A 25-year-old woman comes to the office due to 6 weeks of postprandial abdominal discomfort, flatulence, and nausea. The patient has tried both omeprazole and fiber supplementation without improvement of her symptoms. Although her bowel movements are currently regular, she had an acute diarrheal illness 2 months ago that resolved spontaneously. The patient has no vomiting, fever, bloody stools, early satiety, trouble swallowing, or unexpected weight loss. She has had no sick contacts, and her family history is insignificant. The patient does not use tobacco, alcohol, or illicit drugs. Temperature is 37.4 C (99.3 F), blood pressure is 120/80 mm Hg, and pulse is 80/min. She is well-appearing. Mucous membranes are moist, and cardiopulmonary examination is normal. The abdomen is moderately distended but nontender with no rebound or guarding. Complete blood count and serum electrolytes are within normal limits. Which of the following is the best next step in management of this patient?

Question

A 25-year-old woman comes to the office due to 6 weeks of postprandial abdominal discomfort, flatulence, and nausea.  The patient has tried both omeprazole and fiber supplementation without improvement of her symptoms.  Although her bowel movements are currently regular, she had an acute diarrheal illness 2 months ago that resolved spontaneously.  The patient has no vomiting, fever, bloody stools, early satiety, trouble swallowing, or unexpected weight loss.  She has had no sick contacts, and her family history is insignificant.  The patient does not use tobacco, alcohol, or illicit drugs.  Temperature is 37.4 C (99.3 F), blood pressure is 120/80 mm Hg, and pulse is 80/min.  She is well-appearing.  Mucous membranes are moist, and cardiopulmonary examination is normal.  The abdomen is moderately distended but nontender with no rebound or guarding.  Complete blood count and serum electrolytes are within normal limits.  Which of the following is the best next step in management of this patient?

Quizplus · Accepted Answer

11ec25c8_d223_0507_bc81_35b0e98379e7_MD0003_00 This patient likely has lactose intolerance (LI), presenting with postprandial gastrointestinal distress (eg, abdominal pain, bloating), benign abdominal examination, and normal laboratory studies. LI is caused by deficiency of intestinal lactase, an enzyme in the brush border that metabolizes dietary lactose. Undigested lactose is metabolized by colonic bacteria, releasing hydrogen gas and other byproducts. The prevalence of LI is higher in patients who are not Caucasian (eg, Asian, African). It may be precipitated by inflammatory disorders affecting the brush border, such as infectious gastroenteritis (as is likely in this patient who had a recent intestinal illness), celiac disease, and Crohn disease. The symptoms of LI in adults are often nonspecific and may vary with underlying visceral hypersensitivity. Diarrhea is typically not prominent. The relation to lactose intake may not be readily apparent because a broad variety of foods contain lactose; clarification may require a dedicated trial of dietary lactose exclusion. Lactose breath testing, which detects hydrogen released from a standardized dose of oral lactose, can be diagnostic. (Choice A) Stool cultures can diagnose bacterial gastroenteritis and are indicated in severe acute diarrhea (eg, hypovolemia, hematochezia, fever). They are not required in this individual since her diarrhea has resolved. (Choices B and C) Esophagogastroduodenoscopy is indicated to evaluate upper gastrointestinal symptoms associated with features suggesting bleeding (eg, iron deficiency anemia) or malignancy (eg, progressive dysphagia, odynophagia). Likewise, colonoscopy is indicated for lower gastrointestinal symptoms associated with bleeding (eg, hematochezia) or risk factors for malignancy (eg, age >50, unexpected weight loss). This young patient has no alarm features, and invasive studies should be deferred. (Choice E) Rifaximin is indicated for small intestinal bacterial overgrowth (SIBO), which causes bloating and diarrhea in susceptible patients (eg, intestinal surgery, scleroderma). SIBO is unlikely in a patient with regular bowel movements and no relevant risk factors. (Choice F) Tricyclic antidepressants (TCAs) (eg, amitriptyline) are sometimes used to treat functional gastrointestinal disorders (eg, irritable bowel syndrome). Although this patient's symptoms resemble a functional bowel disorder, TCAs have significant potential adverse effects, and LI should be ruled out first. Educational objective: Lactose intolerance is caused by deficiency of intestinal lactase and presents with postprandial abdominal pain, bloating, and nausea. It may be precipitated by inflammatory disorders that affect the intestinal brush border (eg, infectious gastroenteritis, celiac disease, Crohn disease). Lactose breath testing, which detects hydrogen released from a standardized dose of oral lactose, can be diagnostic.

A 25-Year-Old Woman Comes to the Office Due to 6