A 30-year-old man comes to the office due to a 4-month history of fatigue that is worse at the end of the day. The patient has also had abdominal bloating and intermittent loose stools after meals. His appetite is normal, and he has had no weight loss. Vital signs are normal. Examination shows pale mucosa. The abdomen is mildly distended and tympanic; there is no tenderness or organomegaly. Rectal examination reveals brown stool that is negative for fecal occult blood. Laboratory results are as follows: C-reactive protein level is normal. Which of the following pathologic gastrointestinal tract findings is most likely to be present in this patient?

Question

A 30-year-old man comes to the office due to a 4-month history of fatigue that is worse at the end of the day.  The patient has also had abdominal bloating and intermittent loose stools after meals.  His appetite is normal, and he has had no weight loss.  Vital signs are normal.  Examination shows pale mucosa.  The abdomen is mildly distended and tympanic; there is no tenderness or organomegaly.  Rectal examination reveals brown stool that is negative for fecal occult blood.  Laboratory results are as follows:  C-reactive protein level is normal.  Which of the following pathologic gastrointestinal tract findings is most likely to be present in this patient?

Quizplus · Accepted Answer

11ec160b_3ad8_2d89_9249_d7730b9ae30e_MD0001_00 This patient's loose stools, abdominal cramps, and microcytic anemia are most likely due to celiac disease, an immune-mediated disorder of the small bowel caused by dietary gluten. Gliadin, a component of gluten, is responsible for triggering the T-cell-mediated reaction against the small-bowel mucosa seen in celiac disease. This is initially characterized by intraepithelial lymphocytosis, followed as the disease progresses by a loss of small-bowel intestinal villi and mucosal atrophy. This decreases the nutritional absorptive capabilities of the small bowel, particularly in the duodenum and proximal jejunum. Because iron is absorbed primarily in the duodenum, iron deficiency leading to microcytic anemia is a common manifestation of celiac disease; common presenting features include fatigue and pale mucosa. Other symptoms of gluten-sensitive enteropathy include postprandial diarrhea and steatorrhea (eg, pale, loose stools), abdominal cramps, bloating, flatulence, and weight loss. Celiac disease is not associated with elevated systemic inflammatory markers (eg, C-reactive protein, erythrocyte sedimentation rate), and unlike gastrointestinal disorders that cause chronic blood loss (eg, inflammatory bowel disease, colon cancer), in celiac disease, fecal occult blood testing is negative. (Choice B) Pernicious anemia is characterized by antibody-mediated destruction of intrinsic factor and gastric parietal cells. This can lead to decreased vitamin B₁₂ absorption, with macrocytic (not microcytic) anemia, glossitis, and, sometimes, subacute combined degeneration of the dorsolateral spinal cord. (Choice C) Ulcerative colitis causes chronic inflammatory changes of the colonic mucosa and submucosa. Iron deficiency anemia is common but is due to blood loss rather than malabsorption; a positive fecal occult blood test would be expected, and inflammatory markers are typically elevated. (Choice D) Giardiasis is usually diagnosed on stool testing, although Giardia lamblia trophozoites are readily visible on small-bowel biopsy. Giardiasis is a common cause of diarrhea and may cause steatorrhea due to impairment of brush border enzymes. However, iron malabsorption with microcytic anemia is uncommon. (Choice E) Collagenous colitis is characterized by subepithelial collagen deposition in the colon. It often causes watery diarrhea but does not affect iron absorption in the small intestine, so microcytic anemia would be unexpected. Educational objective: Celiac disease is an immune-mediated disorder triggered by dietary gluten that causes small-bowel malabsorption. Because the proximal small bowel is primarily affected, iron deficiency leading to microcytic anemia is common. Histopathology is characterized by intraepithelial lymphocytosis, loss of intestinal villi, and mucosal atrophy.

A 30-Year-Old Man Comes to the Office Due to a 4-Month