A 19-year-old man has a long history of weight loss, abdominal distention, bloating, and diarrhea. Investigation reveals steatorrhea, and a small bowel biopsy reveals blunting and flattening of villi.
**Core Concept**
The patient's symptoms and biopsy results suggest a malabsorptive disorder characterized by impaired small bowel function, leading to steatorrhea (excess fat in the stool) and malnutrition. This condition is often associated with a deficiency in pancreatic enzymes, which are essential for fat and protein digestion.
**Why the Correct Answer is Right**
The patient's symptoms and biopsy findings are consistent with celiac disease, an autoimmune disorder triggered by gluten ingestion. In celiac disease, the immune response to gluten leads to inflammation and damage to the small intestinal mucosa, resulting in villous atrophy (blunting and flattening of villi). This impairs the absorption of nutrients, including fats, proteins, and carbohydrates. The presence of steatorrhea indicates malabsorption of fats, which is a hallmark of celiac disease.
**Why Each Wrong Option is Incorrect**
**Option A:** Crohn's disease is a type of inflammatory bowel disease (IBD) that can affect any part of the gastrointestinal tract, but it typically presents with more severe symptoms, such as bloody diarrhea, weight loss, and abdominal pain. While Crohn's disease can cause malabsorption, the biopsy findings in this case are more characteristic of celiac disease.
**Option B:** Irritable bowel syndrome (IBS) is a functional gastrointestinal disorder characterized by chronic abdominal pain, bloating, and altered bowel habits. However, IBS does not typically cause steatorrhea or villous atrophy.
**Option C:** Lactose intolerance is a condition where the small intestine does not produce enough lactase enzyme to digest lactose, a sugar found in milk. While lactose intolerance can cause bloating and diarrhea, it does not typically lead to villous atrophy or steatorrhea.
**Option D:** Whipple's disease is a rare bacterial infection that affects the small intestine and can cause malabsorption, weight loss, and diarrhea. However, it is typically associated with more severe symptoms, such as fever, joint pain, and neurological manifestations.
**Clinical Pearl / High-Yield Fact**
Celiac disease is often associated with other autoimmune disorders, such as type 1 diabetes, thyroid disease, and rheumatoid arthritis. Screening for celiac disease is recommended in patients with these conditions, especially if they have gastrointestinal symptoms.
**Correct Answer: C. Crohn's disease is a type of inflammatory bowel disease (IBD) that can affect any part of the gastrointestinal tract, but it typically presents with more severe symptoms, such as bloody diarrhea, weight loss, and abdominal pain. While Crohn's disease can cause malabsorption, the biopsy findings in this case are more characteristic of celiac disease.