A 14-year-old Caucasian boy is brought to the physician by his mother due to chronic diarrhea and failure to gain weight appropriately. He has a history of recurrent respiratory infections, and prior sputum cultures have been positive for Pseudomonas aeruginosa. His younger brother died from a severe respiratory infection at age 9. Which of the following agents is most likely to improve this patient's condition in the long term?

Question

A 14-year-old Caucasian boy is brought to the physician by his mother due to chronic diarrhea and failure to gain weight appropriately.  He has a history of recurrent respiratory infections, and prior sputum cultures have been positive for Pseudomonas aeruginosa.  His younger brother died from a severe respiratory infection at age 9.  Which of the following agents is most likely to improve this patient's condition in the long term?

Quizplus · Accepted Answer

11ec160b_3bcd_d8ff_9249_7be21bd3930c_MD0001_00 This young Caucasian patient has a history of recurrent respiratory infections caused by Pseudomonas aeruginosa, chronic diarrhea, and failure to thrive. These findings, along with a family history of early sibling death from pulmonary infection, suggest a diagnosis of cystic fibrosis. Steatorrhea and failure to thrive occur as a result of malabsorption due to obstructive fibrosis and progressive insufficiency of the exocrine pancreas. Pancreatic lipase supplementation is likely to improve this patient's condition by enhancing macronutrient and vitamin absorption. (Choice A) Agents that decrease gastrointestinal motility (eg, opiates such as loperamide) can help decrease the volume of diarrhea by slowing intestinal transit time and allowing greater net fluid resorption. However, antimotility agents would not improve the deficiencies in nutrient absorption. (Choice B) A gluten-free diet is the mainstay of treatment for celiac sprue but would be unlikely to help this patient's malabsorption. (Choice C) Metronidazole is effective only for diarrhea due to infectious causes (eg, giardiasis). This patient's diarrhea is more likely due to malabsorption secondary to cystic fibrosis. (Choice D) Octreotide is a somatostatin analogue that decreases gut motility, blood flow, and endocrine and exocrine pancreatic function. Octreotide decreases secretion of pancreatic enzymes into the intestine and could therefore aggravate this patient's malabsorptive diarrhea and associated nutritional deficiencies. (Choice F) 5-aminosalicylates (eg, sulfasalazine, mesalamine) are used to treat inflammatory bowel diseases such as Crohn's disease and ulcerative colitis. They work by inhibiting cytokine, prostaglandin, and leukotriene synthesis during inflammation. This patient's diarrhea and weight loss are not caused by inflammation. Educational objective: In a young Caucasian patient, the combination of recurrent respiratory infections with Pseudomonas aeruginosa, diarrhea, and failure to thrive suggests a diagnosis of cystic fibrosis. Cystic fibrosis causes steatorrhea and failure to thrive due to malabsorption secondary to pancreatic insufficiency, which can be corrected by pancreatic enzyme supplementation.

A 14-Year-Old Caucasian Boy Is Brought to the Physician by His