Infections of the GI tract (Schoenwald) Flashcards
Is infectious diarrhea acute or chronic in onset?
Acute
How long does infectious diarrhea last for?
Lasts less than 2 weeks
What should be part of the history in patients with infectious diarrhea?
Travel history
What suggests a viral etiology of infectious diarrhea?
Community outbreaks in nursing homes, schools, cruise ships, or common food source
Watery, non-bloody diarrhea is characteristic of what kind of diarrhea?
Non-inflammatory
What are the sxs of non inflammatory diarrhea?
Cramping, bloating, nausea, vomiting- disrupts normal absorption in the small bowel
Will you see fecal leukocytes on a smear in non-inflammatory diarrhea?
No, no fecal leukocytes will appear on the smear because tissue invasion does not occur in non inflammatory diarrhea
What types of diarrhea accompanies fever and bloody diarrhea
Inflammatory
What type of diarrhea will you have colonic tissue damage from invasion of bacteria or toxin?
Inflammatory diarrhea, which is why it is bloody
What part of the colon is primarily involved in inflammatory diarrhea?
Lower colon
What sxs will you see in inflammatory diarrhea?
Lower quadrant cramping, urgency
Will there be fecal leukocytes present in inflammatory diarrhea?
Yes, because of invasion of mucosa
What should your differential include when diagnosing inflammatory diarrhea?
Ulcerative colitis
Diarrhea lasting longer than 14 days is most likely…
NOT due to an infectious agent (except c diff!)
What is the major difference between inflammatory and non inflammatory diarrhea?
Colonic tissue invasion by the organism and/ or toxin
Why is it important to classify the diarrhea as inflammatory vs non inflammatory?
Helps to differentiate when it is “okay” to use anti motility agents such as Imodium
What is Imodium?
Anti motility agent- helps with diarrhea
When should you absolutely not use antimotility agents?
In inflammatory diarrhea- this traps the organism in the colon, causing more damage, perpetuating the sxs, and prolonging the infection
What are some typical stool pathogens?
Salmonella Shigella Campylobacter Vibrio E Coli O157:H7 Clostridium difficile Norovius Enterovirus Parasites- giardia, amoeba, cryptosporidium
What organism should you suspect with previous antibiotic usage?
Cdiff
What causes non inflammatory diarrhea?
Enterotoxin production- Staph aureus B cereus Enterotoxigenic E. coli Vibrio cholerae
& Norovirus Rotavirus Giardia Cryptosporidium Listeria monocytogenes
What causes inflammatory diarrhea?
Cytotoxin production... Enterohemorrhagic E. coli 0157:h7 C diff Mucosal invasion... Campylobacter Shigella Salmonella
Cytomegalovirus
Entamoeba histolytica
What agents cause enterotoxin production in non-inflammatory diarrhea?
Staph aureus
Bacillus cereus
Enterotoxigenic E. coli
Vibrio cholerae
What agents cause cytotoxin production in inflammatory diarrhea?
Enterohemorrhagic E. coli 0157:H7
C diff
What agents cause mucosal invasion in inflammatory diarrhea?
Campylobacter
Shigella
Salmonella
What is the new name for C diff?
Clostridioides difficile
Previously clostridium difficile
What agents cause inflammatory diarrhea?
C diff Salmonella Shigella Campylobacter E. coli 0157:h7
What is the main symptom in a c diff infection?
Diarrhea
What are the major risk factors to an infection with c diff
Previous antibiotic usage
Advanced age
Previous hospitalization
Nursing home resident
What antibiotics are known for causing a c diff infection
Clindamycin
Penicillins
Cephalosporins
Fluroquinolones
What makes the diagnosis under the new guidelines for c diff?
Presence of symptoms in the form of three or more unformed stool over 24 hours for 2 consecutive days in conjunction with positive stools for pseudomembranes
Prior antibiotic usage in not included in making the diagnosis with the new guidelines
What are the clinical findings in a c diff infection?
Water diarrhea 15-30 bowel movements per day Abdominal pain or cramps Low grade fever Can lead to toxic mega colon and Colectomy
What are the lab findings in c diff?
