Description

• Malabsorption is characterized as a syndrome, as opposed to a disease entity, and is defined as any state in which there is a disturbance of digestion and/or absorption of nutrients across the intestinal mucosa.
• The classical symptoms of malabsorption include chronic diarrhea, abdominal distention, and failure to thrive.

Epidemiology

Depends on the underlying disease causing malabsorption

Etiology

The most common causes of malabsorption in developed countries are as follows:

• Postenteritis syndrome
• Cow’s milk protein intolerance
• Giardiasis
• Celiac disease
• Cystic fibrosis
• Inflammatory bowel disease (IBD)

Pathophysiology

• Depends on the nutrient affected
  • Carbohydrate
    • Monosaccharide: congenital glucose-galactose deficiency, fructose intolerance
    • Disaccharide: lactase deficiency (congenital or acquired), sucrase-isomaltase deficiency
    • Polysaccharide: amylase deficiency (congenital or acquired)
  • Fat
    • Bile salt deficiency: cholestasis, resection of terminal ileum
    • Exocrine pancreatic insufficiency: cystic fibrosis, chronic pancreatitis
    • Inadequate surface area: celiac disease, flat villous lesions
  • Protein
    • Protein-losing enteropathy: intestinal lymphangiectasia, congenital heart failure
    • Exocrine pancreatic insufficiency: cystic fibrosis, Shwachman-Diamond syndrome
    • Inadequate surface area: celiac disease
• According to the place where the alteration occurs
  • Mucosal abnormality
    • Anatomic: post-enteritis syndrome, celiac disease, IBD
    • Functional: disaccharidase deficiencies
  • Luminal abnormality
    • Exocrine pancreatic insufficiency: cystic fibrosis, Shwachman-Diamond syndrome
    • Bile salt insufficiency: biliary cholestatic liver disease, ileal resection
  • Anatomic abnormality
    • Short gut: surgical resection
    • Motility disturbance: intestinal pseudo-obstruction