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Flashcards in Bowel Path II Deck (54):
1

most common cause of severe diarrhea in infants and young children

rotavirus

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rotavirus

dsRNA virus
-reoviridae family

five species - A, B, C, D, E

A - most common - >90% of infections

fecal-oral transmission
-often stomach flu

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rotavirus infection

easily managed
-but causes lots of death worldwide - developing countries

oral rehydration therapy and vaccines

malabsorption
-toxic protein NSP4

may also see lactose intolerance - for weeks

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rotarix

vaccine for rotavirus

attenuated live virus

oral admin

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ingestion of preformed toxins

rapid onset

staph food poisoning

vibrio

c perfringens

c botulinum

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infection by toxigenic organisms

incubation - then diarrhea

travelers diarrhea
e coli
v cholerae
campylobacter

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infection by enteroinvasive organisms

invade destroy mucosa

shigella
salmonella
campylobacter
enteroinvasive e coli

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E. coli

gram negative bacilli
-colonize GI tract

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ETEC

enterotoxic e coli

travelers diarrhea
food or water spread

heat labile toxin and heat stable toxin

induce chloride and water secretion

secretory diarrhea, dehydration

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EHEC

E. coli 0157:H7

undercooked beef

shiga-like toxins

bloody diarrhea and HUS

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EIEC

food, water, person to person

no toxins
-invade epithelial cells

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EAEC

enteroaggregative e coli

adhere to epithelial

cause of diarrhea

adhere with adherence fimbrae

damage due to adherence

nonblood diarrhea - prolonged in AIDS patients

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campylobacter

water or bloody diarrhea

arthritis

guillan barre syndrome

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salmonella

gram negative bacilli

typhi - typhoid fever
nontyphi - enteritidis

raw or undercooked meat

few organisms required for infection

bacteria grown in phagosomes

Th17 limits to colon

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diagnosis of salmonella

stool culture

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typhoid fever

salmonella typhi

travel to india, mexico, phillipines, etc.

enlarged peyers patches in terminal ileum

oval ulcers - oriented along axis of ileum - may perforate**

liver - typhoid nodules

abdomen pain, bloating, nausea, vomiting, bloody diarrhea - fever and flu-like sx

blood cultures positive - more than 90% during febrile phase

rose spots - chest and abdomen

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cholera

gram negative bacteria

contaminated drinking water

cholera toxin - causes disease
-five B subunits and single A subunit
-B goes retrograde transport to ER - A then reduced
-A released to cytosol
-interacts with ARF to activate and increase cAMP
-causes chloride release to lumen
-massive diarrhea

flagella for colonization

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rice water stool

cholera

with fishy odor

dehydration, hypotension, shock

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campylobacter jejuni

gram negative motile

most common enteric pathogen developed countries
-travelers diarrhea

improper cooked chickens

four virulence properties
-motility, adherence, toxin, invasion

flagella - motlie

see arthritis, erythema nodosum, guillan barre syndrome

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most common bacterial enteritis in the world

campylobacter

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shigella

gram negative bacilli
unencapsulated, nonmotile facultative anaerobes

watery diarrhea progres to bloody diarrhea - dysentery

resistant to acidic stomach

taken up by M cells

to left colon

diagnosis - stool culture

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reiter syndrome

complication of shigella

arthritis, urethritis, conjuntivitis

HLA-B27 positive men

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pseudomembranous colitis

antibiotic associated
-3rd gen cephalosporins

c. difficile overgrowth and toxin production - A and B toxins

in adults - acut ediarrhea

diagnosis - C. dif in stool

eruption reminiscent of volcano

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diagnosis of c dif infection

presence of toxin

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volcanic eruptions

c dif - pseudomembranous colitis

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whipple disease

relapsing multisystem illness of GI tract and distant sites

weight loss, diarrhea, polyarthritis

tropheryma whipplei

40-50yo, males

tx - antibiotics

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trophermya whipplei

whipple disease

gram positive actinomycete

foamy macrophages with argyrophilic rods in lymph nodes

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path of whipple disease

malabsorptive diarrhea - impaired lymph transport

organism clogs up nodes and lymph tracts

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distended foamy macrophages

whipple disease

PAS positive rod shaped bacilli

and NO acid-fast staining

t. whippelii

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diarrhea, weight loss, and malabsorption

triad of whipple disease

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cryptosporidium

contaminated drinking water

travelers diarrhea

terminal ileum and right colon

intracellular at brush border

H and E stain and Ag stain

appears to sit on top of epithelial apical membrane

diagnosis - oocysts in stool

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AIDS and diarrhea

50% patients

cryptosporidium
CMV
MAI

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pinworms

enterobius vermicularis
-live in intestinal lumen - rarely cause illness

eggs deposited at night at perirectal mucosa- irritation
-itchy

diagnosis - tape to anus

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ascaris

small intestine roundworm
-a. lumbricoides

compromised nutritional status

SOB, fever, abdomen pain, diarrhea, malnutrition, mental changes

eggs hatch in intestines - go to lungs - coughed up and swallowed

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amebiasis

entamoeba histolytica
-ingestion of mature cysts

trophozites invade intestinal mucosa

cecum and ascending colon

abdomen pain, diarrhea, weight loss

acute necrotizing colitis and megacolon possible

obligate fermenters of glucose

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most common parasite infection

giardia

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giardia

g. duodenalis and g. intestinalis

asymptomatic, acute diarrhea, or chronic GI disease

malabsorption, diarrhea, abdominal pain/discomfort

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giardia morph

flagellated protozoans

cause decreased expression of brush border enzymes

pear shape with two nulei and line down middle

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steatorrhea

bulky, frothy, greasy, yellow, gray stool - with malabsorption

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ADEK

fat soluble vits - with malabsorption

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most common causes of malabsorption

celiac
pancreatic insufficiency
crohn disease

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abetalipoproteinemia

only see transepithelial transport defect

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altered lymph transport

whipple disease

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celiac disease

inflammatory disease
-gluten ingestion

genetic predisposition, inciting agent exposure, T cell repsonse

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gliadin

disease producing component of gluten

induce IL-15 expression stimulates T8 Cells

enters and stimulates T4 cells - to create B cells - make Abs

path - is CD8 cells

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class II HLA DQ2 and DQ8

carried by those with celiac

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celiac clinical

steattorhea, weight loss, abdominal pain cramping bloating, mouth ulcers, lactose intolerance, IBS

increased risk of adenocarcinoma and lymphoma

malaborption vits A, D, E, K

anemia, fatigue, megaloblastic anemia, hyperparathyroid, osteopenia, osteoporosis

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celiac disease

adults 30-60yo and children

diarrhea with steatorrhea

dermatitis herpetiformis

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dermatitis herpetiformis

extremely itchy blisters extensor surfaces of body

IgA deposition at dermal/epidermal junction

with celiac disease**

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celiac tx

remove from diet

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diagnosis of celiac

1 clinical malabsorption
2 small bowel bx - gold standard
3 response to gluten free diet

also serologic testing and HLA testing
-if IgA deficient - sero tests won't work

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gold standard celiac diagnosis

small bowel biopsy
-distal duodenum/jejunum

-villous atrophy

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celiac sero tests

IgA tTG antibodies

also anti-endomysial antibodies - IgA EMA

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cracked mud mucosa

in celiac on endoscope