A 23-year-old man comes to the office due to frequent, foul-smelling, bulky stools and weight loss over the last 6 months. He has lost about 4.5 kg (10 lb) over the past 3 months. He also has poor energy and occasional joint pains. The patient has no previous medical problems and takes no medication. He does not use tobacco, alcohol, or illicit drugs. Vital signs are normal. Examination shows mild pallor. There is no hepatosplenomegaly or lymphadenopathy. Hemoglobin is 10.2 g/dL and serum ferritin is 10 ng/mL. Immunoglobulin A anti-tissue transglutaminase antibody screening is negative. Small-bowel biopsy shows villous atrophy. Which of the following is the most likely cause of this patient's symptoms?

Question

A 23-year-old man comes to the office due to frequent, foul-smelling, bulky stools and weight loss over the last 6 months.  He has lost about 4.5 kg (10 lb) over the past 3 months.  He also has poor energy and occasional joint pains.  The patient has no previous medical problems and takes no medication.  He does not use tobacco, alcohol, or illicit drugs.  Vital signs are normal.  Examination shows mild pallor.  There is no hepatosplenomegaly or lymphadenopathy.  Hemoglobin is 10.2 g/dL and serum ferritin is 10 ng/mL.  Immunoglobulin A anti-tissue transglutaminase antibody screening is negative.  Small-bowel biopsy shows villous atrophy.  Which of the following is the most likely cause of this patient's symptoms?

Quizplus · Accepted Answer

11ec25c8_d26b_ce3a_bc81_51779cbec225_MD0003_00 This patient's clinical presentation is highly suggestive of celiac disease, with multiple features of malabsorption (frequent, foul-smelly stools), characteristic abnormalities on biopsy of the small bowel (eg, villous atrophy), and symptoms associated with celiac disease (eg, poor energy, joint pains). The diagnosis of celiac disease is highly correlated with positive results on serological studies, primarily IgA anti-tissue transglutaminase and IgA anti-endomysial antibodies. However, many patients with biopsy-confirmed celiac disease (as in this case) will have negative results on IgA antibody testing due to an associated selective IgA deficiency, which is common in celiac disease. If IgA serology is negative but the suspicion for celiac disease is high, total IgA should be measured (or IgG-based serologic testing should be done). (Choice A) Aplastic anemia is an uncommon cause of anemia. In addition to symptoms of a low red cell count, patients with aplastic anemia may develop bleeding (due to thrombocytopenia) and infection (due to leukopenia). Malabsorption is not a characteristic of aplastic anemia, and ferritin is usually normal. (Choice C) Collagenous colitis is an uncommon disorder producing chronic watery diarrhea. The colon is frequently involved, but colonoscopy shows normal mucosa. Biopsy shows mucosal subepithelial collagen deposition. (Choice D) This patient has a number of features, including fatigue, diarrhea, and weight loss, that could be consistent with Crohn's disease. Malabsorption is less common in Crohn's disease and is usually due to multiple bowel resections. Patients with the disease will show inflammatory signs on biopsy rather than the typical features of villous atrophy seen in this patient. (Choice E) Irritable bowel syndrome is a chronic disorder characterized by distressing gastrointestinal symptoms such as diarrhea, constipation, pain, and bloating. Biopsy results are normal in irritable bowel syndrome, and features of malabsorption should prompt a search for an alternate explanation. (Choice F) Lactose intolerance is a common cause of diet-related diarrhea. Symptoms are due to impaired digestion and absorption of lactose with resulting delivery of a sugar load to the colon. Malabsorption of other nutrients, however, is not typical. Educational objective: Celiac disease should be suspected in any patient with malabsorption and iron deficiency anemia. IgA anti-endomysial and anti-tissue transglutaminase antibodies are highly predictive of celiac disease but may be absent if there is concurrent selective IgA deficiency. References: Hematologic manifestations of celiac disease. (http://www.ncbi.nlm.nih.gov/pubmed/16973955)

A 23-Year-Old Man Comes to the Office Due to Frequent