MALABSORPTION MALABSORPTION SYNDROMESYNDROME

Prof. Saleh M. Al-AmriProf. Saleh M. Al-AmriConsultant, Gastroenterology UnitConsultant, Gastroenterology Unit

College of Medicine & K.K.U.H.College of Medicine & K.K.U.H.King Saud UniversityKing Saud University

MALABSORPTION SYNDROMEMALABSORPTION SYNDROME

This occurs when the normal digestion and absorption of food is interrupted.

PATHOPHYSIOLOGICAL (MECHANISM):

-Is divided into:

A) Intraluminal stage

Impaired hydrolysis and solubilization of nutrients in the small intestine.

1 (Impaired fat absorption:

i) Pancreatic lipase is necessary for triglyceride hydrolysis in duodenum.

Pancreatic enzyme deficiency leads to fat malabsorption.

ii) Inactivation of pancreatic lipase by low gastric luminal

pH – fat malabsorption.

iii) Interruption of enterohepatic circulation of bile salt – impaired micelle formation – fat malabsorption.

Absorption of fat soluble vitamins may be impaired as well.

2 (Impaired carbohydrate absorption:

Most diseases that causes carbohydrate malabsorption do so by affecting intestinal stage.

But amylase catalyse hydrolysis of starch to

oligosaccharides .

3 (Impaired protein absorption:

Hydrolysis of polypeptides occurs mainly in small intestine by action of pancreatic enzyme trypsin, chymotrypsin.

Deficiency of pancreatic proteases – impaired protein absorption.

Diseases like :

Chronic pancreatitis

Cystic fibrosis

Ca. pancreatic resection

- Protein malnutrition

B) Intestinal stageB) Intestinal stage

1 (Abnormalities of small intestinal mucosa.

Lactase deficiency

e.g. Congenital or acquired

Result – malabsorption of lactose.

Acquired:- i) Coeliac disease

ii) Crohn’s disease

iii) Infective enteritis

2 (Impaired epithelial cell transport:

Many diseases cause loss of intestinal surface area

- malabsorption of many nutrients.

e.g. i) Coeliac disease

ii) Tropical spure

iii) Extensive surgical resection

iv) Drugs

C) Lymphatic transportC) Lymphatic transport::

Lymphatic obstruction – fat malabsorption

e.g. i) Intestinal lymphangiectasia

iii) Tuberculous enteritis

iv) Intestinal lymphoma

D)D) Decreased availability of ingested nutrients and

cofactors for absorption.

i) Vitamin B12 malabsorption if intrinsic factor is deficient. e.g. gastrectomy, antiparietal cell Ab.

ii) Bacterial overgrowth –can bind B12.

iii) Patient infected with fist tapeworm – B12 deficiency.

CLINICAL MANIFESTATIONS

History:

Diarrhea/steatorrhoea Weight loss Symptoms of anaemia

Diarrhoea – bulky, floating, malodorous stool – difficult to flush .

Weight loss – may be profound, usually associated with anorexia .

Anaemia – B12, iron, folate malabsorption.

Patient may complain of dizziness, dyspnoea and fatigue

Important part of history:

Recent travel - giardiasis

Drug abuse/multiple blood transfusions or ethanol

abuse

surgical resection

- small bowel

- gastric

Malabsorption + chronic lung disease = cystic fibrosis

Fever + weight loss = TB, lymphoma.

O/E:

Normal.

Pallor - muscle wasting

Sign of vitamin deficiency

glossitis – B deficiency

ecchymoses

parasthesia

tetany

Investigations:

General:

- CBC

- Blood film

- Ca.

- B12, folate

- Iron study

- LFT, PT, PTT

Investigations:

Specific:

Tests of fat absorption:

Quantitative fecal fat

Patient should be on daily diet containing 80-100 grams of fat.

Fecal fat estimated on 72 H collection.

6 grams or more of fat/day is abnormal.

May be due to: - Pancreatic

- Small intestinal

- Hepatobiliary disease

1414C-Triolein TestC-Triolein Test::

Is triglyceride which is hydrolysed by pancreatic lipase .

absorption of metabolism ↑ 14CO2

lung

Tests for pancreatic function:

1 (Bentiromide test:

Chymotrypsin

PABA + pepside

PABA absorbed and conjugated in liver

urine excretion

2 (Schilling test

3) Pancreatic stimulation test Secretin stimulation –

4) Radiographic techniques: - Plain abdominal X-ray - U/S abdomen - ERCP - CT abdomen

Carbohydrate absorption test

1 (Hydrogen breath test

Hydrogen excretion ↑ in

bacterial overgrowth

small intestinal malabsorption

Carbohydrate absorption test

2 (D-xylose test

5-carbon sugar excreted unchanged in urine

25 grams given

Urine collected for 5 hours

Normally 25% is excreted

In patients with fat malabsorption, this test

differentiates pancreatic from small intestinal malabsorpton.

D-xylose is normal in pancreatic disease

Serum level of D-xylose at 1-2 hours after ingestion can be measured .

