H. pylori and diarrhea intro Flashcards by Elizabeth DeGroot

H. pylori causes..

gastric carcinoma (80%)
esophageal SqCC
non-NSAID type B gastric/duod ulcers
PUD
gastritis stuff/polyps
a fib

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genetic polymorphisms assoc. with gastric ca

IL-1B, IL-1B receptor, TNF-a, IL-10

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H. pylori

G- curved rod, microaerophilic, oxidase positive, acid-tolerant, facultative IC organism
>50% cagA and vacA positive

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H. pylori: cagA

cytotoxin-assoc. gene A
most imp. virulence factor, inc. risk of gastric cancer with chronic gastritis
effector protein: inj. directly into host cell (type 4 secretion)–>invades stem-like cells–>translocates into gastric epi cells–>rearrrang. host cytoskel and alters cell signaling, perturbs cell cycle control
induce expression of a DNA-editing enzyme–>mutations in p53

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H. pylori: vacA

cytotoxin, req. for ulcer formation, dysfunc. autophagy: hinders fusion of autophago with lysosome–>accel. H. pylori replication

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H. pylori: LPS

affects production of acid and secretion of pepsinogen

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H. pylori: Urease

essential for virulence and survival, cleaves urea–>ammonia and CO2, raises pH of v. acidic stomach, more livable

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enterohepatic Helicobacter spp. (EHS)

extragastric: hepatobiliary tract
H. hepaticus, H. bilis, H rapipini, H. ganmani, H. pullorum
chr. pancreatitis, pancr. ca, and IBD: + for EHS

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about ?? of world’s pop infected with H. pylori
affects who
15-20% will develop

50%
low SES
PUD, gastric ca

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H. pylori transmission, etc

fecal-oral, gastric-oral, oral-oral
intrafam spread, humans main reservoir
inc. with age, 
not gender related
no seasonality

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H. pylori risk factors

crowding
being a gastroent.
fam contact
certain MHC-II genotype 
*HLA-DR* haplotype via cross-reaction, molecular mimicry

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H. pylori s/s

gradual onset (wks-mos) burning (epigastric) ulcer when empty
sometimes: N/V/anorexia, bloody or tar-like stools, vomiting bood, hemoptysis

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H. pylori can also cause ??? anemia

not assoc. with ??

sideropenic (refractory) iron-deficiency anemia and anemia of pregnancy
vomiting up or shitting out blood (absence of active GI bleed)
dec. response to iron therapy (eradicate pylori to inc. response)

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relationship btw ??? and H. pylori (hint: blood)
mechanism?
tx?

idiopathic thrombocytopenic purpura (ITP)
molecular mimicry btw antiplatelet Abs and CagA
eradicate w/ abx to show platelet response
also similar link to: lichen planes and rosacea

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other H. pylori + assoc.

vascular disease (w. CagA+)
idiopathic parkinsonism
coronary instability (CagA+)
dopa dysfunc, dec. PUFAs, inflamm, homocysteine alterations-->dev. of shizo

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H. pylori - assoc.

childhood asthma

MS risk and severity in women

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H. pylori assoc. dopa dysfunc, dec. PUFAs, inflamm, homocysteine alterations may play a role in dev. of

schizophrenia

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H. pylori dir/indirectly raises ??? levels (think obesity) as it regulates ???
also cause ???

HbA1c
leptin/ghrelin
gastric inflammation–>metabolic syndrome

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H. pylori is invasively dx by..

endoscopic biopsy: histo studies, brush biopsy
Cx (80% sn)
CLO test for urease

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H. pylori is non-invasively dx by..

breath test w. 13C urea, meas. 13CO2 (esp kiddos

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ddx H. pylori

steroids, NSAIDS, etOH

NSAIDS but NOT ASA inc. risk PU bleed if H. pylori present

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H. pylori tx

triple threat: PPI, amoxicillin, clarithromycin

confirmed efficacy if dec. H. pylori IgG 1-3 mos post-tx

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H. pylori ppx

soap and H2O, not etOH hand san

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acute diarrhea
persistent if ???
chronic if ??

