GI Infections Flashcards
Viral Gastroenteritis
US most cases viral, brief, self-limited; vaccine avail (roto)
Viral Gastroenteritis Signs/Sx
Diarrhea (w/N/V); absence of fever, severe abd pn, bloody stool
Viral Gastroenteritis Etiology
Diff causes (roto; noro - explosive sx; astro; adeno - illness first, then GI sx); fecal-oral route
Viral Gastroenteritis Diag workup
Stool cultures after sev days to R/O bact gastroenteritis (high costs)
Viral Gastroenteritis Management
Antiemetics, antipyretics, hydration; antidiarrheal (not for bact)
Viral Gastroenteritis Prog/Comp/Prevent
Hand washing
Typhoid Fever
Common in travel
Typhoid Fever Signs/Sx
Fever, malaise, arthralgia, myalgia, HA, delirium; GI symptoms delayed (abd pn and constipation > “pea soup” diarrhea)
Typhoid Fever Etiology
Caused by salmonella typhi and paratyphi; systemic infection following 1-2 weeks incubation
Typhoid Fever Diag workup
Bradycardia, HSM, LAD, macular rash (rose spots); stool cx
Typhoid Fever Management
Quinolones, 3rd gen cephalosporins; corticosteroids; cholecystectomy considered if not cleared
Typhoid Fever Prog/Comp/Prevent
Recurrent bacteremia is common
Cholera Signs/Sx
“Rice water” stools; rapid/severe dehydration (mortality high)
Cholera Etiology
Contam seafood (shellfish); water, food contam w/human feces
Cholera Diag workup
Look for vibrio cholerae w/dark field microscopy w/wet mount
Cholera Management
Rehydration salts; abx can decrease duration: tetra/doxycycline
Cholera Prog/Comp/Prevent
Death from profound hypovolemia; vaccine available but not cost effective; 20-50% fatality if untreated
Giardiasis
Camping, wells (for drinking water); most common parasite in US
Giardiasis Signs/Sx
Asxatic, steatorrhea, bloating, flatus, fever uncommon, sulf belch
Giardiasis Etiology
Drinking water, contact cysts, attach to duodenum and jejunum
Giardiasis Diag workup
O&P, antigen testing
Giardiasis Management
Metronidazole (don’t take with EtOH)
Giardiasis Prog/Comp/Prevent
Causes lactose intolerance (avoid x 1 month); boil water while camping/iodine treatment for water
Shigella Signs/Sx
Fever, malaise, abd pn, watery/bloody diarrhea, resp sx common
Shigella Etiology
S sonnei or s dysenteriae; person-to-person; diarrhea may decrease and become bloody with mucus/pus
Shigella Diag workup
Stool culture
Shigella Management
Self-limiting; hydration and do not give anti-motility agents; high risk: Cipro
Shigella Prog/Comp/Prevent
Toxic megacolon, HUS, reactive arthritis (abx inc risk)
Salmonella
Cause gastroenteritis to typhoid fever
Salmonella Signs/Sx
N/V followed by inflammatory/bloody diarrhea, cramps; fever, RLQ tender
Salmonella Etiology
Summer or fall; undercooked/raw poultry, pets, person-person
Salmonella Diag workup
Test for S typhi in blood, bone marrow, rose spots, stool
Salmonella Management
Fluids, rest; avoid anti-motility agents; old/young/immunocompromised: abx
Salmonella Prog/Comp/Prevent
5-10% develop bacteremia, leads to: meningitis, pulm infs, osteomyelitis, reactive arthritis
Amebiasis
Entamoeba histolytica, most common parasite worldwide
Amebiasis Signs/Sx
Bloody diarrhea, abn pn, tenesmus (90% asxmatic)
Amebiasis Etiology
Transmission occurs thru ingestion of cysts from fecally contam food/water; can be person-to-person; flies/arthropods as vectors
Amebiasis Diag workup
Stool sample (3 samples because not sensitive); stool antigen test avail and more sensitive; exam of fresh ucer
Amebiasis Management
Metronidazole
Amebiasis Prog/Comp/Prevent
Can cause abscess (sp liver) -> tissue destruction; safe water supplies
C diff
Causes: abx-assoc colitis
C diff Signs/Sx
Watery diarrhea, abd pn/tenderness; (severe) loss of appetite, fever, blood in stool, weight loss
C diff Etiology
Gen iatrogenic (abx use - quinolone, clinda, PCN, cephs); fecal-oral route; disruption of normal intestinal flora
C diff Diag workup
Enzyme immunoassay available; colonoscopy
C diff Management
Vancomycin or flagyl (metronidazole)
C diff Prog/Comp/Prevent
Relapse common (add probiotic in tx); sx flare up in IBD
Campylobacter
2nd most common foodborne illness in US
Campylobacter Signs/Sx
Fevers, myalgias, malaise, abd pn, HA x up to 1 week
Campylobacter Etiology
Diarrhea begins later (profuse watery - bloody)
Campylobacter Diag workup
Stool culture
Campylobacter Management
Risk categories: <3 days erythromycin or quinolones (later)
Campylobacter Prog/Comp/Prevent
Hemolytic uremic syndrome, reactive arthritis, Guillain-Barre syndrome; thoroughly cook chicken
Bacillus cereus
Foodborne illness
Bacillus cereus Signs/Sx
N/V/D
Bacillus cereus Etiology
Toxins produced by Bacillus cereus causing sx
Bacillus cereus Diag workup
Culture from implicated food
Bacillus cereus Management
Self-limiting; symptomatic tx
Bacillus cereus Prog/Comp/Prevent
Avoid undercooked foods; prognosis good
E coli (Enterohemorrhagic -EHEC)
Many types
EHEC Signs/Sx
Abd pn, myalgia, HA, N/V, no fever, grossly bloody diarrhea (event)
EHEC Etiology
E. coli O157:H7 (an EHEC): produces Shiga toxin; incubation of 3-5 days
EHEC Diag workup
Does not show up on normal stool culture (let lab know)
EHEC Management
AVOID abx; avoid anti-motility/narcotics; replace water/electrolytes
EHEC Prog/Comp/Prevent
Caused by undercooked meat, unpasteurized milk (cattle feces); HUS, EHEC can appear like ischemic colitis (esp in elderly)
E coli (Enteroinvasive - EIEC)
Enteroinvasive E coli
EIEC Signs/Sx
Profuse diarrhea, vomiting, malaise, abd cramps, high fever/chills
EIEC Etiology
Occurs within 12-72 hours of eating contam food
EIEC Diag workup
Culture from infected food, but not usually needed
EIEC Management
Usually self-limiting
EIEC Prog/Comp/Prevent
Avoid undercooked food
E coli (Enterotoxigenic - ETEC)
“Traveler’s diarrhea”
ETEC Signs/Sx
Watery diarrhea, bloating, fatigue, cramps, fever uncommon
ETEC Etiology
Affects 40-60% of travelers to high-risk areas; bact 80-90%
ETEC Diag workup
Hx: where traveled
ETEC Management
Usually self-limiting; abx prophylaxis not rec; cipro or bismuth, rehyd
ETEC Prog/Comp/Prevent
Avoid undercooked foods, local water (ice), unpasteurized drinks
