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| {{SK}} Malabsorption syndrome | | {{SK}} Malabsorption syndrome |
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| ==Overview== | | ==[[Malabsorption overview|Overview]]== |
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| '''Malabsorption''' is a state arising from abnormality in [[digestion]] or [[absorption]] of [[Nutrient|food nutrients]] across the [[gastrointestinal tract|gastrointestinal(GI) tract]].
| | ==[[Malabsorption historical perspective|Historical Perspective]]== |
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| Impairment can be of single or multiple nutrients depending on the abnormality. This may lead to [[malnutrition]] and variety of [[anemia|anaemias]]<ref>{{cite web | last = Jensen | first = Jonathan E |title=Malabsorption Syndromes - Page 1| publisher =Colorado center for digestive disorders|url=http://www.gastromd.com/education/malabsorptionsyndromes.html |accessdate=2007-05-10 |format= |work=}}</ref>.
| | ==[[Malabsorption classification|Classification]]== |
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| Some prefer to classify malabsorption clinically into three basic categories<ref>Gasbarrini G, Frisono M: Critical evaluation of malabsorption tests; in {{cite book |author=G. Dobrilla, G. Bertaccini, G. Langman (Editor) |title=Problems and Controversies in Gastroenterology |publisher=Raven Pr |location= New York |year= 1986 |pages= 123-130|isbn=88-85037-75-5 |oclc= |doi=}}</ref>:
| | ==[[Malabsorption pathophysiology|Pathophysiology]]== |
| :(1) '''selective''', as seen in lactose malabsorption;
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| :(2) '''partial''', as observed in a-Beta-lipoproteinemia, and
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| :(3) '''total''' as in celiac disease.
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| == Pathophysiology== | | ==[[Malabsorption causes|Causes]]== |
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| The main purpose of the GI tract is to [[digestion|digest]] and [[absorption|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 differential diagnosis|Differentiating Malabsorption from other Diseases]]== |
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| Malabsorption constitutes the pathological interference with the normal physiological sequence of digestion (intraluminal process), absorption (mucosal process) and transport (postmucosal events) of nutrients<ref name="julio">{{cite journal |author=Bai J |title=Malabsorption syndromes |journal=Digestion |volume=59 |issue=5 |pages=530-46 |year=1998 |pmid=9705537}}</ref>.
| | ==[[Malabsorption epidemiology and demographics|Epidemiology and Demographics]]== |
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| Intestinal malabsorption can be due to<ref>{{cite journal |author=Walker-Smith J, Barnard J, Bhutta Z, Heubi J, Reeves Z, Schmitz J |title=Chronic diarrhea and malabsorption (including short gut syndrome): Working Group Report of the First World Congress of Pediatric Gastroenterology, Hepatology, and Nutrition |journal=J. Pediatr. Gastroenterol. Nutr. |volume=35 Suppl 2 |issue= |pages=S98-105 |year=2002 |pmid=12192177}}</ref>
| | ==[[Malabsorption risk factors|Risk Factors]]== |
| * mucosal damage ([[enteropathy]])
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| * congenital or acquired reduction in absorptive surface
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| * Defects of specific hydrolysis
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| * Defects of ion transport
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| * pancreatic insuffeciency
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| * impaired [[enterohepatic circulation]]
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| ==Causes== | | ==[[Malabsorption screening|Screening]]== |
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| '''Due to infective agents'''
| | ==[[Malabsorption natural history, complications and prognosis|Natural History, Complications and Prognosis]]== |
| *[[Whipple's disease]]
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| *Intestinal [[tuberculosis]]
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| *[[HIV]] related malabsorption
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| *[[Tropical sprue]]
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| *[[traveller's diarrhoea]]
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| *[[Parasites]] .e. g. [[giardiasis|''Giardia lamblia'']], [[Diphyllobothrium|fish tape worm]] (B12 malabsorption); [[Strongyloides stercoralis|round warm]] , [[hookworm]] (''Ancylostoma duodenale'' and ''Necator americanus'')
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| '''Due to structural defects'''<ref>{{cite book |author=M. S Losowsky, |title=Malabsorption in clinical practice |publisher=Churchill Livingstone |location=Edinburgh |year= |pages= |isbn=0-443-01007-2 |oclc= |doi=}}</ref>
| | ==Diagnosis== |
| *[[blind loop syndrome|Blind loops]]
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| *Inflammatory bowel diseases commonly in [[Crohn's Disease]]
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| *Intestinal hurry from Post-[[gastrectomy]]; post-[[vagotomy]], gastro-jejunostomy
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| *[[Fistulae]], [[Diverticulum|diverticulae]] and [[strictures]],