3+ stools/day of dec. form 2 wks
>1 mo
*most is self-limiting

dysentery

intestinal inflammation (esp. colon) + pain, tenesmus, stools w. mucus and blood

2 main mechs of diarrhea: intoxication and infection

intox: staph; pre-formed in food infec: cholera, ETEC, Shigella, etc

other mechs of diarrhea

``` hormone-sec. tumor nutri. malabsorption food allergy DM, hemochromatosis, SLE, SCD, hemophilia stress ```

low infective dose exs

Shigella, Entamoeba, Giardia (Mt. range) | easily spreads from direct contact

high infective does ex

Salmonella (Mt. peak), | everyone gets sick @ same time

immunity in the intestinal epithelium: ??? can present Ag, express sec. component, and transport ?? ?? act as cytotoxic cells

enterocytes IgA intraepithelial lymphocytes

bacterial flora that cause inflammation and are associated with periodontal dis. and IBD the alteration triggers ?? causing inflamm. and inc. IBC

prevotellaceae bacterioidetes TM7 phylum members CCL5 secretion

host protein ??? is assoc with healthy gut microbiota | if deficient, showed....

NLRP6 | dec. levels IL-18 (pro-inflamm. cytokine) and alt. fecal microbiota

higher use of abx usage in childhood linked to

allergic eczema, asthma | atopy, Crohn's disease, IBD, DM obesity, autism

if vomiting predom. symp

food-borne, viral (less common symp. than diarrhea)

if large amount mucus in stools

invasive bac diarrhea

blood in stool

inflammatory, cytotoxin, invasive (dysentery)

watery diarrhea

small bowel

fever**

invasive pathogen

HUS

STEC, EHEC

prodrome

campylobacteriosis

microscopic exam #/types of WBCs-methylene blue leuko-test for leukocyte esterase tests for fecal lactoferrin

WBCs present in | absent in

invasive bac. inf. and abx rel. diarrhea (C. diff) | viral, parasitic, enterotoxigenic bac (cholera, ETEC), FBIs

routine stool Cx orgs

Salmonella, Shigella, Campylobacter, and enterohemorrhagic (sorbitol-negative) E. coli, Aeromonas/Plesiomonas

special stool Cx orgs

Yersinia enterocolitica Vibrio cholerae Non-cholera vibrios Clostridium difficile Others (food borne)

tests for O and P

Direct wet mount Concentration procedure Staining

parasite immunoassay for

Giardia, Entamoeba, Cryptosporidium

modified AF stain (parasites)

Cryptosporidium, Isospora, Cyclospora

Trichome stain

Microsporidia

PCR for

bac: Campylobacter, Clostridium difficile toxin A/B, Escherichia coli O157, enterotoxigenic E coli (ETEC) LT/ST, Salmonella, Shigella, and Shiga-like toxin producing E coli (STEC) stx 1/stx 2 viruses: (norovirus and rotavirus A) parasites: (Cryptosporidium and Giardia).

immunoassays

C. difficile toxins A and B Shiga (Vero) toxin Rotavirus

electron microscopy for

viruses

light microscopy/visual

``` acterial motility (vibrio, Campylobacter) Flecks of mucus (rice water stools- V. cholerae) Occult blood or frank dysentery ```

other assays

Fecal fat (steatorrhea) Fecal leukocytes Leukocyte esterase Fecal lactoferrin

blood tests for all pts (watery diarrhea)

Complete blood cell count with differential Electrolyte levels Albumin level Prothrombin time Folate concentration Iron studies Vitamin B12 concentration Thyroid-stimulating hormone level Erythrocyte sedimentation rate or C-reactive protein level

blood tests for select pts (watery diarrhea)

Celiac serologies Thyroid-stimulating hormone level Amebic serology D-xylose (after 25-g load, urinary level also acceptable) HIV (ELISA)

fecal tests for all pts (watery diarrhea)

Culture and sensitivity Ova and parasites (3 specimens) Giardia antigen ELISA Clostridium difficile toxin assay Fecal occult blood Fecal fat (qualitative) Fecal leukocytes

fecal tests for select pts (watery diarrhea)

α1-antitrypsin clearance ELISA

diarrhea general tx

fluid/e-lytes BRAT for kiddos restr. use abx (Rifaximin for trav. diarrhea ppx) probiotics (Lactobacillus rhamnus and L. reuteri)-kiddos and IBS adults