A 38-year-old man comes to the office with abdominal discomfort and loose stools over the past year. He has also lost 10 kg (22 lb) despite having a normal appetite. The patient eats a balanced diet that includes a variety of fruits and vegetables, meats, whole grains, and dairy products. He has had no international travel, works indoors as an office manager, and has no sick contacts. Medical history is insignificant and the patient takes no medications. The patient drinks alcohol socially and does not use tobacco. Vital signs and physical examination are normal. Serum chemistry panel, complete blood count, and thyroid function tests are normal. Which of the following is the best next step for assessing for impaired nutrient absorption in this patient?

Question

A 38-year-old man comes to the office with abdominal discomfort and loose stools over the past year.  He has also lost 10 kg (22 lb) despite having a normal appetite.  The patient eats a balanced diet that includes a variety of fruits and vegetables, meats, whole grains, and dairy products.  He has had no international travel, works indoors as an office manager, and has no sick contacts.  Medical history is insignificant and the patient takes no medications.  The patient drinks alcohol socially and does not use tobacco.  Vital signs and physical examination are normal.  Serum chemistry panel, complete blood count, and thyroid function tests are normal.  Which of the following is the best next step for assessing for impaired nutrient absorption in this patient?

Quizplus · Accepted Answer

Impaired intestinal absorption of nutrients is called malabsorption. Significant malabsorption may present with diarrhea and steatorrhea (bulky, foul-smelling stools; visible oil droplets; greasy toilet ring), but more often patients have nonspecific symptoms such as weight loss, fatigue, or vague abdominal discomfort. Patients may also have characteristic findings due to specific nutrient deficiencies. Generalized malabsorption is commonly due to defects in pancreatic secretion (eg, chronic pancreatitis, cystic fibrosis), mucosal disorders (eg, celiac disease, inflammatory bowel disease), bacterial overgrowth (eg, gastrointestinal surgery, abnormal motility), or parasitic diseases (eg, Giardia). Dietary lipids are the macronutrient with the most complex digestive pathway. Fats are typically the earliest and most severely affected nutrient in generalized malabsorption, and testing for fat malabsorption is therefore the most sensitive strategy for screening for malabsorptive disorders. A qualitative assay of stool with Sudan III stain can quickly and easily identify unabsorbed fat and confirm malabsorption. (Stool should normally contain no measurable fat.) (Choices A, B, C, and D) Abdominal imaging can be used to identify thickening of the bowel wall due to inflammation or structural disorders of the pancreas (eg, chronic pancreatitis). Endoscopy with jejunal biopsy can diagnose celiac disease, and colonoscopy can identify inflammatory bowel disease. Stool inspection for ova and parasites can identify infectious causes of malabsorption such as Giardia and Cryptosporidium. Although these tests are useful for determining specific causes of generalized malabsorption, fecal fat testing is a less invasive and more sensitive test for confirming malabsorption of any etiology. (Choice F) Iron and vitamin B₁₂ deficiency occur commonly in patients with malabsorption. However, vitamin B₁₂ levels have a low sensitivity for malabsorption; deficiency develops only after years and is more common with specific etiologies (eg, pernicious anemia). In addition, this patient's normal complete blood count makes vitamin B₁₂ deficiency less likely. Educational objective: Malabsorption is a syndrome of impaired intestinal digestion and absorption. Fats are typically the most severely affected macronutrient in generalized malabsorption, and testing the stool for fat (eg, with Sudan III stain) is the most sensitive strategy for screening for malabsorptive disorders.

A 38-Year-Old Man Comes to the Office with Abdominal Discomfort