eMedicine Specialties > Gastroenterology > Systemic Disease

Malabsorption: Differential Diagnoses & Workup

Author: Jan-Michael A Klapproth, MD, Assistant Professor, Department of Medicine, Division of Digestive Diseases, Emory University School of Medicine
Coauthor(s): Vincent W Yang, MD, PhD, R Bruce Logue Professor, Director, Division of Digestive Diseases, Department of Medicine, Professor of Hematology and Oncology, Winship Cancer Institute, Emory University School of Medicine
Contributor Information and Disclosures

Updated: Aug 14, 2008

Differential Diagnoses

Acrodermatitis Enteropathica
Cystic Fibrosis
Hartnup Disease
Intestinal Lymphangiectasia
Whipple Disease
Zollinger-Ellison Syndrome

Other Problems to Be Considered

Amino acid deficiencies (cystinuria)
Autoimmune enteropathy
Sucrose-isomaltase deficiency
Tropical jejunitis

Workup

Laboratory Studies

  • Hematological tests  
    • A CBC count may reveal microcytic anemia due to iron deficiency or macrocytic anemia due to vitamin B-12 or folate malabsorption.
    • Serum iron, vitamin B-12, and folate concentrations may help establish a diagnosis.
    • Prothrombin time may be prolonged because of malabsorption of vitamin K, a fat-soluble vitamin.
  • Electrolytes and chemistries  
    • Malabsorption can involve electrolyte imbalances, such as hypokalemia, hypocalcemia, hypomagnesemia, and metabolic acidosis.
    • Protein malabsorption may cause hypoproteinemia and hypoalbuminemia.
    • Fat malabsorption can lead to low serum levels of triglycerides, cholesterol, and alpha- and beta-carotene.
    • Westergren sedimentation rate is elevated in Crohn disease and Whipple disease.
  • Serology  
    • No serologic tests are specific for malabsorption.
    • Serum antigliadin and antiendomysial antibodies can be used to help diagnose celiac sprue.
    • Serum IgA can be used to rule out IgA deficiency.
    • Determination of fecal elastase and chymotrypsin (2 proteases produced by the pancreas) can be used to try to distinguish between pancreatic causes and intestinal causes of malabsorption.

Imaging Studies

  • Small bowel barium studies
    • An abnormal small bowel pattern obtained from barium studies of the upper gastrointestinal tract may reveal the nature of malabsorption.
    • The mucosa pattern associated with celiac disease often becomes obliterated or coarsened.
    • Flocculation of the barium occurs in the gut lumen.
    • Small bowel dilation and diverticulosis are frequently identified in scleroderma.
    • Regional enteritis of the small intestine can lead to stricture, ulceration, and fistula formation.
    • Other anatomical abnormalities, such as surgical changes or enterocolonic fistula, also can be detected on x-ray films.
  • CT scan of the abdomen: Performing this study may help detect evidence of chronic pancreatitis, such as pancreatic calcification or atrophy. Enlarged lymph nodes are seen in Whipple disease and lymphoma.
  • Endoscopic retrograde cholangiopancreatogram (ERCP): This study helps document malabsorption due to pancreatic or biliary-related disorders.
  • Plain abdominal x-ray film: Pancreatic calcifications are indicative of chronic pancreatitis.

