SFP: GI infection and malabsorption Flashcards
(48 cards)
Describe secretory diarrhea
Intestinal cells have a net fluid secretion due to factors like viruses, infections, tumors, or toxins. This persists with fasting.
Describe osmotic diarrhea
Solutes left in the intestines cause excessive osmotic force that pulls fluid into the intestine, usually due to enzyme deficiency (like lactase), and stops with fasting.
Describe exudative diarrhea
Usually due to an inflammatory disease, often autoimmune, resulting in purulent bloody diarrhea. It continues with fasting.
Describe malabsorption diarrhea
Due to enzymatic deficiency or insufficiency that results in products not being broken down and absorbed (ex: steatorrhea). This stops with fasting.
Describe deranged motility diarrhea
Issues with gastric motility due to conditions like short bowel segments post-surgery. It varies in terms of stopping/persisting with fasting.
What defects may lead to malabsorption diseases?
Issues with pancreatic enzymes, defective bile salts, brush-border enzyme deficiencies, nutrient transport issues, and lymphatic transport issues.
What is celiac sprue?
A hypersensitivity to the gliadin portion of gluten.
What are lab findings of celiac sprue?
Anti-gliadin antibodies, anti-endomysial antibodies, and IgA antibodies to tissue transglutaminase.
What is defective in celiac sprue?
Intraluminal digestion and transepithelial transport.
What is the morphology of celiac sprue?
Loss of villi and flat mucosal lesions.
What are mutations associated with celiac sprue?
HLA-DG2 and HLA-DQ8.
What is true of mucosa in celiac sprue?
It has much higher lymphocyte content than normal intestinal mucosa, leading to damaged epithelium that causes malabsorption.
What can celiac disease increase risk for?
Anemia, adenocarcinoma, T cell lymphoma, osteoporosis.
Describe the process of celiac disease
- Gliadin component of gluten attaches to HLA-DQ2 or DQ8 on APC’s.
- APC’s present to T cells, resulting in T and B cell recruitment.
- B cells produce antibodies.
- Hypersensitivity upon introduction of gliadin in the future.
What is tropical sprue?
An enteric dysfunction similar to celiac, caused by environmental or bacterial factors. Morphology is similar but no antibodies are present.
Describe lactase deficiency
A deficiency in lactase prevents the breakdown of lactose in the small intestine, which may be congenital or acquired due to autoimmune diseases or infection.
A breath hydrogen test is used for…
Lactase deficiency.
What is abetalipoproteinemia?
Accumulation of fat in the cytoplasm due to a transport defect, preventing formation of plasma lipoproteins like chylomicrons, VLDL, and LDL.
How does abetalipoproteinemia present?
In infancy with failure to thrive, diarrhea, and steatorrhea.
Spur red cells are seen in…
Abetalipoproteinemia.
What is the presentation of microscopic colitis?
Chronic loose stool with a normal colonoscopy.
What are the two types of microscopic colitis?
Collagenous (thickened collagen layer) and lymphocytic (increased intraepithelial lymphocytes).
Which type of colitis is more associated with celiac disease?
Lymphocytic colitis.
What is graft vs host disease?
A condition in the colon after bone-marrow transplant where donor T cells attack the crypts in the large intestine mucosa.
