Absorption disorders for gestroenterology .ppt

this presentation is good for anesthesia residents

1. Disorders of Absorption
(Malabsorption syndrome)
Rezene Berhe, MD
Consultant internist and
Gastroenterologist
03/12/25 1

2. Disorders of Absorption
Learning objective
•Describe the definition
•State the pathophysiology
•Identify the clinical features of global and
partial MAS
•Describe the diagnostics needed and
approach to diagnose MAS
•State the management principles
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3. Case
•A 35 year old male from presented with
history of watery frequent diarrhea and un-
quantified significant weight loss since one
year.
–Is he having MAS? What possible explanation
do we have?
–What additional information do you need?
–How would you investigate and treat?
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4. Definition and classification
Key words:
•MAS
•Tropical MAS
•Intestinal failure
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5. •Impaired absorption of one or more dietary
nutrients from SI
•Abnormality of the GIT affecting
–Digestion
–Absorption
–Transport of nutrients
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6. Defn. cont……..
•Tropical Malabsorption:
–chronic diarrhea, weight loss and multiple
nutritional deficiencies that affects indigenous
residents of tropical countries and also travelers
visiting or residing in the tropics.
(Tropical MAS: B S Ramakrishna: Postgrad med J
2006;82)
•Intestinal failure:
–Absorption capacity falling short of 85%.
–Reduction in functioning gut mass
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7. Classification
•Global (Diffuse) VS Focal (Isolated)
•Primary or Idiopathic VS secondary where
a definitive causative factor is identified.
•Enteral MAS VS Pancreatico- biliary MAS
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8. Pathophysiology
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9. Carbohydrate digestion and
absorption
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10. Digestion and absorption of
protein
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11. Fat digestion and absorption
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12. Water and electrolyte Absorption
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13. Water and chloride secretion
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14. Vit B12 absorption
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15. Pathophysiology
Duodenum: Calcium, Iron,
Glucose, Galactose, fructose
Jejunum: AA, peptides, FA,
monoglycerides, Vitamins
Ileum: Vit B12, bile
Colon: water,
Stomach: ETOH
Site of Absorption
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16. Causes of MAS
•Pre mucosal
•Mucosal
•Post mucosal
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17. Causes cont….
1. Luminal phase (Pre-mucosal):
–Impaired digestion
–Bile acid/Enzyme deficiency: luminal and brush
border processing:
•Substrate hydrolysis- Digestive enzymes
•Fat solubilization- Bile salts
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18. Examples of conditions causing Malabsorption
Nature of malabsorptive defect Example
A. Substrate hydrolysis
1. Digestive enzyme deficiency
2. Digestive enzyme inactivation
3. Dyssynchrony of enzyme release,
inadequate mix
Chronic pancreatitis
Zollinger-Ellison syndrome
Post Billroth II procedure
B. Fat solubilization
1. Diminished bile salt synthesis
2. Impaired bile secretion
3. Bile salt de-conjugation
4. Increased bile salt loss
Cirrhosis
Chronic cholestasis
Bacterial overgrowth
Ileal disease or resection
C. Luminal availability of specific nutrients
1. Diminished gastric acid
2. Diminished intrinsic factor
3. Bacterial consumption of nutrients
Atrophic gastritis - vitamin B12
Pernicious anemia - vitamin B12
Bacterial overgrowth - vitamin B12
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19. Cont…
2. Mucosal Phase: (mucosal absorption)
•-Brush border hydrolysis
•-Epithelial transport (Esterification, Chylomicron
• formation)
•-Structural: Reduced absorption (resection or disease)
3. Post mucosal phase:
–Enterocyte processing- beta-lipoprotein
–Lymphatic transport
•Defect in any of these three phases can cause
malabsorption03/12/25 19

20. Examples of conditions causing malabsorption
Nature of malabsorptive defect Example
Mucosal (absorptive) phase
A. Brush border hydrolysis
1.Congenital disaccharidase defect
2. Acquired disaccharidase defect
Sucrase-isomaltase
deficiency
Lactase deficiency
B. Epithelial transport
1.Nutrient-specific defects in transport
2. Global defects in transport
Hartnup's disease
Celiac sprue
Post mucosal/Postabsorptive, processing
phase
A.Enterocyte processing
B.Lymphatic
Abetalipoproteinemia
Intestinal
lymphangiectasia
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21. Clinical features
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22. CF
Determining factors of clinical presentations
Etiologies of MAS
Global vs partial cause
Geographic variation
Age
Severity of the underlying disease
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23. Diagnosis cont……
•High index of suspicion:
•Detailed history:
–Liver disease
–Chronic pancreatitis or pancreatic tumor
–Infectious etiologies- Giardia, Tb, HIV
–Systemic illness: DM, thyrotoxicosis
–Family history
–Drug history
–History of surgery

