Gastroenteritis Flashcards
Hx of gastroenteritis?
ask about ingestion of potentially contaminated food or water, travel, contact w/similarly ill person,medication use (abx use recently)
What is gastroenteritis?
inflammation of lining of stomach, SI & colon (from infxns most commonly)
typically self-limiting but can be serious in young, elderly, immunocompromised
Normal intestinal microflora? Where do you find the least amount of bac, why?
typically GI tract in habited by 500 different bac species
find least amount of bac in stomach & proximal small bowel b/c of acidity
Ssxs of gastroenteritis?
character & severity vary
sudden onset of NV anorexia, abd cramps & diarrhea mb malaise & myalgia
PE of gastroenteritis?
distended abd, enderness, borborygmi
Possible w/u of gastroenteritis?
stool testing, CBC, CMP
5 things that can cause gastroenteritis?
viruses, bacteria, parasites, fungal overgrowth & drug & chemical-related
Viral gastro makes up what percentage of infectious diarrhea in US? What is viral gastroenteritis? What does it cause?
30-4% of infectious diarrhea in US
viruses infect enterocytes in SI villi= transudate of fluid/salt into lumen
cause watery diarrhea stools rarely contain blood or mucus
What are the 5 types of viral gastro?
rotavirus, norovirus, astrovirus, enteric adenovrirus, CMV & enteroviruses in immunocompromised pts
Occurence of rotavirus? When does it peak? Ssxs?
most common cause of infectious diarrhea worldwide
33% of hospitalizations & 20% of deaths assoc w/infectious gastroenteritis
highly contagious (fecal-oral route)
prevalent throughout yr peaks in winter
ssxs: vomiting, fever >102, sxs can last 5-7 d
Who does norovirus affect & when? When can it become epidemic? contagious? Ssxs:?
older children & adults, year round
epidemic w/water & food-borne outbreaks
HIGHLY CONTAGIOUS
ssxs: acute onset vomiting, abd cramps, diarrhea, fever, HA, lasts 1-2 d
Who does astrovirus usu infect? when? route? Ssxs?
infants & young kids
winter months
fecal-oral route
ssxs: acute onset vomiting, abd cramps, diarrhea, fever HA, lasts 1-2 d
Who gets enteric adenovirus? when? route? ssxs?
kids <2 yo
year-round/summer
fecal-oral route
ssxs: diarrhea followed by mild vomiting, diarrhea that lasts 1-2 weeks
3 mechanisms utilized by bacteria to cause gastroenteritis?
exotoxins, enterotoxins, mucosal invasion
What is an exotoxin? what ssxs do they cause within how many hrs & sxs abate w/in how many hours? what is not in the stool?
toxin secreted by microorganism & released into enviro then ingested and causes N/V, watery diarrhea in 12 h of ingestion, sxs abate w/in 36 hrs, stools have no blood or WBCs
4 bugs that utilize exotoxins to cause bacterial gastroenteritis?
stapholococcus aureus, bacillus cereus, clostridium perfringens, clostridium botulinum
s. aureus gastroenteritis is usu caused by? common in what things? ssxs? course?
food poisoning w/toxin introduced by food-handlers
common foods involved: custard, milk products, potato salad, salad dressing, coleslaw, processed meat/fish at room temp
ssxs: sudden, abrupt, severe vomiting 2-6 hr post-ingestion, explosive diarrhea, abd cramps, rarely fever
course: 3-6 hrs, usu complete recovery
Where doe sone find bacillus cereus? fcommon things to find contaminated? ssxs? course?
spore-forming organism in soil, contamination of food before cooking which survive high heat
common foods: contaminated rice or meat
ssxs: 2 distinct syndromes: emesis (2-6 hrs after ingestion severe vomiting, abd pain w/ or w/o diarrhea, afebrile, no systemic sxs) & diarrhea (8-16 hrs, foul smelling, profuse w/nausea, abd pain, tenesmus)
course: resolves in 12-24 hrs
where do you find clostridium perfringens? most toxin synthesis occurs when? after ingestion of what things? ssxs? course?
spore-forming anaerobe in feces, soil, air, water
most toxin synthesized before ingestion, additional in GI
after ingesting contaminated beef, beef products, poultry, food inadequately pre-cooked & then reheated before served
ssxs: watery diarrhea, foul-smelling w/severe crampy abd pain, 8-16 hrs after ingestion
course: self-limited, resolves in 24-36 hrs
clostridium botulinum has hat 3 eotoxin types? causes waht serious complication? what 2 types are assoc w/improperly prepared home-canned non-acidic fruits & veggies? what type assocaited w/smoked freshwater fish? doing what can inactivate exotoxin?
