HRR: clinical GI infections Flashcards
What is the timing for diarrhea to be considered chronic?
2 weeks
What is dysentery?
Mucus, pus, blood in the stool
What would cause a short incubation period?
Less than 2 hours would be chemical agents, 2-7 hours would be due to pre-formed toxins
Describe staph aureus as a cause of food poisoning.
It has a heat stable toxin; cooking food again would not kill the toxin. incubation around 1-6 hours
Describe presentation of staph aureus food poisoning.
Not usually diarrhea or fever, definitely vomiting. Vomiting occurs soon after eating
How do we diagnose staph aureus food poisoning?
Clinically
Describe bacillus cereus as a cause of food poisoning.
Can either be via preformed toxin or toxin production after ingestion. incubation 1-6 or 6-24 hours
Bacillus cereus is classically associated with…
Rice
Describe clostridium perfringens as a cause of food poisoning.
Spores germinate and make toxin; 8–24-hour incubation
Describe the common symptom in clostridium perfringens food poisoning.
Severe abdominal cramping and diarrhea
Are GE syndromes from pre-formed toxin fatal?
Not usually
How do we manage gastroenteritis?
Usually just with rehydration; if there is dysentery or fever get a blood culture and stool study
Describe campylobacter as a cause of food poisoning.
Long incubation period of 2-5 days, commonly causes dysentery, often associated with poultry, and does not tolerate drying/freezing well
What is a potential complication of campylobacter?
Guillain-barre
Describe salmonella typhi.
Person-to-person cause of typhoid fever. Incubation period is 5-21 days, transient diarrhea, fever that will not shake in the 2nd or 3rd week
Describe non-typhoidal salmonellosis (salmonella typhimurium).
12–72-hour incubation period with fever, cramping, diarrhea and often linked to eggs/chickens
What is unique about non-typhoidal salmonellosis (salmonella typhimurium)?
It is hardy; lots of foods can become contaminated (potato chips, peanut butter, etc)
How do we treat non-typhoidal salmonellosis?
Antibiotics if it is severe, but otherwise just kinda wait it out because resistance is becoming common
Describe vibrio cholerae.
Acquired from environmental bacteria and is toxin mediated. Big cause of epidemic diarrhea and often associated with travel
Who is at risk for shigellosis?
Children (especially in daycare), travelers, HIV positive
What is the clinical syndrome of shigellosis?
Cramping and high fever with non-bloody diarrhea; usually gets better within a week
What is the infectious dose of shigella?
Tiny…only like 10
Do we give antibiotics to shigellosis?
No, unless it is a severe case
Describe STEC E. coli.
Shiga-toxin producing and often found in cattle. Has an incubation of 3-5 days and up to 10
What is the clinical illness of STEC?
A week’s worth of stomach cramping, vomiting, watery/bloody diarrhea, HUS
Do we treat E. coli?
No! this might increase risk of HUS
Describe ETEC E. coli.
Associated with water supply and travel. It has a 10–72-hour incubation period
What is the clinical syndrome of ETEC?
Water diarrhea, nausea, vomiting, fever
How do we treat ETEC?
We don’t
How do we prevent ETEC?
Avoid high risk food, prophylactic bismuth QID if needed
Describe yersinia enterocolitica.
1–10-day incubation period associated with pork and unpasteurized milk
What is the clinical syndrome of yersinia enterocolitica?
Pseudo appendicitis (severe pain) and non-bloody diarrhea
Describe giardia duodenalis.
Longer incubation period of 3-25 days associated with camping, well water, travel, child care
What is the clinical syndrome of giardia duodenalis?
Explosive diarrhea, cramps, nausea, often relapse
Describe cryptosporidium.
Incubation period of 2-10 days associated with water exposure and immunosuppression
What is the clinical syndrome of cryptosporidium?
Nausea, vomiting, fever, weight loss, sporadic symptoms over a month-long period
How do we diagnose cryptosporidium?
Acid fast stain or PCR
Describe cyclospora.
Incubation period of 1-11 days and associated with a bunch of foods like raspberries, basil, snow peas, etc. cannot be passed directly fecal-oral
What is the clinical syndrome of cyclospora?
Watery diarrhea for weeks/months, myalgia, fatigue
How do we diagnose cyclospora?
PCR
Describe c. difficile.
Usually acquired in hospital settings, and many people are asymptomatic carriers
Describe clinical syndrome of c. difficile.
Profuse and watery diarrhea, pseudomembrane colitis, possible relapse
How do we treat c. difficile?
Vancomycin
What do we test for if a patient is febrile or has blood in their stool?
Bacterial causes
What do we test for if symptoms are lasting longer than 7-14 days?
Parasites
What are the common features of diarrheal viruses?
Brief incubation, fecal-oral spread, vomiting
Describe norovirus features.
24–48-hour incubation period, with recovery in 48-72 hours. Super contagious and low infective dose
How long does viral shedding occur in norovirus?
2-4 weeks after symptom resolution
What is the clinical syndrome of norovirus?
Emesis, diarrhea, low-grade fever
How long does immunity to norovirus last?
Not long…maybe 5 months
What is the attack rate of norovirus?
Super high; lots of people will get it on exposure
How do secondary cases of norovirus occur?
Fomite transmission and person-to-person
What is the leading cause of acute gastroenteritis?
Norovirus; always suspect it
Describe sapovirus.
Non-enveloped virus found in humans, bats, pigs, etc. outbreaks are common in daycares and nurseries
Describe astrovirus.
Non-enveloped virus with person-to-person, fomite, fresh/marine water, and food supply transmissions
What is the clinical syndrome of astrovirus?
Mold diarrhea gastroenteritis in infants and young kids
What is unique about astrovirus?
Lifelong immunity!
Describe SARS-CoV2 as a GI syndrome.
May present with gastroenteritis, but isn’t super common
Describe infection of rotavirus.
Proteases in GI tract activate the virus upon ingestion via cleaving their outer capsid and generating ISVP
Is there a vaccine for rotavirus?
Yes; it used to cause a lot of hospitalization and death in kids
Describe the pathology of rotavirus.
Destroys villous structures of the duodenum and jejunum, decreasing absorptive ability and decreasing brush border enzyme production. This causes transient malabsorption
What viral protein in rotavirus may behave like an enterotoxin?
NSP4
What is the clinical syndrome of rotavirus?
Low grade fever, quick onset of vomiting, copious watery diarrhea
What is the major cause of morbidity in rotavirus?
Dehydration and hyponatremia
What is the incubation period of rotavirus?
1-3 days
Describe rotavirus in newborns.
They’re easily infected but usually have mild or no symptoms due to IgA in colostrum and inhibitory mucins in breast milk
What are the vaccines of rotavirus?
Rotate and Rotarix; both live, oral vaccines
How do we treat rotavirus?
Supportive care only
Describe adenovirus.
Non-enveloped DNA virus that causes a whole mess of symptoms
What is unique about adenovirus?
It causes latency via shedding
Which variants have a live oral vaccine for adenovirus?
4 and 7
How do we treat disseminated adenovirus?
-fovir drugs. This would NOT be used in healthy people