Other Tests

  • Tests of fat malabsorption
    • This usually is the first test because many disease processes result in fat malabsorption.
    • For a quantitative measurement of fat absorption, a 72-hour fecal fat collection is often performed and is considered the criterion standard.
    • Qualitative tests include the acid steatocrit test and Sudan III stain of stool, but these tests are less reliable.
    • Instruct patients to consume a normal amount (80-100 g/d) of fat before and during the collection. Based on this intake, fecal fat excretion in healthy individuals should be less than 7 g/d.
  • D-xylose test
    • If the 72-hour fecal fat collection results demonstrate fat malabsorption, the D-xylose test is used to document the integrity of the intestinal mucosa.
    • Facilitated diffusion in the proximal intestine primarily absorbs D-xylose.
    • Approximately half of the absorbed D-xylose is excreted in urine, unmetabolized. If the absorption of D-xylose is impaired due to either a luminal factor (eg, bacterial overgrowth) or a reduced or damaged mucosal surface area (eg, surgical resection, celiac disease), urinary excretion is lower than normal.
    • Cases of pancreatic insufficiency usually result in normal urinary excretion because the absorption of D-xylose is still intact.
  • Tests of carbohydrate absorption
    • A simple sensitive test for carbohydrate malabsorption is the hydrogen breath test, in which patients are given an oral solution of lactose.
    • In cases of lactase deficiency, colonic flora digest the unabsorbed lactose, resulting in an elevated hydrogen content in the expired air.
    • Bacterial overgrowth or rapid transit also can cause an early rise in breath hydrogen, necessitating the use of glucose instead of lactose to make a diagnosis. However, 18% of patients are hydrogen nonexcretors, causing a false-negative test result.
  • Test of bile salt absorption
    • The bile salt breath test can determine the integrity of bile salt metabolism.
    • The patient is given oral conjugated bile salt, such as glycine cholic acid with the glycine radiolabeled in the carbon position.
    • The bile salt is deconjugated and subsequently metabolized by bacteria, leading to a radioactively labeled elevated breath carbon dioxide level if interrupted enterohepatic circulation, such as bacterial overgrowth, ileal resection, or disease, is present.
  • Schilling test
    • Malabsorption of vitamin B-12 may occur as a consequence of deficiency of intrinsic factor (eg, pernicious anemia, gastric resection), pancreatic insufficiency, bacterial overgrowth, ileal resection, or disease.
    • The 3-stage Schilling test results often can help differentiate these conditions.

Procedures

  • Upper endoscopy with small bowel mucosal biopsy
    • Establishing a definitive diagnosis of malabsorption of the mucosal phase often can be achieved by histological examination of biopsied mucosal specimens obtained during routine upper endoscopy.
    • Examples of conditions that can be diagnosed this way include celiac sprue, giardiasis, Crohn disease, Whipple disease, amyloidosis, abetalipoproteinemia, and lymphoma.

Histologic Findings

Depending on the cause, the histologic features of malabsorption vary. A frequently encountered histologic finding is villous atrophy, which is seen in celiac disease, tropical sprue, viral gastroenteritis, bacterial overgrowth, inflammatory bowel disease, immunodeficiency syndromes, lymphoma, and radiation enteritis.

More on Malabsorption

Overview: Malabsorption
Differential Diagnoses & Workup: Malabsorption
Treatment & Medication: Malabsorption
Follow-up: Malabsorption
References
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References

  1. Bai JC. Malabsorption syndromes. Digestion. Aug 1998;59(5):530-46. [Medline].

  2. Born P, Sekatcheva M, Rosch T, et al. Carbohydrate malabsorption in clinical routine: a prospective observational study. Hepatogastroenterology. Sep-Oct 2006;53(71):673-7.

  3. Camilleri M. Gastrointestinal problems in diabetes. Endocrinol Metab Clin North Am. Jun 1996;25(2):361-78. [Medline].

  4. Ciclitira PJ. AGA technical review on Celiac Sprue. American Gastroenterological Association. Gastroenterology. May 2001;120(6):1526-40. [Medline].

  5. Donner CS. Pathophysiology and therapy of chronic radiation-induced injury to the colon. Dig Dis. Jul-Aug 1998;16(4):253-61. [Medline].

  6. Doty JE, Fink AS, Meyer JH. Alterations in digestive function caused by pancreatic disease. Surg Clin North Am. Jun 1989;69(3):447-65. [Medline].

  7. Farthing MJ. Giardiasis. Gastroenterol Clin North Am. Sep 1996;25(3):493-515. [Medline].

  8. Fasano A, Catassi C. Current approaches to diagnosis and treatment of celiac disease: an evolving spectrum. Gastroenterology. Feb 2001;120(3):636-51. [Medline].

  9. Gudmand-Hoyer E, Skovbjerg H. Disaccharide digestion and maldigestion. Scand J Gastroenterol Suppl. 1996;216:111-21. [Medline].

