malabsorption
Jump to navigation
Jump to search
Introduction
Imperfect, inadequate, or otherwise disordered gastrointestinal absorption.
Etiology
- malabsorption syndromes
- exocrine pancreatic insufficiency
- bile salt deficiency
- cholestasis
- bacterial deconjugation, blind loop syndrome
- surgical
- gastric bypass
- short bowel syndrome (< 200 cm small bowel)
- small intestinal parasites
- impaired lymphatic drainage
- pharmacologic causes:
Pathology
- altered intraluminal digestion of complex molecules by pancreatic enzymes
- altered solubilization of fats by bile salts in mixed micelles
- altered cellular uptake of amino acids, oligopeptides & monosaccharides by carrier-specific transporters
- altered delivery of nutrients to the systemic circulation
Clinical manifestations
- may be asymptomatic
- diarrhea*
- often bulky, oily & foul-smelling stools
- steatorrhea
- weight loss*
- evidence of nutritional deficiencies
* when diarrhea from malabsorption leads to diminished calorie intake, diminished calorie intake is the said cause of weight loss[5]
Laboratory
- complete blood count (CBC) & iron studies:
- iron deficiency may be presenting sign
- macrocytic anemia may occur with folate deficiency or vitamin B12 deficiency
- stool studies in 100 g/day fat diet
- stool weight (normal < 200 g/day in USA)
- fat content (normal < 7 g/day in USA)
- D-xylose absorption studies or ratio of mannitol/ lactulose absorption
- small bowel biopsy
- secretin test to assess pancreatic insufficiency
- prolonged prothrombin time (PT) may reflect vitamin K deficiency
- Schilling test
- see ARUP consult[4]
Diagnostic procedures
Radiology
- barium contrast small bowel study study, including examination of the ileum to identify strictures, blind loops, fistulas, diverticula, or extent of previous surgical resection
Management
- trial of eliminating potential offending agent(s) prior to workup[1]
- empiric antibiotics for suspected bacterial overgrowth
- pancreatic insufficiency often responds to pancrelipase
More general terms
More specific terms
Additional terms
References
- ↑ 1.0 1.1 1.2 Medical Knowledge Self Assessment Program (MKSAP) 11, 14, 15, 17. American College of Physicians, Philadelphia 1998, 2006, 2009, 2015
- ↑ Harrison's Principles of Internal Medicine, 13th ed. Companion Handbook, Isselbacher et al (eds), McGraw-Hill Inc. NY, 1995, pg 829-39
- ↑ Harrison's Online, Chapter 286, McGraw-Hill, 2003
- ↑ 4.0 4.1 ARUP Consult: Malabsorption The Physician's Guide to Laboratory Test Selection & Interpretation https://www.arupconsult.com/content/malabsorption
- ↑ 5.0 5.1 Geriatric Review Syllabus, 11th edition (GRS11) Harper GM, Lyons WL, Potter JF (eds) American Geriatrics Society, 2022