Diarrhea, anemia, weight loss
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24. Global Malabsorption
All nutrient absorption impaired
Classic manifestation:
–Diarrhea- pale, greasy, voluminous, offensive
–Weight loss
Anorexia, flatulence, abdominal distention and
borborygymi
Majority asymptomatic or nonspecific(mimics IBS)
Some nutrient deficiency may predominate (eg.
IDA, osteopenia)
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25. Current spectrum of Malabsorption syndrome in adults in India Pooja Yadav et al
Signs and symptoms Celiac diseaseTS
Abdominal distention 36.1% 23.8%
Vomiting 19.7% 9.5%
Wt loss/FTT 59% 66.7%
Anemia (Hg < 12) 88.5% 52.4%
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26. Partial or Isolated Malabsorption
Attributed to particular nutrient in question:
VitB12: Anemia, parasthesia, Ataxia
Protein: Edema, muscle atrophy, amenorrhea
CHO: watery diarrhea, flatulence, acidic stool PH
General Vit B: Chelliosis, painless glossitis, angular
stomatitis, acrodermatitis
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27. Diagnosis Cont…..
Angular stomatitis
Glositis
( Vit B12, Iron, Folate, Niacin)
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28. Edema and anasarca
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29. Diagnosis
•Is MAS present?
•Is it luminal or mucosal?
•Enteric vs Pancreaticobiliary?
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30. Diagnosis cont……
•Routine battery of blood tests:
–CBC,serum or RBC folate, Vit B12
–Stool examination
–Calcium, Phosphorus, Mg
–Albumin, PT
–Cholesterol, TG,
–Iron, ferritin, TIBC
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31. Diagnosis cont…
Indicator of global malabsorption:
•Fat malabsorption
–Most complex and sensitive to interference
–Quantitative and Qualitative
Quantitative:
–1. Van de Kamer method: A gold standard
•72 hr stool collection on 100 gm fat/d diet
•If > 7 gm/d (usually above 20 gm/day)
•Unable to differentiate as to the cause of steatorrhea
•2. Fecal fat Near infrared reflectance spectroscopy
• analysis (NIRA)
•Uses infrared b/n 1400nM-2600nM
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32. Cont…..
Qualitative:
1. Sudan III staining (sensitivity > 90%)
–Glacial acetic acid separates TG, Stain with Sudan III
–Microscope: large red-orange coloured globules
–Not useful for tropical sprue.
2. Acid steatocrit (galvimetric assay on spot stool)
–Sensitivity 100%, spec 95% and PPV 90%
–After centrifugation add perchloric acid to separate the lipid
–If the content > 10% = abnormal
3. Fecal elastase-1
–Elastase < 200 ug/g stool: Mild PEI
–Elastase < 100 ug/g of stool: Severe PEI
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33. Sudan III fat staining (Magnification
400x)
NEGATIVE POSITIVE
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34. Distinguish enteric from Pancreaticobiliary MAS
D-xylose test: a pentose monosaccharide
•D-xylose 25 gm
–50% metabolized, 50% excreted
•One hour serum D-xylose < 20mg/dl=
Abnormal
•Five hour urine D-xylose < 4gm=
Abnormal
•Limitation:
–Can be affected by bacterial overgrowth
and renal disease
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35. Breath tests
•Lactose H2 breath test: > 20PPM above basal level
–For lactose deficiency: (Bacterial fermentation of
non-absorbable CHO)
•Xylose 1 gm 14 C: > 4.5% at 6 hr
–For bacterial overgrowth syndrome (Catabolized by
gram negative aerobes and absorbed in proximal SI).
•Trioleine 14 CO2 or 13 CO2: < 5.8% in an hour
–For fat malabsorption
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36. Diagnosis cont…
•Protein malabsorption:
–Enteral protein loss: Alpha-1 antitrypsin clearance
–For site of loss: Infusing radio labeled albumin and
gamma camera scintigraphy.
•Vit B12 Malabsorption: Schilling test
–Part one: radio labeled VitB12 alone, 24 hr urine
•If < 10% = abnormal
–Part two: Addition of IF, pancreatic enzyme
–Part three: Administration of antibiotics
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37. Diagnosis cont…
•Abdominal US
–Intestinal wall thickening (CD)
–Dilation of jejunal loops (Celiac disease)
•Barium studies: UGI series
–Small bowel diverticula, anatomic changes
•Endoscopy:
–Cobblestone of duodenal mucosa= CD
–Reduced folds and scalloping of mucosa= Celiac
D.
–Multiple jejunal ulcer=Jujunoileitis or lymphoma
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38. Biopsy
•Small bowel biopsy:
–Endoscopic, Push enteroscopy, during surgery
–Indication:
•Steatorrhea or chronic diarrhea (>3wks)
•Diffuse/focal abnormality suspected on SI series study
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39. Case cont…
•His investigaion was as follows:
–Hgb 10gm/dl with MCV of 96fl
–Alb 1.8gm/dl
–Stool exam ; Giardia cyst
–24 hr fecal fat: 16gm
–Imaging: US and Barium –mildly dialted SI loops
–Endocopy
•Can you consider MAS?
•What specific diagnosis could it be?
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40. Management
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41. Management
Principles of management:
•Identification and treatment of underlying
disease.
•Treatment of diarrhea
•Identification and correction of nutritional
deficit.
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42. Management cont….
Management of diarrhea:
•Non specific antidiarrheal agents: Loperamide,
diphenoxylate with atropine and deoderized
tincture of opium.
•Avoid: caffeine, high sugar containing beverages
like soft drinks and fruit juices or dilute in 1:1
•Use ORS for dehydration and electrolyte
imbalance.
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43. Management cont….
Nutrient supplementation:
•Most have mild to moderate wt loss= continue
with same diet, oral supplement of vitamins and
minerals.
•If deficient= increase daily value by 5-10 x.
•For steatorrhea: polar forms of fat soluble
vitamin replacement- 25-OH Vit D (Calcifediol)
•Iron and folic acid replacement
•Calcium and Mg replacement
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44. Chronic diarrhea
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45. Chronic diarrhea as a major
symptom of MAS
•Definition: Diarrhea
–Frequency > 3 stools per day
–Stool weight > 200 gm per day ( > 300 gm/day
on high fiber diet).
–Consistency: percent of water content (difficult)
•Chronicity:
–> 3-4 weeks, usually non self limiting
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46. Clinically relevant classification
•Watery diarrhea
–Secretory (toxins, endocrinopathies, BAM, IBD, Tu)
–Osmotic(Laxatives, Lact def)
•Inflammatory (Infection, ischemic, IBD, Neoplasms, Rad)
•Fatty diarrhea
–Maldigestion syndrome (PEI, Bile salts)
–Malabsorption syndrome (Celiac, Whipples, SBO,
SBS)
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47. Clinical approach
Question Clinical implication
Abrupt Infections, idiopathic secretory diarrhea
Family history Congenital absorptive defects, IBD, celiac disease, MEN
Weight loss MAS, pancreatic exocrine insufficiency, neoplasm, anorexia
Previous therapeutic interventions
(drugs, radiation, surgery,
antibiotics)
Drug side effects, radiation enteritis, postsurgical status,
pseudomembranous colitis, post-cholecystectomy diarrhea
Systemic illness symptoms Hyperthyroidism, diabetes, vasculitis, tumors, Whipple's disease,
IBD, tuberculosis, mastocytosis
Abdominal pain Mesenteric vascular insufficiency, obstruction, irritable bowel
syndrome
Excessive flatus Carbohydrate malabsorption
Leakage of stool Fecal incontinence03/12/25 47

