Clin - Acute Infectious Diarrhea Flashcards
cornerstone of diagnosis in acute infectious diarrhea
microbiologic analysis of the stool
what bacteria are tested for in a routine stool culture
- salmonella
- shigella
- E. coli
- campylobacter
if stool studies are unrevealing in acute infectious diarrhea, what diagnostic test should you do
endoscopy
- flexible sigmoidoscopy w/ biopsies
- upper endoscopy w/ duodenal aspirates and biopsies
what do abd x-rays check for in acute infectious diarrhea
detect free intraperitoneal air
- assess for ileus or toxic megacolon
what do abd CTs check for in acute infectious diarrhea
colitis
bacteria found in uncooked foods, lunch meat, or soft cheeses
listeria
pathogens found in raw seafood
- vibrio species
- salmonella
- acute hepatitis A
- norwalk virus
- campylobacter
gram stain of s. aureus
gram positive cocci in clusters (like grapes)
sx of s. aureus ingestion
1) watery diarrhea
2) N/V
(rapid onset within 6 hrs of ingestion)
bacteria in cream pastries, potato salad, mayo
s. aureus
gram stain of b. cereus
gram positive rods
sx of bacillus cereus ingestion
1) watery diarrhea
2) vomiting (main sx)
(rapid onset within 6 hours of ingestion)
bacteria in fried rice
b. cereus
gram stain clostridium perfringens
gram positive spore-forming rod
sx of clostridium perfringens ingestion
1) watery diarrhea
2) crampy abd pain
(rapid onset within 8-16 hours of ingestion)
risk factors for clostridium perfringens ingestion
- beef, ham, poultry, legumes, gravy
- inadequately cooked food (it is HEAT RESISTANT)
gram stain shigella
gram negative rods
sx of shigella
1) watery diarrhea that becomes bloody
2) abd cramps
3) fever for 3-4 days
diagnostic tests for shigella
1) fecal leukocytes
2) stool culture
where is shigella found in food
potato or egg salad, LETTUCE, raw vegetables
tx for shigella
bismuth, ampicillin, fluoroquinolone
complications of shigella
reactive arthritis and HUS
gram stain salmonella typhimurium
gram negative, non-lactose fermenting, motile, rod shaped
are antibiotics indicated in salmonella typhimurium
nope
typhimurium is the non-typhoid salmonella
what patients are at increased risk for salmonella typhimurium
1) sickle cell patients
2) leukemia pts
3) HIV
complications of salmonella typhimurium
1) reactive arthritis
2) endocarditis
3) septic arthritis
4) abscesses
5) osteomyelitis
what food and animal exposures increases risk for salmonella typhimurium
- eggs, poultry
- reptiles (turtles)
gram stain salmonella typhi
gram negative rod, anaerobic
sx salmonella typhi
typhoid fever 7-14 days after ingestion
- 2 symptomatic phases separated by asymptomatic phase
1) sustained 103-104 fever
2) weakness, HA, anorexia, RUQ pain, maculopapular rash, pea-soup diarrhea –> bloody diarrhea
3) encephalopathy, splenomegaly, conjuctivitis
diagnostic tests for salmonella typhi
1) stool culture
2) blood culture
gram stain c. jejuni
gram negative curved/spiral-shaped rod
spiral shaped or comma shaped
associated with guillian-barre syndrome
campylobacter jejuni
gram stain v. cholerae
gram negative bacilli, anaerobic, curved/comma shaped, with flagellum
tx vibrio cholerae
rehydration/electrolyte replacement
gram stain vibrio parahemolyticus
gram negative bacilli w/ cytotoxin production
sx vibrio parahemolyticus
- N/V/abd cramps
- water –> bloody diarrhea
(lasts 2-5 days)
what foods can harbor vibrio parahemolyticus
seafood
gram stain vibrio vulnificus
gram negative bacillus
sx vibrio vulnificus
- vomiting/diarrhea/abd pain
- pt with open wound in the water
risk factors for vibrio vulnificus
coastal salt water, raw shellfish
gram stain aeromonas hydrophila
gram negative bacillus, non-spore forming, facultatively anaerobic bacteria, motile w/ flagellum
sx aeromonas hydrophila
two types:
1) cholera like (non blood diarrhea, water rice water stools)
2) bloody mucoid stools
tx aeromonas hydrophila
ampicillin
risk factors for aeromonas hydrophila
1) fresh water environment
2) eating fish or shellfish
3) open wounds in water (foot and ankle most common)
scuba diver that swallowed small amounts of fresh water and then developed gastroenteritis
aeromonas hydrophila
visitors to russia who develop diarrhea
giardia
tx ETEC
- antibiotics
- bismuth
diagnostic results in EHEC
1) peripheral leukocytes, anemia, thrombocytopenia
2) fecal leukocytes
3) fecal lactoferrin
4) shiga like toxin in stool culture
tx EHEC
1) supportive
2) rehydration
3) antibiotics only in severe cases (antibiotics can increase risk of HUS)
