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Malabsorption
Classification and external resources

Whipple's disease: Alcian blue with apparently eosin counterstain enlarged villus with many macrophages
ICD-10 (K90.)
ICD-9 579
DiseasesDB 7698
MedlinePlus 000299
eMedicine med/1384
MeSH D008286

Malabsorption is a state arising from abnormality in absorption of food nutrients across the gastrointestinal(GI) tract.

Impairment can be of single or multiple nutrients depending on the abnormality. This may lead to malnutrition and variety of anaemias[1].

Contents

Classification

Some prefer to classify malabsorption clinically into three basic categories[2]:

(1) selective, as seen in lactose malabsorption;
(2) partial, as observed in a-Beta-lipoproteinemia, and
(3) total as in coeliac disease.

Pathophysiology

The main purpose of the gastrointestinal tract is to digest and absorb nutrients (fat, carbohydrate, and protein), micronutrients (vitamins and trace minerals), water, and electrolytes. Digestion involves both mechanical and enzymatic breakdown of food. Mechanical processes include chewing, gastric churning, and the to-and-fro mixing in the small intestine. Enzymatic hydrolysis is initiated by intraluminal processes requiring gastric, pancreatic, and biliary secretions. The final products of digestion are absorbed through the intestinal epithelial cells.

Malabsorption constitutes the pathological interference with the normal physiological sequence of digestion (intraluminal process), absorption (mucosal process) and transport (postmucosal events) of nutrients[3].

Intestinal malabsorption can be due to:[4]

Causes

Due to infective agents Due to structural defects[5]
Due to mucosal abnormality Due to enzyme deficiencies
  • Lactase deficiency inducing lactose intolerance (constitutional, secondary or rarely congenital)
  • Sucrose intolerance
  • Intestinal disaccharidase deficiency
  • Intestinal enteropeptidase deficiency
Due to digestive failure Due to other systemic diseases affecting GI tract

Clinical features

Small intestine : major site of absorption

It can present in variety of ways and features might give clue to underlying condition. Symptoms can be intestinal or extra-intestinal - the former predominates in severe malabsorption.

Diagnosis

There is no specific test for Malabsorption. As for most medical conditions, investigation is guided by symptoms and signs. Moreover, tests for pancreatic function are complex and varies widely between centres.

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Blood Tests

Specific tests are carried out to determine underlying cause.
IgA tissue trans glutamate or IgA antiendomysium assay for gluten sensitive enteropathy.

Stool studies

  • Microscopy is particularly useful in diarrhoea, may show protozoa like giardia, ova, cyst and other infective agents.
  • Fecal fat study to diagnose steatorrhoea is less frequently performed nowadays.
  • Low elastase is indicative of pancreatic insufficiency. Chymotrypsin and pancreolauryl can be assessed as well[9]

Radiological studies

Interventional studies

Biopsy of small bowel showing coeliac disease manifested by blunting of villi, crypt hyperplasia, and lymphocyte infiltration of crypts.
  • Endoscopy is frequently undertaken, but to visualise small intestine, which can be up to 7m long, is indeed a daunting task.
OGD to reveal duodenal lesion also for D2 biopsy (for celiac disease, tropical sprue, Whipple's disease, A-b-lipoproteinemia etc.)
Enteroscopy for enteropathy and jejunal aspirate and culture for bacterial overgrowth
Colonoscopy is helpful in colonic or ileal lesion.

Other investigations

Management

Treatment is directed largely towards management of underlying cause.

  • Replacement of nutrients, electrolytes and fluid may be necessary. In severe deficiency, hospital admission may be required for parenteral administration, often advice from dietitian is sought. People whose absorptive surface are severely limited from disease or surgery may need long term total parenteral nutrition. Pancreatic enzymes are supplemented orally in insufficiencies.
  • Dietary modification is important in some conditions. Life-long avoidance of particular food or food constituent may be needed in Celiac disease or lactose intolerance.
  • Bacterial overgrowth usually respond well to course of antibiotic. Use of cholestyramine to bind bile acid will help reducing diarrhea in bile acid malabsorption.

See also

External links

  • Practice guideline from World Gastroenterology Organisation [2]
  • Tests for malabsorption; from British Society for Gastroenterology (2003)[3]

References

  1. ^ Jensen, Jonathan E. "Malabsorption Syndromes - Page 1". Colorado center for digestive disorders. http://www.gastromd.com/education/malabsorptionsyndromes.html. Retrieved 2007-05-10.  
  2. ^ Gasbarrini G, Frisono M: Critical evaluation of malabsorption tests; in G. Dobrilla, G. Bertaccini, G. Langman (Editor) (1986). Problems and Controversies in Gastroenterology. New York: Raven Pr. pp. 123–130. ISBN 88-85037-75-5.  
  3. ^ a b c Bai J (1998). "Malabsorption syndromes". Digestion 59 (5): 530–46. doi:10.1159/000007529. PMID 9705537.  
  4. ^ Walker-Smith J, Barnard J, Bhutta Z, Heubi J, Reeves Z, Schmitz J (2002). "Chronic diarrhea and malabsorption (including short gut syndrome): Working Group Report of the First World Congress of Pediatric Gastroenterology, Hepatology, and Nutrition". J. Pediatr. Gastroenterol. Nutr. 35 Suppl 2: S98–105. doi:10.1097/00005176-200208002-00006. PMID 12192177.  
  5. ^ M. S Losowsky, (1974). Malabsorption in clinical practice. Edinburgh: Churchill Livingstone. ISBN 0-443-01007-2.  
  6. ^ health a to z"Malabsorption syndrome". http://www.healthatoz.com/healthatoz/Atoz/common/standard/transform.jsp?requestURI=/healthatoz/Atoz/ency/malabsorption_syndrome.jsp. Retrieved 2007-05-10.  
  7. ^ Bertomeu A, Ros E, Barragán V, Sachje L, Navarro S (1991). "Chronic diarrhea with normal stool and colonic examinations: organic or functional?". J. Clin. Gastroenterol. 13 (5): 531–6. doi:10.1097/00004836-199110000-00011. PMID 1744388.  
  8. ^ Read N, Krejs G, Read M, Santa Ana C, Morawski S, Fordtran J (1980). "Chronic diarrhea of unknown origin". Gastroenterology 78 (2): 264–71. PMID 7350049.  
  9. ^ Thomas P, Forbes A, Green J, Howdle P, Long R, Playford R, Sheridan M, Stevens R, Valori R, Walters J, Addison G, Hill P, Brydon G (2003). "Guidelines for the investigation of chronic diarrhoea, 2nd edition". Gut 52 Suppl 5: v1–15. doi:10.1136/gut.52.suppl_5.v1. PMID 12801941.  [1].

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