Malabsorption Syndromes
Saumil K. Shah
Gastroenterologist, Hepatologist, Endoscopist, Lilavati Hospital And Research Centre, Mumbai, India
First Created: 02/20/2001 

Introduction

What is digestion and what is absorption?

Digestion means hydrolysis of nutrients. Absorption means uptake of nutrients from the gastrointestinal tract to the systemic circulation.

What is maldigestion and what is malabsorption?

Maldigestion denotes impaired nutrient hydrolysis. Malabsorption refers to defective mucosal absorption of nutrients. However, the two entities are so closely linked that in clinical practice malabsorption serves as a global term for all aspects of their impairment. Malabsorption may occur for many nutrients or for specific carbohydrates, fats, or micronutrients.

What steps are involved in digestion and absorption?

Three phases are involved:
Luminal phase - Dietary fats, proteins, and carbohydrates are hydrolyzed and solubilized, largely by pancreatic and biliary secretions.

Mucosal phase - Terminal hydrolysis of carbohydrate and peptides occurs and fats are processed and; then packaged for cellular export.

Removal phase - Absorbed nutrients enter the vascular or lymphatic circulation.

Thus defect in any of these phases leads to malabsorption.

What are the Causes of Malabsorption in Children?

Inadequate digestion

  • Postgastrectomy
  • Deficiency or inactivation of pancreatic lipase
  • Exocrine pancreatic insufficiency
  • Chronic pancreatitis
  • Cystic fibrosis
  • Pancreatic insufficiency - congenital or acquired
  • Gastrinoma - acid inactivation of lipase
  • Lactose intolerance

Reduced intraduodenal bile acid concentration/impaired micelle formation

Liver disease

  • Parenchymal liver disease
  • Cholestatic liver disease

Bacterial overgrowth syndrome

  • Anatomic or functional stasis
  • Interrupted enterohepatic circulation of bile salts
  • Ileal resection
  • Crohn's disease

Drugs (bind or precipitate bile salts) : calcium carbonate, neomycin, cholestyramine

Impaired mucosa absorption/mucosa loss or defect

Intestinal resection or bypass

  • Inflammation, infiltration, or infection
  • Celiac disease
  • Crohn's disease
  • Tropical sprue
  • Amyloidosis
  • Scleroderma
  • Lymphoma
  • Immuno proliferative small intestinal disease (IPSID)
  • Eosinophilic enteritis
  • Whipple's disease
  • Folate and Vitamin B12 deficiency
  • Infection: Giardiasis, Strongyloidiasis, Tuberculosis
  • Graft vs. host disease

Genetic disorders

  • Disaccharidase deficiency
  • Agammaglobulinemia
  • Abetalipoproteinemia
  • Hartnup disease
  • Cystinuria

Impaired nutrient delivery to and/or from intestine

Lymphatic obstruction

  • Lymphoma
  • Lymphangiectasia

Circulatory disorders

  • Constrictive pericarditis
  • Vasculitis
  • Congestive heart failure

Endocrine and metabolic disorders

  • Hyperthyroidism
  • Adrenal insufficiency
  • Diabetes mellitus
  • Hypoparathyroidism
  • Carcinoid syndrome

Most Frequent Causes of Malabsorption In Children In India

  • Infections: Giardiasis, Strongyloidiasis, Tuberculosis
  • Celiac sprue (Gluten sensitivity)
  • Lactose intolerance
  • Tropical sprue
  • Chronic pancreatitis
  • Lymphoma, Immunoproliferative small intestinal disease (IPSID)

Does an Acute Gastrointestinal Infection Lead to Malabsorption?

Yes. Acute viral or bacterial gastrointestinal infection can give rise to transient malabsorption, most probably due to damage to small intestinal villi and microvilli.

Where are Specific Food Items Absorbed Along the Gastrointestinal Tract?


Food Item Site of maximal absorption
Proteins
Jejunum and Ileum
CarbohydratesJejunum and Ileum
LipidsJejunum and Ileum
Iron
Duodenum and Jejunum
Calcium
Jejunum and Ileum
Zinc
Duodenum and Jejunum
Magnesium
Small intestine
Vitamin ASmall intestine
Vitamin B12
Ileum
Folic acid
Jejunum
Vitamin C Jejunum and Ileum
Vitamin D Jejunum
Vitamin E Jejunum and Ileum
Vitamin K Jejunum and Ileum
Water Jejunum, Ileum, Colon

When Does One Suspect That a Child has Malabsorption Syndrome?

Progressive weight loss

Failure to thrive

Chronic diarrhea

Steatorrhea

Edema feet

Weakness, Malaise, Fatigue

Abdominal distension

Borborygmi, Excessive flatus

Abdominal pain

Symptoms reflecting specific deficiencies, such as bleeding tendency, muscle cramps, tetany, bone pains and paresthesias

Symptoms related to cause of malabsorption

What Is Steatorrhea?

Steatorrhea is pale, soft, bulky, malodorous stools that stick to the side of the toilet bowl or float and are difficult to flush away. Steatorrhea indicates an excess amount of malabsorbed fat in stools.

What are the Signs in a Child with Malabsorption Syndrome?


