Malabsorption

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Malabsorption syndrome:

Malabsorption syndrome Presented by : Mustafa Mohd Ahmed IBN SINA HOSPITAL

Malabsorption:

Malabsorption The Malabsorption is the failure to absorb or digest normally one or more dietary constituents. patients with Malabsorption often complaint of diarrhea ,some times the distinction between Malabsorption and diarrhea of other causes is difficult

Malabsorption:

Malabsorption Dietary nutrient absorption –in small b. Ca., iron, folic acid – absorbed in proximal SB Cobalamine , bile acid – in the ileum Glucose, a.a ., lipids – throughout the SB Malabsorption could be: Primary (congenital defects) Secondary (acquired defects) Clinical Sx usually due to: Malabsorption of fat &/or carbohydrate Steatorrhea  main feature in most cases

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Diarrhea Steatorrhea Watery D. Inflammatory D. Inflammation Nutrient malabsorption Intestinal secretion

mechanisms:

mechanisms Luminal phase (processing defect) Digestive enzyme deficiency / inactivation bile salt synthesis; Excretion; loss; bile salt de-conjugation gastric acid; intrinsic factor (p. anemia) Bacterial over growth Mucosal phase Epithelial transport defect – inflammations infections /decrease in surface area Brush border hydrolysis defect congenital/acquired disacharidase deficiency Post-absorptive phase Enterocyte processing – Abetalipoproteinemia Lymphocytic obstruction – intestinal lymphangectasia

Signs & symptoms:

Signs & symptoms Calori Weight loss with normal appetite Fat Pale,voluminous,greasy offensive diarrhea Protein Edema, muscle atrophy, amenorrhea carbohydrate Abdominal bloating, flatus, w. diarrhea B12 Macrocytic anemia Subacut combined degeneration of sp.cord Folic acid Macrocytic anemia Vit B (general) Cheliosis, glossitis,A.stomatitis, Acrodermatitis Iron Microcytic anemia Ca & Vit D Osteomalacea (bone pain,pathologic #), Tetany Vit A Follicular hyperkeratosis, Night blindness VIt K Bleeding diathesis, Hematoma

Diagnostic studies:

Diagnostic studies A. Blood test : Hemoglobin and hematocrit may identify anemia .Alow mean cell volume may be found in iron deficiency ,where as a high MCV may result from folate or vitaminB12 deficiency. protein ,amylase , calcium,folate,liver enzymes ,vitaminB12 may be abnormal

B. Radiographic studies:

B. Radiographic studies 1. plain x ray or computed tomography scan of the abdomen may show calcification within the pancreas, which indicates chronic pancreatic insufficiency 2. A barium examination often the finding is not specific. The bowl may be dilated and the barium is diluted because of the increased intraluminal fluid

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The more specific finding is thickening of the intestinal folds caused by an infiltrative process, such as lymphoma, whipple’s disease, or amyloidosis .The narrowed , irregular terminal ileum in chron’s disease is virtually diagnostic ,although lymphoma and other infiltrative disorders also must be considered . Diverticular ,fistula ,and surgical alteration in bowl anatomy also may be evident .

others:

others ERCP Detect ductal abnormalities Other diagnostic/therapeutic applications MRCP Detect ductal and parenchymal abnormalities EUS Detect ductal and parenchymal abnormalities Allows tissue sampling

Fecal fat test:

Fecal fat test patient should ingest 80 to 100 g of fat per day 1. Qualitative screening test : The Sudan stain for fecal fat . Stool sample is smeared on microscopic slide and mixed with ethanolic Sudan III and glacial acetic acid

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The slide is covered, heated just until boiling, and then examined for fatty acid globules.100 globules greater than 6micro meter in diameter per high –power field(*430) indicates a definite increase in fecal fat excretion. GI/Liver secrets plus 4 th edition2010

Sudan black stain :

Sudan black stain

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The quantitative fecal fat : more accurate than qualitative ,but the collection of the stool is not comfortable to the patients ,family ,and nurses . the stool is collected for 72 hours in large container , which can be enclosed in plastic bag and refrigerated to contain unpleasant odors . Normally is 6grams/24hours manual of gastroenterology diagnosis and therapies 4 th edn 2009

Other Tests of Fat Malabsorption:

O ther Tests of Fat Malabsorption Acid steatocrit is gramovetric assay performed on spot stool sample its simple and accurate . 14C-triolein, 13C-triglyceride breath tests Near infrared reflectance analysis (NIRA) Can measure fecal fat, nitrogen and CHO As accurate and less time consuming than 72 hr fecal fat collection Performed in less than one minute

Pancreatic test:

Pancreatic test 1. Collection of pancreatic secretion from the duodenum: After stimulation of the pancreas with secretin or with meals. The volume of pancreatic secretions( bicarbonate and enzymes)can be measured , e.g bicarbonate less than 90mmol/L suggest pancreatic insufficiency. But the result may be unreliable in many G.I labs manual of gastroenterology diagnosis and therapies 4 th edn

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2 . The bentiromide test: Its a pancreatic secretion test not require duodenum intubation. Its chemical name is N- benzoyal -L- tyrosyl -P- aminobenzoic acid. the test is by taking a single dose of500 mg of bentiromide after an over night fast ,then urine is collected for 6 hours . The pancreatic enzyme chymotrypsin cleaves the molecule within the lumen of the small intestine , releasing

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paraamino benzoic acid (PABA) . The PABA is absorbed and excreted in the urine .less than 60% excretion of PABA suggest pancreatic insufficiency ,although mucosal disorders ,renal disease ,severe liver ,and diabetes also can cause low PABA excretion. manual of gastroenterology diagnosis and therapy

