Malabsorption syndrome

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Malabsorption
syndrome
By:
Dr. Elias S.
Dr. Maruf A
Malabsorption

Impaired absorption of one or more
dietary nutrients


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:



A pathophysiologic state with multiple
etiologies/varied clinical manifestations
Primary (congenital defects)
Secondary (acquired defects)
Clinical Sx usually due to:


Malabsorption of fat &/or carbohydrate
(with water & electrolyte Mal.)
Steatorrhea  main feature in most cases
Nutrient
malabsorption
Intestinal
secretion
Diarrhea
Steatorrhea
Watery D.
Inflammatory D.
Inflammation
mechanisms
1.
Luminal phase (processing defect)




2.
Mucosal phase


3.
Digestive enzyme deficiency / inactivation
bile salt synthesis; Excretion; loss;
bile salt de-conjugation
gastric acid; intrinsic factor (p. anemia)
Bacterial consumption of nutrients
Epithelial transport defect – inflammations
infections
Brush border hydrolysis defect
congenital/acquired disacharidase deficiency
Post-absorptive phase


Enterocyte processing – Abetalipoproteinemia
Lymphocytic obstruction – intestinal
lymphangectasia
causes
Exocrine pancreatic insufficiency
ch. Pancreatitis
pancreatic CA
cystic fibrosis
Inactivation of pancreatic
lipase – Gastrinoma(ZES)
drugs (orlistat)
bile acid (impaired
micelle formation)
parenchymal liver D.
cholestatic liver D.
Bacterial overgrowth
Anatomic stasis
(blind loop,stricture,fistula)
Functional stasis
(DM, scleroderma)
Interrupted interohepatic
circulation of bile acid
(ileal resection, crohn’s D.)
Drugs(bind or precipitate bile salt)
neomycin, chlestyramine
Impaired mucosal absorbtion/
mucosal loss or defect
intestinal resection or bypass
inflammation/infiltration/infect.
(celiac sprue, tropical sprue,
whippl’s disease, lymphoma,
mastocytosis, eosinophilic e.,
scleroderma, crohn’s D., …)
Impaired nutrient transport
lymphatic obstruction
(lymphoma, lymphangectasia)
CHF
Genetic disorders
disacharidase defficiency
Agamaglobulinemia
Abetalipoprotinemia
Endocrine/Metabolic disorders
DM
Hyperthyroidism
adrenal insufficiency
carcinoid syndrome
Clinical features
Depend on the cause and severity

Glabal
Diffuse mucosal
involvement
 Impaired absorption of
all nutrients
 Classic manifestation
Diarrhea(steatorrhea)
weight loss
 Majority – sub clinical
E.g.. Celiac disease


Partial (isolated)

2° to diseases that
interfere with
absorption of specific
nutrients
E.g.Pernicious Anemia
Lactase deficiency
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
Clinical Evaluation

In 75-80% of cases
• Dx by expert Hx & P/E + focused lab tests

25% - need extensive study/ Hospitalization

Hx: • Diarrhea- duration, consistency, frequency
stool characteristics, Volume
time of occurrence, association
with diet etc….
• Bloating,borborigmi, flatus
• Abdominal pain
• Sxs of extra intestinal manifestation (joint pain, mouth ulcer..)
• Previous abd. Surgery
• medication
• Alcohol intake
• Recurrent PUD
• DM , CLD
• Falmily Hx – celiac disease, crohn’s D.)
• Risk factors – HIV infection
 P/E – thorough examination
Look for
signs of specific nutrient Malabsorption
extraintestinal signs
 Lab.
 CBC, PT, serum protein, ALP



Checks for depletion of iron,folate, B12, Vit D, Vit K)
RFT,electrolytes
Stool exam
Additional tests:
 Serum carotene, cholesterol, albumin, iron, folate
cobalamine
Tests for steatorrhea

Quantitative test

72hr stool fat collection – gold standard
• > 6gm/day – pathologic
• P’ts with steatorrhea - >20gm/day
• Modest elevation in diarrheal disease
(may not necessarily indicate Malabsorption)

Qualitative tests

Sudan lll stain
• Detect clinically significant steatorrhea in
>90% of cases

Acid steatocrit – a gravimetric assay
• Sensitivity – 100%, specificity – 95% , PPV – 90%

NIRA (near infra reflectance analysis)
• Equally accurate with 72hr stool fat test
• Allows simultaneous measurement of fecal fat, nitrogen,
CHO
Schilling test


To determine the cause of cobalamine(B12)
malabsorbtio
Helps to asses the integrity of gastric, pancreatic and
ileal functions.
• Abnormal cobalamine absorbtion in:
pernicious anemia, ch. Pancreatitis, Achlorohydria, Bacterial
overgrowth, ileal dysfunction

The test
• Administering 58Co-labeled cobalamine p.o.

Cobalamine 1mg i.m. 1hr after ingestion to saturate hepatic
binding sites
• Collecting urine for 24 hr
(dependant on normal renal & bladder function)
• Abnormal - <10% excretion in 24 hrs
Schilling test cont….
58CoCbl
Pernicious
Anemia
Chronic
Pancreatitis
Bacterial
overgrowth
Ileal
disease

With
With
5 Days
Intrinsic pancreatic Of Ab
factor
enzyme
N




N




N




D-xylose test

D-xylose



A Pentose monosacharide absorbed
exclusively at the proximal SB
Used to asses proximal SB mucosal function
The test




After overnight fast, 25gm D-xylose p.o.
Urine collected for next 5 hrs
Abnormal test - <4.5 gm excretion
show duodenal / jejunal mucosal D.
False +ve results: Renal dysfunction
Inadequate urine sample
Impaired gastric empyting, ascitis
Drugs(ASA,indometacin, Neomycin)

Othe tests for carbohydrate malabsorbtion

Lactose tolerance test
• P.o. 50gm lactose
• Bloood glucose at 0,60,120 min.
• BG <20mg/l + dev’t of Sxs – diagnostic


Breath tests (hydrogen,4Co2,13Co2)
Test for bacterial overgrowth


Tests for pancreatic insufficiency



Quantitative bacterial count from aspirated
SB. Normal count: < 10 /ml (jejunum)
> 10 /ml (ileum)
Stimulation of pancreas through adm. Of a meal
or hormonal secretagogues , then analysis of duodenal
fluid
Indirect tests – schilling test
Tests for protein malabsorption
Enteral protein loss  measuring alpha-1 antitirypsin clearance
Endoscopy

Gross morphology – gives diagnostic clue


Cobblestone appearance – crhon’s D.
Reduced duodenal folds and scallopng
of duodenal mucosa – celiac disease
• Use of vital dyes to identify villous atrophy

Biopsy – to establish Dx


Lesions seen – classifid in to three




For p’ts with documented steatorrhea
or ch. Diarrhea
Diffuse,specific e.g. whippl’s Disease
Patchy, specific – crohn’s D., lymphoma
infectious causes
Diffuse,non-specific – celiac sprue, Tropical sprue
autoimmune enteropathy
Suspected distal pathology - push enteroscopy
wireless capsule endoscopy
Barium studies
 Important
information about the gross
anatomy and morphology of SB


Upper GI series with SB follow through
Enteroclysis
• double contrast study by passing a tube into
proximal SB and injecting barium+ methylcellulose
 Normal
study doesn’t exclude SB disease
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