A, B, E
responsible for 1/3 OF DEATHS from food borne dz
A & B associated w/improperly prepared home-canned non-acidic fruits & veggies
E smoked freshwater fish
boiling in water for 15 min can inactivate exotoxin
SSxs of clostridium botulinum?
incubation 4 hr- 8 d after ingestion
phase 1= vague, short period of fatigue, N/V, abd cramps, diarrhea
phase 2- visual, diplopia, decreased acuity, PERRLA, ptosis
phase 3- neuro, descending weakness or paralysis, dysarthria, dysphagia, weakness of trunk & extremities, sensorium unaffected normal or low temp, blood, urine, CSF normal
course of c. botulinum?
65% mortality 29 d following ingestion, w/tx <10% supportive to prevent respiratory impairment
ddx of c. botulinum gastroenteritis?
polio, encephalitis, M. gravis, curare, belladonna poisoning
What is an enterotoxin? specific for what? impair what? cause what?
cytotoxin produced by bac, specific for mucous membrane of intestine (in vivo)
toxins impair intestinal absorption, increases secretion of water & electrolytes causing watery diarrhea
What 3 bugs utilize enterotoxins to cause gastroenteritis?
cholera & non-cholera vibrio, enterotoxigenic escherichia coli & clostridium difficile
where are cholear & non-cholera vibrio endemic? dt what? incubation? in US dt what? ssxs?
endemic in Asia
any fecal contaminated water or food, in US from contaminated saltwater crabs & freshwater shrimp
incubation 1-3 d after ingestion
ssxs: sudden, painless, profuse, large volume, watery diarrhea, no blood or mucus, usu no fever, abd pain, vomiting, tenesmus, water & electrolyte loss leads to thirst, oliguria, muscle cramps, weakness, cold cyanotic skin, dehydration, hypotension, tachycardia
Course of cholera & non-cholera vibrio?
recover in 7-10 d if rehydration is adequate, fatal in over 50% of untreated severe cases
What does enterotoxigenic e.coli cause? route? incubation? ssxs?
diarrhea caused by tissue invasion or via its enterotoxin
fecal/oral route of contaminated water or food, traveler’s pathogen
incubation: 1-3 d
ssxs: profuse, watery diarrhea, 3-5 d
How does c diff cause gastroenteritis? ssxs?
overgrowth of intrinsic organisms (post abx) or infxn by external source (soil, water, household pets)
cytotoxin & enterotoxin cause pseudomembranous colitis
commonly nosocomial dz, in hospital stay or nursing home or iatrogenic dz after abx use
ssxs: watery diarrhea, cramping abd pain, N/V=RARE
what is a complication of c. diff? Describe the complication. PE, W/U, complication of it? what procedure is contraindicated?
TOXIC MEGACOLON
dilated colon w/fever, abd pain, tachycardia
PE: tender abd, absent bowel sounds
W/U: elevated WBC distended bowel on xray, colonoscopy is CONTRAINDICATED
risks of: perforation, sepsis, septic shock
other possible causes: UC, Crohn’s, entamoeba histolytica, yersinia infxn
What is mucosal invasion? what’s in the stool? difference b/w watery & bloody stool?
ingested organism causes microscopic ulceration, bleeding, exudates, secretion of electrolytes & water
stool has WBCs, RBCs, possibly gross blood, fever & prostration common, diarrhea may be watery or bloody
watery: >1 L/d, usu no fever, HA, myalgia, arthralgia
bloody: usu w/abd pain, tenesmus, N/V, fever, malaise
what 5 bugs use mucosal invasion to cause gastroenteritis?
