Pathology of the Lower GI

Question 1

Celiac, whipple disease giardia

Answer 1

small bowel diseases

Question 2

colitis, IBS, IBD, diverticular disease, appendicitis

Answer 2

large bowel diseases

Question 3

Host factors associated with celiac

Answer 3

Class II HLA-DQ2 or HLA DQ8

type 1 DM, thyroiditis, Sjogren

Question 4

Bulky fatty diarrhea, flatulence, weight loss, anemia, nutritional deficiencies, growth failure in children

Answer 4

Classical presentation of celiac disease

Question 5

Microscopic findings in celiac disease

Answer 5

villous blunting, intraepithelial lymphocytes

Question 6

extra-intestinal complaints with celiac disease

Answer 6

fatigue, Fe deficiency, pubertal delay, short stature, canker sore

Question 7

triad of diarrhea, weight loss, malabsorption

arthritis, lymphadenopathy, neurologic disease

middle-aged or elderly white males

Answer 7

Whipple disease

Question 8

Whipple disease microscopic findings

Answer 8

swollen macrophages –> villi distension

macrophages filled with Whipple bacilli (PAS stain)

Question 9

protozoan parasite –> chronic diarrhea, malabsorption flatulence, weight loss

Answer 9

giardia lamblia

Question 10

Pathology: “schools of fish” in the duodenum

Answer 10

giardia lamblia

Question 11

Pathogenesis of C diff colitis

Answer 11

disruption of normal colonic flora by antibiotic –> C diff overgrowth –> toxins released –> disruption of epithelial cytoskeleton, tight junction barrier loss, cytokine release, apoptosis

Question 12

Histology: pseudomembranes (adherent layer of inflammatory cells and mucinous debris at sites of colonic mucosal injury), denuded surface epithelium, mucopurulent exudates

Answer 12

pseudomembranous colitis

Question 13

most common cause of severe childhood diarrhea and diarrheal mortality worldwide

Answer 13

rotavirus

Question 14

rotavirus pathophysiology

Answer 14

selectively infects and destroys mature enterocytes –> villus surface repopulated by immature secretory cells –> loss of absorptive function –> net secretion of water and electrolytes –> osmotic diarrhea –> dehydration

Question 15

flask-shaped ulcers in cecum mucosa

severe dysentery-like, fulminant colitis

Answer 15

entamoeba histolytica parasitic enterocolitis

Question 16

Stool exam –> ova and parasites

Answer 16

helminth infection enterocolitis

Question 17

Helminthic infections epidemiology

Answer 17

seen in nations with deficient sanitation systems, poor SES and hot, humid climates

Question 18

parasites in tropics, ingested from soil contaminated with feces

Answer 18

roundworm –> obstruction, perforation, growth retardation

Question 19

Histology: focal acute mucosal necrosis or full-thickness necrosis

Answer 19

ischemic colitis

Question 20

normal endoscopy, chronic non-bloody watery diarrhea without weight loss

Answer 20

microscopic colitis

Question 21

Histology: thickened subepithelial collagen layer

Answer 21

collagenous colitis

Question 22

Histology: increased intraepithelial lymphocytes

Answer 22

lymphocytic colitis

Question 23

Population with highest incidence of IBD

Answer 23

Female Ashkenazi Jews

Question 24

Th1 mediated IBD

Answer 24

Crohn’s

Question 25

Th2 mediated IBD

Answer 25

UC

Question 26

Histology: crypt architectural distortion (chronic), cyptitis, crypt abscess

Answer 26

active chronic colitis (IBD)

Question 27

outpouchings lined by mucosa, submucosa and variable amounts of muscularis propria

Answer 27

diverticulosis

Question 28

diverticulitis histology

Answer 28

diverticulum becomes infiltrated with acute, then chronic inflammatory cells

extension of infection –> mucosal ulceration, pericolonic abscesses, fistulas

Question 29

appendicitis histology

Answer 29

mucosal ulceration, transmural acute and chronic inflammation, extension of inflammation into the mesoappendix