2 Disease of lower GI: path - [3] deveraj Flashcards
pathogenesis of Celiac disease (gluten sensitive enteropathy)
Gluten digested by luminel + brush border enzymes →
exposure to α-gliadin peptide results in autoAb formation →
inflammation (↑ T lymph) →
villous atrophy →
tissue damage →
loss of mucosal and brush border surface area →
malabsorption, diarrhea
classical presentation of celiacs
bulky fatty diarrhea flatulence weight loss anemia nutritional deficiencies growth failure in children
3 characteristic findings in tissue biopsy for Celiacs
Endoscopy findings?
- villous blunting
- increased intraepithelial lymphocytes
- lymphoplasmacytosis of the lamina propria
scalloped appearance (*note: IgA ab to TTG and anti-endomysial ab)
celiacs disease is associated with the blistering skin disease _____
dermatitis herpetiformis
Pathogenesis of Whipple disease
caused by gram (+) bacilli Tropheryma whippelii
- bacilli absorbed by lamina propria macrophages →
organism-laden mac. accumulate in sm Int lamina propria + mesenteric lymph nodes → lymphatic obstruction →
malabsorptive diarrhea
“foamy macrophages”
clinical features of whipple disease
triad of:
diarrhea, weight loss, malabsorption
typically in middle ages or elderly white males
Giardia lamblia
- what
- dx
- sx
- tx
protozoan parasite
waterborne + Cl resistant
dx: trophozites or cysts (cute purple smiley guy)
sx: bloating, flatulence, foul smelling fatty diarrhea
tx: metronidazole
Infectious enterocolITIS
- bacterial infections
typically create an acute self-limited colitis
pts usually present several weeks after onset of sx, so tisue biopsy rarely shows classic acute infectious findings
- campylobacter
- shigellosis
- salmonellosis
- E. coli
Campylobacter spp
- Gram ___
- usually found ____
- Presentation
gram NEGATIVE major cause of diarrhea worldwide
a leading cause of bacterial foodborne illness in US
- found in contaminated meat (poultry), water, and unpasteurized dairy
Prod. WATERY diarrhea +/- blood
Infectious enterocolITIS
Salmonella
- Gram ___
- usually found ____
- Presentation
- Characteristic pathology most commonly seen in:
gram NEGATIVE food and water - food poisoning + travelers diarrhea - typhoid mary Prod diarrhea @ 2nd week of infxn initially watery then bloody ileum, colon, appendix, Peyer's patches
Infectious enterocolITIS
Enterohemorrhagic E. Coli pathology sx endoscopy area of colon affected
[O157:H7] “jack in the box”
non invasive, toxin producing, contaminated hamburgers
bloody diarrhea, severe cramps, mild or no fever, renal failure maybe
Pseudomembranous colitis
- commonly caused by
- susceptibility factor?
- sx?
- type of diarrhea?
C. diff colitis often occurs after course of antibiotic therapy "antibiotic associated colitis" - 3rd gen cephalosporins common in hospitalized pts
sx: fever, leukocytosis, abdominal pain, cramps, watery diarrhea
which virus is the most common cause of severe childhood diarrhea and diarrheal mortality worldwide?
- path?
rotavirus
- children 6-24 mo vulnerable
infects and destroys mature enterocytes →
villus surface repopulated by immature secretory cells →
loss of absorptive fxn →
net secretion of water and electrolytes →
osmotic diarrhea →
DEHYDRATION
2 vaccines now available
Indiv at risk for ischemic colitis
older indiv w/ co-existing cardiac or vascular disease
young pts: long distance runners, women on oral con.
mech. obstruction: hernias, volvulus
- splenic flexure + rectosigmoid area at risk (watershed)
presentation of ischemic colitis
acute transmural infarction → severe abdominal pain tenderness n/v bloody diarrhea PERISTALSIS SOUNDS DISAPPEAR rigid abdomen shock/sepsis