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3. Radiographic studies : Although computed tomography of the abdomen and endoscopic retrograde cholangiopancreatography do not measure pancreatic function directly ,abnormalities such as dilated or stricture ,calcification ,and pancreatic masses can imply pancreatic disease

Bile acid breath test:

Bile acid breath test Conjugated bile acid that are secreted into the duodenum are reabsorbed (95%) in terminal ileum .If radio labeled (14c)-glycocholate is given orally ,in normal ones 5% enter the colon and deconjegated by bacteria ,then the CO2 is measured in expired air. Bacterial over growth, disease or resection of terminal ileum gives larger amount of CO2 in the lungs

Small Bowel Culture:

Small Bowel Culture Aspirate is the “Gold Standard” test for small intestine bacterial overgrowth Abnormal > 10 5 Many limitations Invasive Expensive Contamination Many bacterial uncultivatable Difficulty culturing anaerobes

Breath test :

Breath test Specific carbohydrate malabsorption Lactose, fructose, sucrose Hydrogen Small intestinal bacterial overgrowth Glucose, lactulose Hydrogen Xylose, glycocholate 14 CO2 Fat malabsorption 14 C-triolein Historical interest mainly

Urinary D-Xylose Test :

Urinary D- Xylose Test D- Xylose , is a pentose, absorbed almost exclusively in the small intestine . 25 g D- xylose dissolved in 500 ml of water is given orally and collecting urine for 5 h with additional 1L of water. An abnormal test (<4.5 g excretion) reflects the presence of duodenal/ jejunal mucosal disease. The D-xylose test can also be low in bacterial overgrowth, dehydration , ascietes, and renal disease .To avoid this a blood test xylose level at 2 h might be done .The normal is above 40 mg/dl manual of gastroenterology diagnosis and therapy

Lactose absorption test:

Lactose absorption test Lactase is hydrolyze lactose to glucose and galactose .The test : a fasting blood glucose level is drawn , and the patient swallow 50% of lactose mixed in 500 mL of water .the blood glucose level 15,30,60,and 90 minutes. If he is lactase deficient ,the blood glucose fail to rise more than 20mg/ dL above the fasting level

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Lactose absorption also can be done by measuring breath hydrogen test after oral 25mg lactose .If lactose absorption in small intestine impaired large amount of it reach the colon where bacterial ferment it , forming excessive amount of hydrogen which is absorbed and expired in lungs.

Tests of Protein Malabsorption:

Tests of Protein Malabsorption Nutrient balance studies with fecal nitrogen measurement Radioisotopic methods 51 Cr-labeled albumin 99 mTc-labeled transferrin 125 I-labeled albumin Indirect methods Fecal - 1 antitrypsin clearance (> 25 mg/d)

The Schilling test:

The Schilling test administering 58Co-labeled cobalamin orally and 1 mg cobalamin is administered intramuscularly 1 h later and collecting urine for 24 h, all absorbed radiolabeled cobalamin will be excreted in urine, following ingestion of the radiolabeled cobalamin . abnormal (usually defined as <10% excretion in24 hours).

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1.then add intrinsic factor if it is corrected that mean IF deficiency (gastric atrophy or pernicious anemia) 2.if still low then either pancreatic, terminal ileum disease, or bacterial over growth 3.pancreatic enzymes degrade R protein in proximal small intestine 4.other conditions lead to low urinary excretion are poor hydration, decreased circulatory volume ,renal disease and infestation with fish warm.

Schilling test cont….:

Schilling test cont…. 58Co-Cbl With Intrinsic factor With pancreatic enzyme 5 Days Of Ab Pernicious Anemia  N   Chronic Pancreatitis   N  Bacterial overgrowth    N Ileal disease    

Small bowl biopsy modified from Trier:

Small bowl biopsy modified from Trier a. Disorders in which the biopsy is invariably diagnostic: 1. celiac sprue (the biopsy is non specific , but coupled with a clinical response to the elimination of dietary gluten and + ve Ab , it is diagnostic) 2.Whipple’s disease 3. Abetalipoproteinmia 4.Agammaglobulinemia 5. mycobacterium avium-intracellulare

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b. Disorders biopsy may or may not be specific 1. intestinal lymphoma 2. intestinal lymphangiectasia 3. esinophilic enteritis 4. systemic mastocytosis 5. parasitic infection 6. amyloidosis 7.hypogammaglobulinemia 8.dysgammaglobulinemia

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c.Biopsy may abnormal but not diagnostic 1. tropical sprue 2. folate deficiency 3.vitamin B12 deficiency 4. irradiation enteritis 5. Zollinger -Ellison syndrome 6. small bowl bacterial over growth 7. drug- induced lesion 8.malnutrition 9.Graft –versus- host reaction 10.viral enteritis

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d. disorders in which biopsy is normal 1. pancreatic exocrine insufficiency 2.cirrhosis 3. post gastrectomy malabsorption 4. primary lactase deficiency 5. irritable bowl syndrome

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Disorder Small bowl x-ray Fecal fat Xylose tolerance test Shilling test Small bowl biopsy Pancreatic exocrine insufficiency abnormal Severe steatorrhea normal May be abnormal normal Bile acid insufficiency normal Mild to moderate steatorrhea normal normal normal Small bowl mucosal disease abnormal Mid to severe steatorrhea abnormal Usually normal abnormal Lymphatic disease May be normal Mild steatorrhea normal normal abnormal

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Selection of tests in evaluating malabsorption Quantitaive fecal fat Normal Abnormal D- xylose test Normal Abnormal Abd. Radiograph 14 C-D- xylose test Bentiromide test CT- abd . Normal Small intestinal Bx Abnormal Jej culture Tetracyclin Then repeat breath test

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