease**, a chronic autoimmune disorder caused by the ingestion of gluten in genetically predisposed individuals. Intestinal biopsy in celiac disease typically shows villous atrophy, crypt hyperplasia, and increased intraepithelial lymphocytes. This histological pattern is diagnostic and is essential for distinguishing celiac disease from other forms of malabsorption.
**Why Each Wrong Option is Incorrect**
**Option A:** Whipple's disease is a rare bacterial infection caused by *Tropheryma whipplei*, which can lead to malabsorption. However, the diagnosis of Whipple's disease is typically made by identifying the bacteria on a small intestinal biopsy or by demonstrating the presence of the bacteria in the stool or tissue samples using molecular techniques.
**Option B:** Chronic pancreatitis can lead to malabsorption due to pancreatic enzyme insufficiency. However, the diagnosis of chronic pancreatitis is typically made by imaging studies (e.g., CT or MRI) or by demonstrating pancreatic enzyme deficiency in the stool or blood.
**Option D:** Lactose intolerance is a common cause of malabsorption due to the inability to digest lactose, a sugar found in milk and other dairy products. However, the diagnosis of lactose intolerance is typically made by demonstrating the presence of lactose in the stool or by performing a hydrogen breath test.
**Clinical Pearl / High-Yield Fact**
Celiac disease is a classic example of a malabsorption syndrome where the diagnosis can be made by a single diagnostic test - the intestinal biopsy. This is because the histological changes in celiac disease are so characteristic that they are often considered diagnostic.
**Correct Answer: C. Celiac disease**