Gastrointestinal 
MassTuberculosis,lymphoma, Crohn's disease
DistensionAscites (hypoproteinemia,tuberculosis), pancreatic pseudocyst
Steatorrheicstool
Pancreatic insufficiency, small intestinal mucosa disease
  
Extra intestinal 
Skin 
NonspecificPigmentation, thinning, inelasticity, reduced subcutaneous fat
SpecificPetechiae (Vitamin K deficiency), edema (hypoproteinemia), erythema nodosum (Crohn's disease), dermatitis herpetiformis (celiac sprue)
  
Hair 
Alopecia, thinningGluten sensitivity, generalized inanition
  
Eyes 
Conjunctivitis, episcleritisCrohn's disease
PalenessSevereanemia
  
Mouth 
Aphthous ulcersGluten sensitivity, Crohn's disease
GlossitisDeficiencies ofvitamin B12,iron,folic acidand niacin
Angular cheilosisDeficiencies of vitamin B12, iron, folic acid and vitamin B complex
Dental hypoplasiaGluten sensitivity
  
Hands 
ClubbingGluten sensitivity, Crohn's disease, tuberculosis, lymphoma
KoilonychiaIron deficiency
  
Musculoskeletal 
Mono/polyarthropathyGluten sensitivity, Crohn's disease, Whipple's disease
Back painGluten sensitivity, Crohn's disease
Muscle weaknessDiffuse mucosal disease, lymphoma
  
Nervous system 
Peripheral neuropathyVitamin B 12 deficiency
Cerebral (seizures, dementia, cranial nerve palsies)Whipple's disease, gluten sensitivity, diffuse lymphoma

Why Does Milk And Milk Products Aggravate Diarrhea In Patients With Malabsorption Syndrome?

This occurs since small intestinal mucosal diseases cause secondary lactase deficiency. Lactase is necessary for the digestion of lactose, the disaccharide present in milk.

How to You Initially Investigate Patients with Malabsorption Syndrome?


Blood tests Abnormal result
Complete hemogram, 

Mean corpuscular volume
Anemia Microcytic-Iron deficiency

Macrocytic-Vitamin B12, folic acid deficiency
Peripheral smearHypersegmentation of polymorphic nuclei-Vitamin B12, folic acid deficiency. 

Howell Jolly bodies-Gluten sensitivity, Crohn's disease

Acanthocytes-Abetalipoproteinemia
ESR, C-reactive proteinTuberculosis, Crohn's disease, lymphoma, IPSID, vasculitis
Prothrombin timeVitamin K malabsorption
Serum albuminProtein loss through gut or amino acid malabsorption
Serum calciumVitamin D and calcium malabsorption
Serum phosphateVitamin D malabsorption
Serum alkaline phosphataseVitamin D malabsorption
Serum cholesterolLipid malabsorption
Serum potassium
Increase loss due to excessive diarrhea
Serum iron, serum ferritinIron deficiency
Serum folate, red cell folateFolic acid deficiency
Serum zincZinc deficiency
Serum magnesiumMagnesium deficiency
Serum vitamin B12Vitamin B12 deficiency
Stool-Routine/MicroscopySteatorrhoea, Giardia lamblia, Neutrophils in inflammatory disease
X Ray Abdomen *Calcification (Chronic pancreatitis)
HIV (ELISA) *Human immunodeficiency virus
Thyroid function tests *Hyperthyroidism
Immunoglobulin A *Low immunoglobulin levels
Specific antibodies *Antigliadin (IgA)/Antiendomysial (IgA)-Gluten sensitivity
Sweat chloride *Cystic fibrosis

* Only if clinically suspected

What are the Specific Tests to Evaluate Malabsorption Syndrome?


TestUtility
Schilling testTo evaluate cause of vitamin B12 deficiency
Fecal fat estimationChronic pancreatitis, Small intestinal mucosa disease
Xylose tolerance testSmall intestinal mucosa disease
Small intestinal barium studySmall intestinal mucosa disease
Endoscopy with small intestinal biopsy
Small intestinal mucosa disease
US abdomen, CT scan abdomenChronic pancreatitis, Tuberculosis
ERCPChronic pancreatitis
Tests to evaluate pancreatic exocrine function (Tube and tubeless tests)Chronic pancreatitis
Breath testsBacterial overgrowth syndrome, Lactase deficiency

What are the Basic Principles of Management of Patients with Malabsorption?

Management depends on cause of malabsorption and severity of malabsorption. However, broad guidelines to be followed are:
Nutritional support:

  • Anemia: Hematinic supplements (Iron, Vitamin B12, Folic Acid)
  • Specific deficiencies of vitamins, minerals and trace elements - Oral supplementation (Fat soluble vitamins, calcium, magnesium, zinc, etc.)
  • Temporary lactose restriction for patients with secondary lactase deficiency
  • High-protein, low-fat diet
  • Medium-chain triglycerides preferred as fat substitutes
  • Avoid food items, which aggravate symptoms Symptomatic treatment:
  • Diarrhea: Loperamide or Diphenoxylate
  • Cholestyramine (in patients with limited ileal disease)

Treatment of underlying disease:

Specific therapy for underlying disease is of utmost importance.

  • Celiac sprue: Avoid wheat, barley, rye and oats in diet.
  • Bacterial overgrowth syndrome: Antibiotics.
  • Giardiasis: Metronidazole, Tinidazole, Albendazole
  • Strongyloidiasis: Thiabendazole, Albendazole, Mebendazole, Ivermectin
  • Tuberculosis: Anti tuberculosis therapy
  • Crohn's disease: Aminosalicylates, Corticosteroids
  • Tropical sprue: Antibiotics, Folic acid
  • Chronic pancreatitis: Pancreatic enzymes

What is the Prognosis of a Patient Having Malabsorption?

Once the diagnosis of malabsorption has been made, prognosis primarily depends on the cause of malabsorption. However, once the cause is found, the prognosis is reasonably good in most cases, if medical and diet therapy is rigorously followed. Infectious causes if treated adequately have excellent.

How Long is Therapy Necessary?

It is important to remember that most causes of malabsorption, except infections require continuous supervision by a doctor and necessitate prolonged therapy.


Malabsorption Syndromes Malabsorption Syndromes 02/20/2001
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