Malabsorptive Diseases Flashcards
Malabsorption
Poor transport of micronutrients from the gut into the body
What is the role of the brush border enzymes?
Carbohydrates broken down by brush border enzymes into simple sugars
What does the absence of brush border enzymes cause?
Absence of brush border enzymes causes one of the most common malabsorption disorders—lactose intolerance; generalized loss also seen after infection
What will cause malabsorption in the small intestine?
Absence of transporters, mucosal infiltration (amyloid), inflammation (celiac), obstruction of venous or lymphatic outflow will cause malabsorption
Medium Chain Triglycerides
- No bile salts, lipase, colipase, ileum required with direct absorption across mucosa to portal vein
- Useful in short gut syndrome & fat malabsorptive disorders
What are the limitations of MCT?
- Doesn’t contain essential fatty acids – EFA deficiency
- Excess metabolized to ketones – Metabolic acidosis
What is mainly absorbed in the duodenum?
Calcium and iron
What is mainly absorbed in the jejunum?
Most nutrients - carbs, fat and protein
What is mainly absorbed in the ileum?
Vitamin B12 and bile salts
Why are jejunal losses well tolerated?
Jejunal losses are well tolerated b/c ileum adapts to provide absorption - ileal losses are NOT well tolerated though.
What nutrient absorption is affected in celiac disease?
Iron, folate, calcium, Vit D malabsorption (osteopenia) is common - vitamin B12 malabsorption from celiac is RARE
What are general lab tests for suspected malabsorption?
- Basic Chemistries and Blood Count
- Micronutrient Absorption Studies
What is the function of the fecal elastase test?
Fecal Elastase or Chymotrypsin (marker of pancreatic exocrine function, decreased in pancreatic insufficiency)
