THE INS AND OUTS OF
MALABSORPTION SYNDROME
Brent J. Shriver, PhD
Associate Professor and Academic Coordinator
Department of Physician Assistant Studies
The University of Texas Health Science Center at
San Antonio
Malabsorption Syndrome
• Impaired absorption of nutrients
• Caused by abnormalities in either
digestion or absorption
• Can be centered in any organ or tissue
involved in digestion or absorption
• Often hard to classify
Maldigestion versus Malabsorption
• Maldigestion: failure of chemical
processes of digestion to occur in the
intestinal lumen or brush border.
• Malabsorption: failure of the intestinal
mucosa to absorb or release (transport) the
digested nutrients.
Causes of Malabsorption Syndrome
• Maldigestion
• Deficiency of enzymes
• Inadequate pH optimum
• Lack of bile acids
• Inadequate acid or bicarbonate
• Resection
• Bacterial overgrowth
• Malabsorption
• Mucosal disruption
• Vascular disorders
• Intestinal disease
• Dysmotility
• Bacterial overgrowth
Pathogenesis of Lipid Malabsorption
• Occurs more often than for other nutrients
• Effects are also more severe
• Pancreatic insufficiency is a major cause
• Results in steatorrhea
• Hydroxylation of the undigested fat by bacteria in
the colon can result in diarrhea
• GI tract abnormalities that decrease absorptive
surface
• Abnormalities in the accessory organs of the
digestive system
Lipid Malabsorption, cont.
• Stasis or recirculation of intestinal
contents
• Bacterial overgrowth
Pathogenesis of Carbohydrate Malabsorption
• Less common than lipid malabsorption
• Deficiency or absence of pancreatic
carbohydrases
• Deficiencies of intestinal carbohydrases
Malabsorption of Other Nutrients
• Protein
• Deficiencies in either pancreatic or intestinal
enzymes
• Extent of malabsorption and the severity of the
consequences are lower
• Vitamin B12
• Occurs for a number of reasons
• Deficiency of intrinsic factor
• Metabolism of the vitamin in the GI tract
Clinical Features of Malabsorption
Syndrome
• Depend on the cause and severity of the disease
• Can be classified as either global or isolated
• Global malabsorption syndrome is caused by
diseases that significantly reduce overall absorptive
capacity
• Isolated malabsorption syndrome is caused by
diseases that affect absorption of individual nutrients.
• Global malabsorption syndrome is more likely to
cause early clinical symptoms
• Symptoms of global malabsorption syndrome are
typically mild and non-specific
Clinical Features, cont.
• Global malabsorption syndrome can trigger more
severe symptoms
• Diarrhea
• Steatorrhea
• Weight loss
• Symptoms of isolated malabsorption syndrome
are related to the specific nutrient being
malabsorbed
Diagnosis of Malabsorption Syndrome
• Detailed patient history
• Blood tests
• Fecal testing
• Abdominal ultrasound
• Endoscopy
• Pancreatic imaging
Tests for Fat Malabsorption
• Fecal fat testing
• Sudan III stain
• Near infrared reflectance analysis
• Acid steatocrit
• 14C-triolein breath test
Tests for Carbohydrate Malabsorption
• D-xylose test
• Lactose tolerance test
• Breath tests
Tests for Protein Malabsorption
• Alpha-1 antitrypsin clearance
• Plasma citrulline and arginine concentrations
Other Tests for Malabsorption Syndrome
• Schilling test
• SeHCAT test
• Tests for bacterial overgrowth
• Tests for pancreatic insufficiency
THE INS AND OUTS OF
MALABSORPTION
SYNDROME
The End
Questions?