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| *Infiltrative conditions such as [[amyloidosis]], [[lymphoma]], Eosinophilic gastroenteropathy
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| *[[Radiation enteritis]]
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| *[[Systemic sclerosis]] and collagen vascular diseases
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| '''Due to mucosal abnormality'''
| | [[Malabsorption diagnostic criteria|Diagnostic Criteria]] | [[Malabsorption history and symptoms|History and Symptoms]] | [[Malabsorption physical examination|Physical Examination]] | [[Malabsorption laboratory findings|Laboratory Findings]] | [[Malabsorption electrocardiogram|EKG]] | [[Malabsorption CT|CT]] | [[Malabsorption MRI|MRI]] | [[Malabsorption echocardiography or ultrasound|Echocardiography or Ultrasound]] | [[Malabsorption other imaging findings|Other Imaging Findings]] | [[Malabsorption other diagnostic studies|Other Diagnostic Studies]] |
| *[[Coeliac disease]]
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| *Cows' milk intolerance
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| *Soya milk intolerance
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| '''Due to enzyme defeciencies'''
| | ==Treatment== |
| *Lactase deficiency inducing [[lactose intolerance]] (constitutional, secondary or rarely congenital)
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| *[[Sucrose intolerance]]
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| *Intestinal disaccharidase defeciency
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| *Intestinal enteropeptidase defeciency
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| '''Due to digestive failure'''
| | [[Malabsorption medical therapy|Medical Therapy]] | [[Malabsorption surgery|Surgery]] | [[Malabsorption primary prevention|Primary Prevention]] | [[Malabsorption secondary prevention|Secondary Prevention]] | [[Malabsorption cost-effectiveness of therapy|Cost-Effectiveness of Therapy]] | [[Malabsorption future or investigational therapies|Future or Investigational Therapies]] |
| *Pancreatic insuffeciencies:
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| **[[cystic fibrosis]]
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| **[[chronic pancreatitis]]
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| **[[carcinoma of pancreas]]
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| **[[Zollinger-Ellison syndrome]]
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| *[[Bile salt]] malabsorption
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| **terminal ileal disease
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| **[[obstructive jaundice]]
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| **[[bacterial overgrowth]]
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| '''Due to other [[systemic disease]]s affecting GI tract'''
| | ==Case Studies== |
| *[[Hypothyroidism]] and [[hyperthyroidism]]
| | [[Malabsorption case study one|Case #1]] |
| *[[Addison's disease]]
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| *[[Diabetes mellitus]]
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| *[[Hyperparathyroidism]] and [[Hypoparathyroidism]]
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| *[[Carcinoid syndrome]]
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| *Malnutrition
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| *[[Abetalipoproteinemia|Abeta-lipoproteinemia]]
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| == Clinical features== | |
| [[Image:Small-Intestine-highlighted.gif|thumb|left|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, former predominates in severe malabsorption.
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| * [[Diarrhoea]],often [[steatorrhoea]] is the most common feature. Watery, diurnal and nocturnal, bulky, frequent stools are the clinical hallmark of overt malabsorption. It is due to impaired water, carbohydrate and electrolyte absorption or irritation from unabsorbed fatty acid. Latter also result in [[bloating]], [[flatulence]] and abdominal discomfort. Cramping pain usually suggest obstructive intestinal segment e.g. in crohn's disease especially if persists after defecation. <ref name="julio"/>
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| * Weight loss can be significant despite increased oral intake of nutrients<ref>health ato z {{cite web |url=http://www.healthatoz.com/healthatoz/Atoz/common/standard/transform.jsp?requestURI=/healthatoz/Atoz/ency/malabsorption_syndrome.jsp |title=Malabsorption syndrome |accessdate=2007-05-10 |format= |work=}}</ref>.
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| * Growth retardation, failure to thrive, delayed puberty in children
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| * Swelling or [[oedema]] from loss of protein
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| * Anaemias, commonly from vitamin [[B12]], [[folic acid]] and [[iron]] defeciency presenting as fatigue and weakness.
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| * Muscle cramp from decreased [[vitamin D]], calcium absorption. Also lead to [[osteomalacia]] and [[osteoporosis]]
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| * Bleeding tendencies from [[vitamin K]] and other [[coagulation factor]] defeciencies.