48. Questions Clinical implication
Stool characteristics
Blood Malignancy, inflammatory bowel disease
Oil/food particles Malabsorption, maldigestion
White/tan color Celiac disease, absence of bile
Nocturnal diarrhea Organic etiology
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49. P/E
•General:
–Nutrition: evidence of malnutrition, micronutrient
deficiencies, Skin flushing, rashes
–fluid balance, vital signs, fever
•Suggestive of IBD
–mouth ulcers, a skin rash, anal fissure or fistula, abdominal
mass
•Evidence of malabsorption
–such as wasting, physical signs of anemia, scars indicating
prior abdominal surgery
•Evidence of HIV infection
•Anal sphincter pressure
•Evidence of hyperthyroidism
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50. Investigation
Blood tests:
CBC (anemia, leukocytosis)
Fluid & electrolytes: creatinine, BUN, Na, K, Cl, Mg, Ca
TSH,
plasma proteins (albumin)
Stool tests:
Stool WBCs, O/P, C Diff
Weight, electrolytes (Na, Cl), osmotic gap
pH: Low (< 6) in carbohydrate malabsorption
Fecal occult blood tests (+ in inflammation, malignancies)
Fat output:
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51. •Fecal leukocyte for inflammatory diarrhea:
–Low specificity : not good test
•Fatty diarrhea:
–Greasy, malodorous stools
–Risk for fat malabsorption: chronic pancreatitis
–Measure stool fat
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53. Management
•Depends on the specific causes
•Empiric therapy
•Fluid and electrolyte
•Nutrition
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54. Summary
•MAS is primarily a decrease in absorption and
is a combination of signs and symptoms.
•Demonstrate disorder of one or more nutrient
absorption.
•Follow systemic approach to sort out the cause
•Management depends on the underlying cause
but always offer supportive care and
symptomatic therapy.
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55. Reading assignment
•Inflammatory Diseases
–emphasis on Crohn’s disease with local and
systemic complications
•Disorders of intestinal motility
•Small bowel obstructions
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