H. pylori and diarrhea intro Flashcards
H. pylori causes..
gastric carcinoma (80%) esophageal SqCC non-NSAID type B gastric/duod ulcers PUD gastritis stuff/polyps a fib
genetic polymorphisms assoc. with gastric ca
IL-1B, IL-1B receptor, TNF-a, IL-10
H. pylori
G- curved rod, microaerophilic, oxidase positive, acid-tolerant, facultative IC organism
>50% cagA and vacA positive
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
H. pylori: vacA
cytotoxin, req. for ulcer formation, dysfunc. autophagy: hinders fusion of autophago with lysosome–>accel. H. pylori replication
H. pylori: LPS
affects production of acid and secretion of pepsinogen
H. pylori: Urease
essential for virulence and survival, cleaves urea–>ammonia and CO2, raises pH of v. acidic stomach, more livable
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
about ?? of world’s pop infected with H. pylori
affects who
15-20% will develop
50%
low SES
PUD, gastric ca
H. pylori transmission, etc
fecal-oral, gastric-oral, oral-oral intrafam spread, humans main reservoir inc. with age, not gender related no seasonality
H. pylori risk factors
crowding being a gastroent. fam contact certain MHC-II genotype *HLA-DR* haplotype via cross-reaction, molecular mimicry
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
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)
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
other H. pylori + assoc.
vascular disease (w. CagA+) idiopathic parkinsonism coronary instability (CagA+) dopa dysfunc, dec. PUFAs, inflamm, homocysteine alterations-->dev. of shizo
H. pylori - assoc.
childhood asthma
MS risk and severity in women
H. pylori assoc. dopa dysfunc, dec. PUFAs, inflamm, homocysteine alterations may play a role in dev. of
schizophrenia
H. pylori dir/indirectly raises ??? levels (think obesity) as it regulates ???
also cause ???
HbA1c
leptin/ghrelin
gastric inflammation–>metabolic syndrome
H. pylori is invasively dx by..
endoscopic biopsy: histo studies, brush biopsy
Cx (80% sn)
CLO test for urease
H. pylori is non-invasively dx by..
breath test w. 13C urea, meas. 13CO2 (esp kiddos
ddx H. pylori
steroids, NSAIDS, etOH
NSAIDS but NOT ASA inc. risk PU bleed if H. pylori present
H. pylori tx
triple threat: PPI, amoxicillin, clarithromycin
confirmed efficacy if dec. H. pylori IgG 1-3 mos post-tx
H. pylori ppx
soap and H2O, not etOH hand san
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
dx
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
