A 35-year-old woman comes to the office due to abdominal bloating and increased flatulence over the past 2 months. She works in a bank and says her job is very stressful and the flatulence has caused her embarrassment. The patient also reports bulky, loose stools and watery diarrhea 3 or 4 times a week. She has had no abdominal pain, blood in the stool, or melena. The patient lost 45 kg (100 lb) after undergoing Roux-en-Y gastric bypass surgery 3 years ago, but her weight has been stable over the past year. Other medical issues include type 2 diabetes mellitus and chronic anxiety. Current medications include metformin, sertraline, and multivitamin and mineral supplements. The patient does not use tobacco, alcohol, or illicit drugs.
Blood pressure is 134/67 mm Hg and pulse is 72/min. BMI is 36 kg/m². On physical examination, the abdomen is soft and nontender. Stool testing is negative for occult blood.
Laboratory results are as follows:
Which of the following is the most likely cause of this patient's gastrointestinal symptoms?

Question

A 35-year-old woman comes to the office due to abdominal bloating and increased flatulence over the past 2 months. She works in a bank and says her job is very stressful and the flatulence has caused her embarrassment. The patient also reports bulky, loose stools and watery diarrhea 3 or 4 times a week. She has had no abdominal pain, blood in the stool, or melena. The patient lost 45 kg (100 lb) after undergoing Roux-en-Y gastric bypass surgery 3 years ago, but her weight has been stable over the past year. Other medical issues include type 2 diabetes mellitus and chronic anxiety. Current medications include metformin, sertraline, and multivitamin and mineral supplements. The patient does not use tobacco, alcohol, or illicit drugs.
Blood pressure is 134/67 mm Hg and pulse is 72/min. BMI is 36 kg/m². On physical examination, the abdomen is soft and nontender. Stool testing is negative for occult blood.
Laboratory results are as follows:

Which of the following is the most likely cause of this patient's gastrointestinal symptoms?

Quizplus · Accepted Answer

11ec193a_9805_897d_853d_43954abd8d57_MD0002_00 This patient has bloating, flatulence, diarrhea, and macrocytic anemia, which, given her history of Roux-en-Y gastric bypass, should raise suspicion for small intestinal bacterial overgrowth (SIBO). SIBO is common in patients who have undergone gastrointestinal bypass surgery as the procedure forms a blind loop of intestine, allowing for excessive bacterial growth. SIBO usually presents with abdominal distension and discomfort, flatulence, and diarrhea. Severe or prolonged disease can cause fat malabsorption leading to steatorrhea, weight loss, and nutritional deficiencies (ie, vitamins A, D, B₁, B₁₂). Macrocytic anemia from vitamin B₁₂ deficiency is a common laboratory finding. ₁ ₁₂ ₁₂ The diagnosis of SIBO is made with a positive hydrogen breath test or jejunal aspiration and culture with high levels of bacterial colonization. Most patients are treated with antibiotics (eg, rifaximin). Recurrence is common and is typically treated with a second course of antibiotics. (Choice A) Celiac disease can cause steatorrhea, abdominal discomfort, and flatulence. However, patients typically develop a microcytic anemia due to iron deficiency, and the occurrence of symptoms after a gastric bypass procedure makes SIBO more likely. (Choice B) Inflammatory bowel disease can cause diarrhea, weight loss, and anemia, but patients often experience hematochezia and may have extraintestinal manifestations (eg, skin, ophthalmic, joint). Inflammatory markers (eg, C-reactive protein, erythrocyte sedimentation rate) are usually elevated. This patient's negative stool occult blood, normal C-reactive protein, and stable weight after her bypass make this diagnosis unlikely. (Choice C) Irritable bowel syndrome is characterized by chronic abdominal pain that improves with bowel movements, altered bowel habits, and a feeling of incomplete evacuation. Anemia and nutritional deficiencies suggest an alternate diagnosis. (Choice D) Microscopic colitis causes diarrhea and pain, but patients are generally older (age ≥50) and typically develop watery diarrhea (5-10 episodes per day) rather than large, bulky stools and flatulence. In addition, inflammatory markers are elevated in ≥50% of patients. Educational objective: Small intestinal bacterial overgrowth is a common complication of gastrointestinal bypass surgery. It presents with abdominal distension and discomfort, flatulence, diarrhea, and nutritional deficiencies. Diagnosis is made with a positive hydrogen breath test or jejunal aspiration and culture with high levels of bacterial colonization. __________ References: Nutritional deficiencies after bariatric surgery. (http://www.ncbi.nlm.nih.gov/pubmed/22525731) Consequences of small intestinal bacterial overgrowth in obese patients before and after bariatric surgery. (http://www.ncbi.nlm.nih.gov/pubmed/27576576)

A 35-Year-Old Woman Comes to the Office Due to Abdominal