  10. Hansson GC. Cystic fibrosis and chloride-secreting diarrhoea. Nature. Jun 23 1988;333(6175):711. [Medline].

  11. Hirschowitz BI. Zollinger-Ellison syndrome: pathogenesis, diagnosis, and management. Am J Gastroenterol. Apr 1997;92(4 Suppl):44S-48S; discussion 49S-50S. [Medline].

  12. Holt PR. Diarrhea and malabsorption in the elderly. Gastroenterol Clin North Am. Jun 2001;30(2):427-44. [Medline].

  13. Husebye E. Gastrointestinal motility disorders and bacterial overgrowth. J Intern Med. Apr 1995;237(4):419-27. [Medline].

  14. Janecki AJ. Why should a clinician care about the molecular biology of transport?. Curr Gastroenterol Rep. 2000;2(5):378-86. [Medline].

  15. Karras PJ, Pfeifer MA. Diabetic gastrointestinal autonomic neuropathy. Curr Ther Endocrinol Metab. 1997;6:462-5. [Medline].

  16. Kastin DA, Buchman AL. Malnutrition and gastrointestinal disease. Curr Opin Gastroenterol. Mar 2002;18(2):221-8. [Medline].

  17. Kelly KJ. Eosinophilic gastroenteritis. J Pediatr Gastroenterol Nutr. 2000;30 Suppl:S28-35. [Medline].

  18. Lai Ping So A, Mayer L. Gastrointestinal manifestations of primary immunodeficiency disorders. Semin Gastrointest Dis. Jan 1997;8(1):22-32. [Medline].

  19. Leffler D, Saha S, Farrell RJ. Celiac disease. Am J Manag Care. Dec 2003;9(12):825-31; quiz 832-3. [Medline].

  20. Levy E. The genetic basis of primary disorders of intestinal fat transport. Clin Invest Med. Oct 1996;19(5):317-24. [Medline].

  21. Lindley KJ, Macdonald S. Malabsorption in children. Practitioner. Mar 2001;245(1620):162-4, 166, 169-70 passim. [Medline].

  22. Lock G, Holstege A, Lang B, et al. Gastrointestinal manifestations of progressive systemic sclerosis. Am J Gastroenterol. May 1997;92(5):763-71. [Medline].

  23. Lovat LB, Pepys MB, Hawkins PN. Amyloid and the gut. Dig Dis. May-Jun 1997;15(3):155-71. [Medline].

  24. Meysman M, Debeuckelaer S, Reynaert H, et al. Systemic amyloidosis-induced diarrhea in sex-linked agammaglobulinemia. Am J Gastroenterol. Aug 1993;88(8):1275-7. [Medline].

  25. Owens SR, Greenson JK. The pathology of malabsorption: current concepts. Histopathology. Jan 2007;50(1):64-82. [Medline].

  26. Parnell ND, Ciclitira PJ. Review article: coeliac disease and its management. Aliment Pharmacol Ther. Jan 1999;13(1):1-13. [Medline].

  27. Pelletier VA, Galeano N, Brochu P, et al. Secretory diarrhea with protein-losing enteropathy, enterocolitis cystica superficialis, intestinal lymphangiectasia, and congenital hepatic fibrosis: a new syndrome. J Pediatr. Jan 1986;108(1):61-5. [Medline].

  28. Perri F, Clemente R, Festa V, et al. Pancreatic exocrine function tests. Scand J Gastroenterol. Oct 1998;33(10):1118-20. [Medline].

  29. Potter GD. Bile acid diarrhea. Dig Dis. Mar-Apr 1998;16(2):118-24. [Medline].

  30. Ramaiah C, Boynton RF. Whipple's disease. Gastroenterol Clin North Am. Sep 1998;27(3):683-95, vii. [Medline].

  31. Rose S, Young MA, Reynolds JC. Gastrointestinal manifestations of scleroderma. Gastroenterol Clin North Am. Sep 1998;27(3):563-94. [Medline].

  32. Saltzman JR, Russell RM. Nutritional consequences of intestinal bacterial overgrowth. Compr Ther. 1994;20(9):523-30. [Medline].

  33. Slater GH, Ren CJ, Siegel N, et al. Serum fat-soluble vitamin deficiency and abnormal calcium metabolism after malabsorptive bariatric surgery. J Gastrointest Surg. Jan 2004;8(1):48-55; discussion 54-5. [Medline].