Test for bacterial overgrowth:Test for bacterial overgrowth:

1)1) Intestinal aspiration and cultureIntestinal aspiration and culture

2)2) Breath testBreath test

3)3) C-D xylose breath testC-D xylose breath test

1)1) Radiography of small intestine:Radiography of small intestine:

Barium swallow and follow-through – to Barium swallow and follow-through – to seesee

- Blind loop- Blind loop

- Stricture- Stricture

- J. diverticular- J. diverticular

2)2) Intestinal mucosal biopsy:Intestinal mucosal biopsy:

- using crossby capsule- using crossby capsule- endoscopy- endoscopy

Coeliac disease:Coeliac disease:- Villous atrophy- Villous atrophy

Tropical spure:Tropical spure:- short villi and increased lymphocyte- short villi and increased lymphocyte

Selection of tests in evaluation malabsorption

Quantitaive fecal fatQuantitaive fecal fat

Normal Abnormal

D-xylose test

Normal Abnormal

Abd. Radiograph14 C-D-xylose test

Bentiromide test

CT-abd. Normal

Small intestinal Bx

Abnormal

• Jej culture

• Tetracyclin

•Then repeat breath test

Classification of Malabsorption Classification of Malabsorption SyndromeSyndrome

A.A. Inadequate digestion:Inadequate digestion:• Postgastrectomy steatorrhea.Postgastrectomy steatorrhea.• Exocrine Pancreatic insufficiency.Exocrine Pancreatic insufficiency.• Reduced bile salt concentration in Reduced bile salt concentration in

intestine:intestine:I.) Liver DiseaseI.) Liver Disease

II.) CholestasisII.) Cholestasis

III.) Bacterial over growthIII.) Bacterial over growth

IV.) Interruption of enterohepatic circulation of IV.) Interruption of enterohepatic circulation of bile salt.bile salt.

B.B. Inadequate absorptive surface:Inadequate absorptive surface:• ResectionResection• Diseased intestineDiseased intestine

C.C. Lymphatic obstruction.Lymphatic obstruction. e.g Lymphomae.g Lymphoma

D.D. Primary mucosal defects. Primary mucosal defects.• Crohn’s diseaseCrohn’s disease• Coeliac diseaseCoeliac disease• Tropical SprueTropical Sprue• Disaccharide DeficiencyDisaccharide Deficiency• LymphomaLymphoma• TBTB

Malabsorption due to bacteral over Malabsorption due to bacteral over growth of small bowelgrowth of small bowel

Normal small intestine is bacterial sterile due to: Normal small intestine is bacterial sterile due to:

AcidAcid Int. peristalsis (major)Int. peristalsis (major) ImmunoglobulinImmunoglobulin

Cause of bacterial growth.Cause of bacterial growth. e.g.e.g.

Small intestinal diverticuliSmall intestinal diverticuli Blind loopBlind loop StricturesStrictures DM/ SclerodermaDM/ Scleroderma

PathophysiologyPathophysiology

1)1) Bacterial over growth: Metabolize bile salt Bacterial over growth: Metabolize bile salt resulting in deconjugation of bile salt resulting in deconjugation of bile salt

Bile SaltBile Salt Impaired intraluminal micelle formationImpaired intraluminal micelle formation Malabsorption of fat. Malabsorption of fat.

2)2) Intestinal mucosa is damaged byIntestinal mucosa is damaged by Bacterial invasionBacterial invasion ToxinToxin Metabolic productsMetabolic products Damage villi Damage villi may cause total villous atrophy. may cause total villous atrophy.

Clinically:Clinically: SteatorrheaSteatorrhea AnaemiaAnaemia B12 def.B12 def.Reversed of symptom after antibiotic Reversed of symptom after antibiotic

treatment.treatment. Diagnosis:Diagnosis: Breath testBreath test Cxylose testCxylose test Culture of aspiration (definitive)Culture of aspiration (definitive)Treatment:Treatment: Antibiotic Antibiotic TetracyclinTetracyclin CiproflexacinCiproflexacin MetronidazoleMetronidazole AmoxilAmoxil

Intestinal LymphomaIntestinal Lymphoma

Primary 2Primary 2ndnd Affect male = 50 Y.Affect male = 50 Y. Feature of malabsorptionFeature of malabsorption Biopsy resemble coeliac sprue Biopsy resemble coeliac sprue Abdominal painAbdominal pain FeverFeverIncomplete respond to gluten free diet.Incomplete respond to gluten free diet.Absent features of generalized lymphoma.Absent features of generalized lymphoma.

Malabsorption may be due to:Malabsorption may be due to: Diffuse small intestinal mucosa disease.Diffuse small intestinal mucosa disease. Obstruction of lymphatic channelsObstruction of lymphatic channels Stenosis Stenosis bacterial overgrowth. bacterial overgrowth. FeverFever

Diagnosis:Diagnosis: History/Endoscopic Biopsy - History/Endoscopic Biopsy - CT scan of abdomenCT scan of abdomen LaparotomyLaparotomySome form secretion Some form secretion - heavy chain - heavy chain Ig A.Ig A.

Complication:Complication: PerforationPerforation BleedingBleeding Intestinal obstructionIntestinal obstruction

Treatment:Treatment: Chemotherapy Chemotherapy SurgerySurgery