Small Intestine and Colon

Question 1

symptoms of acute colonic ischemia

Answer 1

• sudden onset of cramping
• Left lower abdominal pain (Right sided ischemia is WORSE)
• a desire to defecate
• bloody diarrhea (no signif blood loss)

Question 2

angiodysplasia

Answer 2

-lesion of malformed submucosal and mucosal blood vessels, usually in cecum or Right colon

Question 3

4 parts of digestion

Answer 3

1. intraluminal digestion
2. terminal digestion
3. transepithelial transport
4. lymphatic transport of absorbed lipids

Question 4

4 types of diarrhea

Answer 4

1. secretory (isotonic stool, continues with fasting)
2. osmotic (lactase deficiency, excessive osmotic forces due to unabsorbed luminal solutes, >50 mOsm, stops with fasting)
3. malabsorptive (general failure of nutrient absorption, associated with steatorrhea, stops with fasting)
4. exudative (due to inflammatory disease with purulent, bloody stool, continues with fasting)

Question 5

what does gliadin do?

Answer 5

• it contains most of the disease producing parts for celiac
• gliadin peptides induce epithelial cells to express IL-15 which activates and prolif CD8+lymphocytes which express NKG2D, leading to tissue damage
• gliadin peptides also interact with HLA-DQ2 and HLA-DQ8 on APC, which stimulates CD4+ cells to produce cytokines, causing more tissue damage

Question 6

HLA-DQ2, HLA-DQ8

Answer 6

-exist as class 2 alleles in people with celiac (about 1/2 of the genetic part of celiac disease)

Question 7

symptoms of celiac disease?

Answer 7

• chronic diarrhea, bloating, fatigue, or asymptomatic
• pediatric, may also have malabsorption
• dermatitis herpetiformis in 10% of pts
• Dx: IgA antibodies to tTG (tissue transglutaminase)
• celiac= higher risk of malignancies

Question 8

autoimmune enteropathy

Answer 8

-X linked, severe persistent diarrhea and autoimmune disease, most often in young kids
-severe familial form= IPEX
-germline mutation of FOXP3 (transcription factor on the X chromosome
Tx: immunosuppression

Question 9

Lactase/disaccharide Deficiency

Answer 9

• has congenital and acquired (usually after an enteric viral or bacterial infection) types
• issue with terminal digestion

Question 10

abetalipoproteinemia

Answer 10

-rare, AR, unable to secrete triglyceride rich lipoproteins due to MTP mutation, leads to intracellular lipid accumulation
-issue with transepithelial transport
Sx: presents in infancy, failure to thrive, diarrhea, steatorrhea, deficiency of Fat-soluble vitamins

Question 11

symptoms of infectious enterocolitis

Answer 11

-diarrhea, abdominal pain, urgency, perianal discomfort, incontinence, hemorrhage (broad range!)