  34. Vardy PA, Lebenthal E, Shwachman H. Intestinal lymphagiectasia: a reappraisal. Pediatrics. Jun 1975;55(6):842-51. [Medline].

  35. Vesy CJ, Peterson WL. Review article: the management of Giardiasis. Aliment Pharmacol Ther. Jul 1999;13(7):843-50. [Medline].

  36. Virally-Monod M, Tielmans D, Kevorkian JP, et al. Chronic diarrhoea and diabetes mellitus: prevalence of small intestinal bacterial overgrowth. Diabetes Metab. Dec 1998;24(6):530-6. [Medline].

  37. Washington K, Stenzel TT, Buckley RH, et al. Gastrointestinal pathology in patients with common variable immunodeficiency and X-linked agammaglobulinemia. Am J Surg Pathol. Oct 1996;20(10):1240-52. [Medline].

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Further Reading

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Keywords

malabsorption, malabsorption syndrome, defective digestion, defective absorption, digestion abnormality, maldigestion, lactase deficiency, lactose intolerance, celiac disease, celiac sprue, fat malabsorption, protein malabsorption, carbohydrate malabsorption, Zollinger-Ellison syndrome, ZES, ZE syndrome, ZE, Crohn disease, Crohn’s disease, Whipple disease, Whipple’s disease

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Contributor Information and Disclosures

Author

Jan-Michael A Klapproth, MD, Assistant Professor, Department of Medicine, Division of Digestive Diseases, Emory University School of Medicine
Jan-Michael A Klapproth, MD is a member of the following medical societies: American College of Gastroenterology, American Federation for Medical Research, American Gastroenterological Association, and Crohns and Colitis Foundation of America
Disclosure: Nothing to disclose.

Coauthor(s)

Vincent W Yang, MD, PhD, R Bruce Logue Professor, Director, Division of Digestive Diseases, Department of Medicine, Professor of Hematology and Oncology, Winship Cancer Institute, Emory University School of Medicine
Vincent W Yang, MD, PhD is a member of the following medical societies: Alpha Omega Alpha, American Gastroenterological Association, American Society for Clinical Investigation, and Association of American Physicians
Disclosure: Nothing to disclose.

Medical Editor

Tushar Patel, MB, ChB, Professor of Medicine, Director of Hepatology, Ohio State University Medical Center
Tushar Patel, MB, ChB is a member of the following medical societies: American Association for the Study of Liver Diseases and American Gastroenterological Association
Disclosure: Nothing to disclose.

Pharmacy Editor

Francisco Talavera, PharmD, PhD, Senior Pharmacy Editor, eMedicine
Disclosure: Nothing to disclose.

Managing Editor

Douglas M Heuman, MD, FACP, Director of Hepatology, McGuire Veterans Affairs Medical Center, Professor, Department of Internal Medicine, Division of Gastroenterology, Virginia Commonwealth University School of Medicine
Douglas M Heuman, MD, FACP is a member of the following medical societies: American Association for the Study of Liver Diseases, American College of Physicians, and American Gastroenterological Association
Disclosure: Nothing to disclose.

CME Editor

Alex J Mechaber, MD, FACP, Assistant Dean for Medical Curriculum, Associate Professor of Medicine, Division of General Internal Medicine, University of Miami Miller School of Medicine
Alex J Mechaber, MD, FACP is a member of the following medical societies: Alpha Omega Alpha, American College of Physicians-American Society of Internal Medicine, and Society of General Internal Medicine
Disclosure: Nothing to disclose.

Chief Editor

Julian Katz, MD, Clinical Professor of Medicine, Drexel University College of Medicine; Consulting Staff, Department of Medicine, Section of Gastroenterology and Hepatology, Hospital of the Medical College of Pennsylvania
Julian Katz, MD is a member of the following medical societies: American College of Gastroenterology, American College of Physicians, American Gastroenterological Association, American Geriatrics Society, American Medical Association, American Society for Gastrointestinal Endoscopy, American Society of Law Medicine and Ethics, American Trauma Society, Association of American Medical Colleges, and Physicians for Social Responsibility
Disclosure: Nothing to disclose.

 
 
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