17-5 -- Malabsorption Flashcards
What is a stool sign of malabsorption?
Steatorrhea
Steatorrhea
Fatty, greasy, stools
- sign of malabsorption
Diarrhea can occur due to what 4 mechanisms being impaired?
- Intraluminal digestion
- Terminal digestion
- Transepithelial Transport
- Lymphatic Transport
Diarrhea can occur due to what 4 mechanisms being impaired?
- Intraluminal digestion
- Terminal digestion
- Transepithelial Transport
- Lymphatic Transport
What is absorbed with Intraluminal digestion and what 3 conditions is it impaired with?
Breakdown of carbs, fats and proteins
= IBD, Pancreatitis and Cystic Fibrosis
What is absorbed with Lymphatic Transport and what condition is it impaired with?
Lipid absorption
= Whipple disease
Increased stool mass/frequency/fluidity > 200 mg per day
Diarrhea
4 types of Diarrhea?
- Secretory
- Osmotic
- Malabsorptive
- Exudative
4 types of Diarrhea?
- Secretory
- Osmotic
- Malabsorptive
- Exudative
Isotonic diarrhea; persists during fasting
Secretory Diarrhea
Diarrhea fluid is more concentrated than plasma; stops with fasting
Osmotic Diarrhea
Steatorrhea diarrhea; relieved by fasting
Malabsorptive Diarrhea
Purulent, bloody diarrhea due to inflammatory disease; persists during fasting
Exudative Diarrhea
How does Cystic Fibrosis cause diarrhea?
- pancreatic abnormalities that cause an accumulation of mucous
- Impaired secretions = impaired digestion
What may be seen in a child with Cystic Fibrosis that causes a bowel obstruction?
Meconium Ileus
What is an immune disease triggered by the ingestion of gluten?
Celiac disease
Describe the pathogenesis of Celiac Disease
- Gluten broken down to Gliadin
- Gliadin induces cells to express IL-15
- IL-15 triggers CD8+ T cell activation
- T cells express NKG2D
- NKG2D recognizes MIC-A on enterocytes and T cells attack
What HLA molecules does Gliadin interact with to cause more tissue damage with Celiac Disease?
HLA-DQ2 and HLA-DQ8
What physical changes to the intestines are seen with Celiac Disease?
Villous atrophy
Crypt hyperplasia
Loss of mucosal surface area
What cell type is increased intraepithelially with Celiac Disease?
Lymphocytes
Celiac disease involves IgA antibodies. What specific antibodies can diagnose Celiac disease?
EMA
tTG
EMA and tTG antibodies can diagnose?
Celiac Disease
What are some classic symptoms of Celiac Disease?
Diarrhea and bloating
Malabsorption which causes Anemia
Dermatitis Herpetiformis (blisters from IgA deposits)
What are some classic symptoms of Celiac Disease?
Diarrhea and bloating
Malabsorption which causes Anemia
Dermatitis Herpetiformis (blisters from IgA deposits)
Those with Celiac disease have an increased risk for what malignancy?
T cell lymphoma
What causes Environmental Enteropathy?
Poor sanitation/hygiene or
Defective mucosal immune function
3 symptoms of Environmental Enteropathy?
Malabsorption
Malnutrition
Stunted growth
Malabsorption and stunted growth are seen with which Enteropathy?
Environmental Enteropathy
How is Autoimmune Enteropathy inherited?
X-linked Recessive
Autoimmune Enteropathy involves loss of?
FOXP3
==> defective development of CD4 T REG cells
Autoimmune Enteropathy involves loss of?
FOXP3
==> defective development of CD4 T REG cells
Autoimmune Enteropathy involves antibodies to what cells?
Enterocytes
Goblet cells
Parietal cells
Islet cells
What cell type infiltrates the intestinal mucosa with Autoimmune Enteropathy?
Neutrophils
What are the symptoms of Autoimmune Enteropathy?
Persistent diarrhea
Autoimmune disease
** in CHILDREN **
What age group does Autoimmune Enteropathy primarily affect and what are the symptoms?
CHILDREN
- Persistent diarrhea and autoimmune disease
With Abetalipoproteinemia, what can the body NOT make?
Unable to assemble triglyceride-rich lipoproteins
With Abetalipoproteinemia, what can the body NOT make?
Unable to assemble triglyceride-rich lipoproteins
Abetalipoproteinemia involves a mutation in?
MTP
With Abetalipoproteinemia, where do lipids accumulate?
Intracellularly
Symptoms of Abetalipoproteinemia and when it presents?
Presents in INFANCY
= failure to thrive, diarrhea, steatorrhea
Symptoms of Abetalipoproteinemia and when it presents?
Presents in INFANCY
= failure to thrive, diarrhea, steatorrhea
What 4 molecular things are seen with Abetalipoproteinemia?
NO apolipoprotein B
Decreased Vitamins
Acanthocytes
Spiky RBCs
What 4 molecular things are seen with Abetalipoproteinemia?
NO apolipoprotein B
Decreased Vitamins
Acanthocytes
Spiky RBCs
Describe how diarrhea arises with Lactase Deficiency
Lactose cannot be converted to glucose + galactose
= Lactose remains in lumen and attracts fluid
== Diarrhea
2 types of Lactase Deficiency?
Congenital
Acquired
Congenital Lactase Deficiency
Mutation in gene encoding lactase
Symptoms of Congenital Lactase Deficiency?
When milk ingested in infancy:
= explosive diarrhea and abdominal distention
Acquired Lactase Deficiency?
Downregulation of lactase gene expression due to not ingesting milk after weaning or infections
Symptoms of Acquired Lactase Deficiency?
Diarrhea and flatulence
Milk ingested in infancy which causes explosive diarrhea and abdominal distention is likely?
Congenital Lactase Deficiency
