A 35-year-old man comes to the office due to bloating, excessive flatus, and loose stools since an episode of food poisoning several months ago. The patient had been on a cruise ship when he developed nausea, vomiting, and diarrhea. Several other patrons developed similar symptoms that resolved with supportive care only. The patient's current symptoms began 1-2 weeks after returning home and usually occur in the morning shortly after breakfast. His usual breakfast consists of coffee with whole milk and cereal or oatmeal. Soon after eating, he develops bloating followed by crampy abdominal pain and loose stools. The symptoms occasionally recur after dinner. Medical history is insignificant. The patient drinks 1 or 2 beers on weekends and does not use tobacco or illicit drugs. He reports no other recent travel outside the country or unusual food exposures.
Vital signs are normal. The abdomen is soft and nontender. Bowel sounds are present with loud borborygmi. There is no hepatomegaly or splenomegaly. Stool occult blood testing is negative.
Complete blood count, serum chemistries, TSH, erythrocyte sedimentation rate, and HIV serology are within normal limits.
Which of the following is the best next step in management of this patient?

Question

A 35-year-old man comes to the office due to bloating, excessive flatus, and loose stools since an episode of food poisoning several months ago.  The patient had been on a cruise ship when he developed nausea, vomiting, and diarrhea.  Several other patrons developed similar symptoms that resolved with supportive care only.  The patient's current symptoms began 1-2 weeks after returning home and usually occur in the morning shortly after breakfast.  His usual breakfast consists of coffee with whole milk and cereal or oatmeal.  Soon after eating, he develops bloating followed by crampy abdominal pain and loose stools.  The symptoms occasionally recur after dinner.  Medical history is insignificant.  The patient drinks 1 or 2 beers on weekends and does not use tobacco or illicit drugs.  He reports no other recent travel outside the country or unusual food exposures.
Vital signs are normal.  The abdomen is soft and nontender.  Bowel sounds are present with loud borborygmi.  There is no hepatomegaly or splenomegaly.  Stool occult blood testing is negative.
Complete blood count, serum chemistries, TSH, erythrocyte sedimentation rate, and HIV serology are within normal limits.
Which of the following is the best next step in management of this patient?

Quizplus · Accepted Answer

This patient most likely has secondary lactose intolerance, which can develop after acute infection or inflammation (eg, viral gastroenteritis, Crohn disease flare-up). Lactose intolerance is characterized by crampy abdominal pain, bloating, increased flatulence, and diarrhea, which occur after ingestion of lactose-containing products. Frequently, the only examination finding is increased borborygmi (bowel sounds). Stool examination may reveal an elevated osmotic gap (>125 mOsm/kg) and decreased pH (<6). elevated osmotic gap Secondary lactose intolerance occurs due to inflammatory destruction of the terminal villi and subsequent loss of the lactase enzyme. Recovery of enzyme activity can occur, though it may take several months after the inflammatory insult ceases and healing begins. Management involves maintaining a lactose-restricted diet, enzyme replacement, and vitamin D and calcium supplementation. (Choice A) Stool microscopy is an important consideration in patients with acute-onset diarrhea, though it has a limited role in the evaluation of chronic diarrhea in high-income settings. One important consideration is giardiasis, which can result in secondary lactose intolerance; however, this patient has a convincing history for recent viral gastroenteritis and he lacks risk factors (eg, camping) and other key symptoms of chronic giardiasis (eg, weight loss, steatorrhea, malaise, fatigue). (Choice B) Fat malabsorption typically presents with pale, voluminous steatorrhea. Abdominal pain and increased flatulence are not common. (Choice C) Although empiric antibiotics may be considered for the treatment of acute diarrhea in certain circumstances (eg, severe symptoms), they do not have a major role in the management of undifferentiated chronic diarrhea. (Choice E) Irritable bowel syndrome, which may be treated by a diet low in fermentable oligo-, di-, and monosaccharides and polyols, also presents with chronic abdominal pain and diarrhea. However, patients typically do not relate symptoms of diarrhea to particular meals (eg, breakfast) and the abdominal pain is frequently related to defecation. Educational objective: Secondary lactose intolerance can develop after acute infection or inflammation and is characterized by crampy abdominal pain, bloating, increased flatulence, and diarrhea. Management involves a lactose-restricted diet, enzyme replacement, and vitamin D and calcium supplementation. Once the inciting insult resolves, recovery of lactose tolerance can occur over a period of months. __________ References: Lactose intolerance. (http://www.ncbi.nlm.nih.gov/pubmed/26715083) Lactose intolerance in adults: biological mechanism and dietary management. (http://www.ncbi.nlm.nih.gov/pubmed/26393648)

A 35-Year-Old Man Comes to the Office Due to Bloating