salmonella, campylobacter jejuni & fetus, shigella, enterohemorrhagic e. coli & yersinis enterocolitica
Where do you find salmonella? sz of inoculum to make infection? ssxs? course?
ingestion of undercooked chicken or eggs, unpasteurized milk, contact w/reptiles
large inoculum to produce infxn
can cause exudative diarrhea or secretory
ssxs: watery diarrhea more common, bloody may occur, ha, malaise, N/v, abd pain 6-48 hrs after ingestion may have fever
course: usu self-limited to 7 d
What is the most common bac cause of bloody diarrhea in the US? from what? incubation? ssxs? course?
cmapylobacter jejuni & fetus
from contaminated pork, lamb, beef, milk products, water, infected pets
incubation= 7-10 d
ssxs: prodrome of HA, myalgia, malaise for 12-24 hrs then severe abd pain, high fever, profuse watery diarrhea, then bloody diarrhea
course: usu self-limited to 7-10 d
shigella occurs most commonly in what age? from what? contagious? ssxs?
children 6 mos-5 yrs
food, water, milk can be contaminated, person to person
HIGHLY CONTAGIOUS w/ very small incoculum
ssxs: incubation 1-3 d, starts as lower abd pain, diarrhea, fever in 50%, many have biphasic illness starting as fever, abd pain, diarrhea, then 3-5 d rectal burning, tenesmus, small vol blood diarrhea
course: variable- children resolves in 1-3 d, adults resolves in 1-7 d
What is enterohemorrhagic e. coli? produces what toxin? from where? ssxs? course? complications?
e. coli 0157:H7 produces shiga toxin
bovine reservoir, undercooked beef or unpasteurized milk, fecal-oral esp in daycare
ssxs: acute onset of severe abd cramps, watery diarrhea >16hr after ingestion, becomes bloody w/in 24 hrs!
course: 1-8 d if uncomplicated
complications: HUS: hemolytic anemia, thrombocytopenia, acute renal failure & TTP: HUS, fever, neurological deficits
Where do you get yersinia enterocolitica from? ssxs? what can it mimic?
undercooked pork, unpasteurized milk, contaminated water
ssxs: watery or bloody diarrhea & fever may mimic appendicitis if infxn in terminal ileum AKA acute ileitis
What is traveler’s diarrhea? what is the most common bac cause? most common viral cause? ssxs? onset? course?
gastroenteritis caused by contact w/organism endemic to locale visited usu contaminated water or food ingestion
enterotoxigenic e.coli is most common also norovirus
ssxs: N/V, borborygmi, abd pain/cramps, diarrhea
onset: 12-72 hrs after ingestion
course: usu self-limiting, fever & bloody diarrhea suggest more serious dz
3 types of parasitic infxns that can cause gastroenteritis?
giardia lamblia, cryptosporidium parvus, entamoeba histolytica
route for giardia? see in what pts especially? ssxs? course?
fecal-oral from contaminated water, person to person (daycare), traveler’s pathogen
esp in pts w/low IgA, hypochlorhydria, malnutrition, ingestion of cysts which break down releasing organism
ssxs: incubation 7 d, mb asx, mild, watery diarrhea, abd bloating, cramps, flatulence for 1-3 wk, stools bulky, foul smelling
course: mb self-limiting or infxn may persist & produce chronic or recurrent dz (celiac-like lesion causing lactose intolerance & malabsorption), fatigue, wt loss
What pts usu have cryptosporidium? via what? sxs? in 2 types of pts sxs will be what?
high rate of infxn in HIV, immune-compromised, daycare
via contaminated water, food, pets
ssxs: in non-immune compromised pt- profuse, watery diarrhea, anorexia, low-grade fever 5 d after ingestion
course: usu self-limited lasting ~2 wks
in immune compromised pt- mb chronic, watery diarrhea up to 17/d, leads to dehydration
Where do you get entamoeba histolytica from?
endemic, travel assoc, fecal-oral spread, in institutionalized pts HIV, AIDs, immune-compromised, cysts ingested, released leading to ulceration similar to IBD
ssxs: if mild= crampy, abd pain, intermittent diarrhea; if severe- bloody diarrhea, abd pain, tenesmus, fever, toxic megacolon