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| == Diagnosis==
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| 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'''
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| *Routine blood tests may reveal [[anaemia]], high [[ESR]] or low [[serum albumin|albumin]]; which has high sensitivity for presence of organic disease <ref>{{cite journal |author=Bertomeu A, Ros E, Barragán V, Sachje L, Navarro S |title=Chronic diarrhea with normal stool and colonic examinations: organic or functional? |journal=J. Clin. Gastroenterol. |volume=13 |issue=5 |pages=531-6 |year=1991 |pmid=1744388}}</ref><ref>{{cite journal |author=Read N, Krejs G, Read M, Santa Ana C, Morawski S, Fordtran J |title=Chronic diarrhea of unknown origin |journal=Gastroenterology |volume=78 |issue=2 |pages=264-71 |year=1980 |pmid=7350049}}</ref>. In this setting, [[Microcytic#Microcytic anaemia|microcytic anaemia]] usually implies iron deficiency and [[macrocytosis]] can be from impaired [[folic acid]] or [[B12]] absorption or both. Low cholesterol or triglyceride may give clue toward fat malabsorption as low calcium and phosphate toward [[osteomalacia]] from low vitamin D.
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| *Specific vitamins like [[vitamin D]] or [[micro nutrient]] like zinc levels can be checked. Fat soluble vitamins (A, D, E & K) are affected in fat malabsorption. Prolonged [[prothrombin time]] can be from [[vitamin K]] deficiency.
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| *Serological studies
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| :Specific tests are carried out to determine underlying cause.
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| :[[IgA]] tissue trans glutamate or IgA antiendomysium assay for [[Coeliac disease|gluten sensitive enteropathy]].
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| '''Stool studies'''
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| * Microscopy is particularly useful in diarrhoea, may show protozoa like giardia, ova, cyst and other infective agents.
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| *[[Fecal fat|Fecal fat study]] to diagnose [[steatorrhoea]] is less frequently performed nowadays.
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| *Low [[elastase]] is indicative of pancreatic insufficiency. [[Chymotrypsin]] and pancreolauryl can be assessed as well<ref>{{cite journal |author=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 |title=Guidelines for the investigation of chronic diarrhoea, 2nd edition |journal=Gut |volume=52 Suppl 5 |issue= |pages=v1-15 |year=2003 |pmid=12801941}}[http://www.bsg.org.uk/pdf_word_docs/cd_body.pdf].
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| </ref>
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| '''Radiological studies'''
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| *[[Barium follow through]] is useful in delineating [[small intestine|small intestinal]] [[anatomy]]. [[Barium enema]] may be undertaken to see colonic or ileal lesions.
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| *CT abdomen is useful in ruling out structural abnormality, done in pancreatic protocol when visualising pancreas.
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| *[[MRCP]] to complement or as an alternative to [[ERCP]]
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| '''Interventional studies'''
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| [[Image:Coeliac path.jpg|thumb|left|Biopsy of [[small bowel]] showing coeliac disease manifested by blunting of [[villi]], crypt hyperplasia, and [[lymphocyte]] infiltration of crypts.]]
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| *Endoscopy is frequently undertaken, but to visualise small intestine which can be up to 7m long is indeed a daunting task.
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| :[[OGD]] to reveal duodenal lesion also for D2 biopsy (for celiac disease, tropical sprue, Whipple disease, A-b-lipoproteinemia etc.)
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| :[[Enteroscopy]] for enteropathy and jejunal aspirate and culture for bacterial overgrowth
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| :[[Colonoscopy]] is helpful in colonic or ileal lesion.
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| *[[ERCP]]
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| '''Other investigations'''
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| *[[Radionuclide|Radio isotope]] tests e.g. 75SeHCAT, 95mTc to exclude terminal ileal disease.
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| *Sugar probes or sub 51Cr-EDTA to determine intestinal permeability<ref name="julio"/>.
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| *Glucose hydrogen breath test for [[bacterial overgrowth]]
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| *[[D-xylose]] absorption test. lower level in urine after ingestion indicates bacterial overgrowth or reduced absorptive surface. normal in pancreatic insufficiency.
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| *Bile salt breath test to determine [[bile salt]] malabsorption.
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| *[[Schilling test]] to establish cause of B12 deficiency.
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| *Lactose H2 breath test for [[lactose intolerance]]
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| == Management==
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| Treatment is directed largely towards management of underlying cause.
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| *Replacement of nutrients, electrolytes and fluid may be necessary. In severe defeciency hospital admission may be required for parentral administration, often advice from dietician is sought. People whose absortive surface are severely limited from disease or surgery may need long term [[total parenteral nutrition]]. Pancreatic [[enzymes]] are supplimented orally in insuffeciencies.
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| *Dietary modification is important in some conditions. Life long avoidance of particular food or food constituent may be needed in Celiac disease or lactose intolerence.
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| *Bacterial overgrowth usually respond well to course of antibiotic. Use of [[cholestyramine]] to bind bile acid will help reducing diarrhoea in bile acid malabsorption.
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| == Related Chapters == | | == Related Chapters == |