complications of EHEC
HUS
gram stain yersinia enterocolitica
gram negative coccobacili
abd cramping and pharyngitis
yersinia enterocolitica
what dz can yersinia enterocolitica mimic
appendicitis
what patients have higher risk for yersinia enterocolitica
those with derangements in iron metabolism
- iron overload syndromes
- cirrhosis
- hemochromatosis
- aplastic anemia
- thalassemia
gram stain listeria monocytogenes
gram positive rod
sx listeria monocytogenes
1) fever
2) non bloody diarrhea
3) headache, N/V
risk factors for listeria monocytogenes
- pregnant women
- extremes of age
- immunocompromised
- hemochromatosis
gram stain tropheryma whipplei
gram positive bacillus, not acid fast
diagnostic test for tropheryma whipplei
EGD with biopsy and periodic acid schiff (PAS)
sx tropheryma whipplei
1) fever
2) arthralgias
3) weight loss
4) malabsorption
5) chronic diarrhea
tx for tropheryma whipplei
antibiotics w/ drugs that cross the BBB
prognosis of tropheryma whipplei
if untreated, dz is fatal
gram stain c. difficile
anaerobic gram positive spore forming bacilli
diagnostic test for c. difficile
stool assay - PCR for toxin (A and B)
complications of c. diff
toxic megacolon
most common cause of acute diarrhea in infants (children <2)
rotavirus
virology of rotavirus
dsRNA
sx rotavirus
vomiting and watery diarrhea
“wagon-wheel” appearance on electron microscopy
rotavirus
virology adenovirus
dsDNA
sx adnovirus
- watery diarrhea and vomiting
- conjuctivitis
- pharyngitis
virology norovirus
small non-enveloped RNA virus
virology CMV
herpesvirus family: dsDNA (linear)
sx cytomegalovirus
fever, abd pain, bloody diarrhea
most common cause of dysentery in the world
entamoeba histolytica
parasitology of entamoeba histolytica
trophozoite
“flask-shaped” ulcer on histology
entamoeba histolytica
risk factors for entamoeba histolytica
1) mental health institutions
2) poor sanitation
3) contaminated food/water
4) endemic areas
complications of entamoeba histolytica
1) toxic megacolon
2) pneumatosis coli
parasitology of giardia lamblia
pear-shaped, 4 flagella, 2 nuclei protozoan (trophozoite)
risk factors giardia lamblia
1) water - hiking/camping
2) beavers, cattle, dogs, rodents, big horn sheep
3) daycare
4) contaminated water in russia
5) IgA deficiency pts
parasitology of cryptosporidium parvum
oocyst with 4 motile sporozoites
risk factors cryptosporidium parvum
1) swimming pools
2) daycare
parasitology strongyloides stercoralis
nematode (roundworm)
- enters through bare feet
risk factors strongyloides stercoralis
pts with HTLV-1
sx cyclospora cayetanensis
1) watery diarrhea
2) malaise, anorexia, nausea, low grade fever
risk factors cyclospora cayetanensis
1) lettuce, fresh basil, imported raspberries
2) tx of water or food w/ chlorine or iodine is unlikely to kill cyclospora cayetanensis
3) endemic areas
sx cytoisospora belli
1) non-bloody water diarrhea
2) crampy abd pain
risk factors for cytoisospora belli
tropical and subtropical areas
- spread by ingesting contaminated food or water
what parasite can cause B12 deficiency
diphyllobothrium latum
sx and transmission of schistosoma mansoni
1) 2nd most common cause of esophageal varices in africa
2) contaminated freshwater snails
sx schistosoma mansoni
blood stools, bladder CA, liver cysts
compare sx b/w taenia solium and taenia saginata
solium: mostly asymptomatic, but rarely cause seizures and muscle or eye dz
saginata: mostly asymptomatic
transmission and sx of echinococcus granulosus
- sheep, dogs, poor sanitation
- cysts in liver or lungs
in what patients should you prescribe anti-motility agnets
those without fever and non-blood stools
NOT in c. diff or EHEC
nutrition recommendations for infectious diarrhea
1) BRAT diet (bananas, rice, applesauce, toast)
2) easily digestible foods (potatoes, crackers, yogurt, soup)
3) rice water
alcohol gels for hand sanitation are ineffective against what pathogens
C. diff and norovirus
what pathogens cause reactive arthritis (Reiter’s syndrome) with arthritis, urethritis, and conjuctivitis
- salmonella
- campylobacter
- shigella
- yersinia
compare sx b/w pathogens infecting the small bowel and large bowel
small bowel: large volume, watery stools, and cramps, weight loss, dehydration/malabsorption, no WBCs
large bowel: frequent small volume stools, may have: fever, blood or WBCs in stool, fecal leukocytes
pts with hemochromatosis are at risk for what pathogens
vibrio species, listeria, yersinia
