Infectious Diarrhea DSA Flashcards
Who is at high risk for infectious diarrhea?
travelers
immunodeficient
daycare people
institutionalized people
consumers of certain foods (wtf?)
What is the most important thing to look for on PE for infectious diarrhea?
signs of dehydration
mild: thirst, decreased fluid output
moderate: orthostatic BP, tenting, sunken eyes/fontanelle
severe: lethargy, hypotension, shock
Acute infectious diarrhea is transmitted how?
fecal oral
(mild and self limited)
when to work up infectious diarrhea?
profuse diarrhea with 6+ stools per day WITH dehydration
hypotension/tachycardia
fever
>48hrs without improvement
What is the cornerstone of diagnosis for infectious diarrhea?
microbiologic analysis of the stool
routine studies: salmonella, shigella, E. coli, campylobacter
takes 24-48hrs
What are some specific stool analyses?
special cultures for EHEC, Vibrio, and Yersina
PCR for C. diff
ova/parasites
protozoa antigens for giardia, crypto, E.histolytica
PCR antigen for rotovirus, norwalk
When to suspect food poisoning?
summer-time, several sick members from picnic/banquet/restaurant
routine testing not done
Common causes of food poisoning?
chicken (salmonella, campylobacter)
beef (EHEC)
fried rice (B. cereus)
potato salad (s. aureus)
lunch meats (listeria)
seafood (vibrio, norovirus)
What is the micro of S. Aureus?
Sx
risk factors?
g+ cocci, preformed enterotoxins
watery diarrhea, N/V, onset within 6 hrs, better in 24-48
eggs, cream pastries, potato salad, mayo
Micro of B. Cereus
Sx
risks
g+ rods, preformed enterotoxins
rapid onset vomiting, 6hrs of ingestion, watery diarrhea, better in 24-48 hrs
fried rice
Micro for C. perfringens?
sx
risks
g+ heat resistant spore forming rods with entertoxins
watery diarrhea, no vomiting
onset 6-18hrs, acid labile, better 24-48 hrs
beef, ham, poultry, legumes, gravy
Micro of shigella
sx
treat
risks
complications
g- rods, toxin mediated
bloody diarrhea, pus, fever, fecal leukocytes
difficult to differentiate from IBD
1-2wks long
bismuth, abx
lettuce raw veg.
reactive arthritis
Micro of salmonella
sx
dx
tx
risks
complications
gram -, infects peyers patches, non-typhoid in US
bloody diarrhea
stool culture
self limitied 5-10 days
eggs, poultry, reptiles, Sickle Cell
septic arthritis, abcess, osteomyelitis
micro for salmonella typhi
sx
dx
tx
gram-, anaerobic
typhoid fever, salmon/rose colored rash, pea soup poo, bradycardia
stool and blood cultures
fluoroquinolines
risks: travel, poor sanitation
micro of C. jejuni
sx
dx
tx
risks
complications
gram-, cruved, spiral rod
bloody diarrhea
fecal leukocytes
campy blood agar,
self limitied, 7 day illness
poultry
guillan barre
V. cholorae micro
sx
dx
risks
treatment
gram-, anarobic, curved with flagella, toxin
rice water diarrhea, dehydration
stool micropscopy, gram stain
waterborn illness, seafood
rehydrate, vaccinate
V. parahmolyticus micro
sx
dx
tx
risks
gram-, cytotoxin, bacilli
N/V, blood diarrhea
self-limited
seafood
Micro of V. vulnificus
Sx
risks
gram - bacilius
bullous skin lesions, cirrhosis, vomiting, diarrhea
coastal sea water, shellfish
A. hhydrophila micro
sx
tx
risks
gram-, non-spore forming rod, flagella
two types cholera like-watery and bloody
ampicllin
fresh water fish/shelflfish, wound in water, nec fasc., gastroenteritis if swallowing water while diving/swimming
Travellers diarrhea
recent travel
watery diarrhea
self limitied
often ETEC
Micro of ETEC
Sx
Dx
Tx
Risks
gram - rod,
watery diarrhea
fecal leukocyte neg, clinical diagnosis
abx treatment
food/water esp in kids and elderly
EHEC micro
sx
dx
tx
risks
complications
gram-, rod, shiga toxin
blood diarrhea, no fever
elevated leukocytes, shiga toxin
supportive, rehydration
undercooked burger
hus, more common in kids
EAEC is bloody or not bloody?
EPEC is blood or not bloody?
EIEC is blood or not bloody?
not bloody
both (infantile)
bloody
Y. enterocolitica micro
sx
dx
tx
risks
complications
gram - coccobacilli
bloody diarrhea, right sided abd pain,
fecal leukocytes +
supportive care
deranged iron metabolism
reactive arthritis, erythema nodosum
L. monocytogenes micro
sx
dx
tx
risks
complications
gram + rod
non bloody diarrhea
blood culture, no listeria in stool sample
ampicillin
pregnant woman issues with placenta, deli meats
meningoencephalitis and listeria placentitis
Rotavirus micro
sx
dx
tx
risks
DSRNA,
vomiting and watery diarrhea
viral culture or PCR, wagon wheel appearance
supportive care, vaccine
infants and children, esp in winter
adenovirus micro
dx
dx
tx
risks
dsDNA
fever, watery diarrhea and vomiting, eye issues
viral culture
supportive care
children
Norovirus micro
sx
dx
tx
risk
small, naked RNA virus
vomiting, watery diarrhea
viral cultures usually unrevealing, fecal leuk. -
supportive care
older children and adults, nursing homes, schools, cruises
CMV mircro
sx
dx
risks
dsDNA, linear
fever, bloody diarrhea
endoscopy with biopsy shows ulcerated lesions
AIDS pts CD<200
E. histolytica micro
sx
dx
tx
risks
complications
trophozite, most common cause of dysentery
bloody dairrhea, liver abscess
flask shaped ulcer, ova and parasite stool or stool antigen
crowded living, endemic areas, poor sanitation
metronidazole
toxic megacolon or pneumatosis coli
G. lamblia micro
sx
dx
tx
risks
4 flagella, 2 nuclei protozoan
watery persistent diarrhea
ova parasites, fecal leuk.-, stool antigen detection
supportive care or metronidazole
water, hiking campling, IgA def. more susceptible
C. parvum micro
sx
dx
tx
risks
4 motile sporozoites
watery diarrhea
stool ag detection or direct microscopy, modified acid fast staining, DFA
resistant to chlorine treatment
swimming pools
S. stercoralis micro
sx
dx
tx
risks
nemotode, enters through bare feet
of asymptomatic, abd, vomiting, rash
rhabditiform larvae in stool, eosinophils
anti-helmintic
C. cayetanensis micro
sx
dx
tx
risks
produce, water even treated with Cl or I
watery diarrhea can last up to 3wks
fecal leuk-, oocytes in stool
TMP-SMX,
C. belli micro
sx
dx
tx
risks
tropical and subtropical areas
acute, non bloody, watery diarrhea
may have eosinophilia, repeated stool examinations and concentration procedures are recomended
may be seen in duodenal biopsy
stained with modified acid fast
tx with bactrim DS
What is a complication of ascaris lumbricoides
bowel obstruction
What is a complication of D. latum fish tapeworm
?
vitamin B12 def.
What is the 2nd most common cause of esophageal varices in africa?
Schistosoma mansoni
causes bloody stools, bladder cancer, liver cysts
T. solium comes from what animal and can cause what severe problem?
pork, seizures
E. granulosus main carrier is what?
forms what where?
comes from dogs
forms cysts in liver or lungs “hydatid sand” on CT
What causes severe perianal itching?
E. vermicularis
What is general treatment and hydration rules for diarrhea due to ifnection?
hydration PO or IV to maintain electrolyte balance
antimolitility agents can be used IF patient has no fever and nonbloody stools (not in EHEC or c. diff)
Best prevention of infectious diarrhea?
washing hands with soaps and waters
alcohol based rubs are ineffective against norovirus and C. diff
PPx for travellers?
antibiotic prophylaxis for travelers is generally not recommended
occasionally, will give cipro, azith, or rifaximin
What is reactive arthritis?
arthritis
urethritis
conjunctivitis
(can come with salmonella, campylobacter, shigella, yersinia)
Pathogens that cayse watery stools typically affect which part of the bowel?
small bowel
can cause weight loss, dehydration and malabsorption
Pathogens that cause blood and or wbc in the stool are typically located where?
in the large bowel
Which types of immunosuppressed patients are at greater risk of developing diarrhea?
lymphoma, bone marrow transplant, hiv, IgA def., hemochromatosis, AIDS with CD4<200
What are opportiunistic infections in AIDS patients?
mycobacterium species, CMV, adenovirus, HSV, protozoa