Leukocytosis- often with bandemia (left shift)
Hypoalbuminemia
Positive stool c diff test
What are the lab tests for c diff?
Molecular test- PCR
Antigen detection
Toxin testing
What lab test for c diff is highly sensitive and specific and can be positive in asymptomatic patients?
Molecular test PCR
Which lab test for c diff is nonspecific?
Antigen detection
Which lab test for c diff is associated with high rates of false negatives?
Toxin A and B testing, used for screening
For an initial episode of c diff that is mild/moderate what do you expect to see on labs?
Leukocytosis <15,000, creatinine <1.5
For an initial episode of c diff with mild to moderate symptoms, what should you use to treat?
Vancomycin 125mg po qid X 10 days OR
Fidaxamin 200 mg po bid X 10 days
For an initial episode of c diff that is severe, what labs would you expect to see?
Leukocytosis >15,000, creatine >1.5 prior to CDI
For an initial episode of c diff with complications, what clinical signs will you see?
Hypotension
Shock
Perforation
Megacolon
What should you use to treat an initial episode of c diff that is complicated?
Vancomycin 500mg po qid or via NG tube and or metronidazole 500-750 mg IV q 8 hours
What should you use to treat the 1st recurrence of c diff?
Vancomycin oral taper or Fidaxamin 125mg po qid
What should you use to treat a 2nd recurrence of c diff?
Vancomycin oral taper or Fidaxamin
Fecal mircobiota transplant
What can be done to prevent c diff infections?
Antibiotic stewardship
Environmental control, hand hygiene
When wanting to prevent c diff, it is important to remember that spores can live up to ___ months on a surface
5
When thinking about preventing a c diff infection, it is important to remember that _____ can be a vector
Health care workers
Are alcohol hand preps effective for preventing c diff?
No
What should be used on surfaces to prevent the transmission of c diff?
Chlorine based disinfectants
Salmonella is a gram negative/ positive rod
Gram negative rod
Salmonella is carried in the GI tract of….
Reptiles and birds
How many cases of salmonella infections yearly in the US?
3.7 million
How do most cases of salmonella occur?
From eating contaminated meat or eggs or from infected food handlers
Also associated with handling reptiles
Patients with a salmonella infection can remain culture positive for ___ months after treatment, making them a long term carrier
1 month
How long is the incubation for salmonella?
6-48 hours
What are the clinical sxs of salmonella?
Fever and diarrhea most common sxs
Usually self limited
Bloody stools uncommon
Where can salmonella spread to?
Vascular grafts, joints, kidneys and liver common in bacteremic patients
What is the treatment of salmonella?
Most cases are self-limiting, if uncomplicated no antibiotic treatment is necessary
Ciprofloxacin treatment of choice
Bactrim (trimeth/sulfa) alternate
What agent causes typhoid fever?
Salmonella typhi
What is important to making the diagnosis of typhoid fever?
Typhoid fever is NOT endemic to the US- travel history is vital for diagnosis
Where are high risk areas for typhoid fever?
India
Pakistan
Caribbean
Mexico
How is typhoid fever transmitted?
By contaminated food, sewage, and infected food handlers (could be asymptomatic carriers)
What are the symptoms of typhoid fever?
Diarrhea Constipation Skin rash on torso and back Fever Abdominal pain Weakness
How is the diagnosis of typhoid fever made?
Stool culture
What is the treatment for typhoid fever?
Antibiotic resistance is an issue
Historic treatment is fluoroquinolones- cipro
Ceftriaxone resistance is developing
Due to resistance issues, current recommendation is azithromycin for mild, carbapenems for more severe cases with history of travel to SE Asia
What is the prognosis of typhoid fever?
It is a serious infection that can be fatal, especially if ineffective treatment due to antibiotic resistance
Shigella is a gram…
Gram negative rod
What organism is commonly referred to as “dysentery” ?
Shigella
Carriers of shigella are symptomatic/asymptomatic
Asymptomatic
Is shigella virulent?
Yes, only 10-100 organisms can cause infection
How is shigella spread?
Person to person
Fecal to oral spread, also flies and inanimate objects
How many worldwide deaths per year can be attributed to shigella?
650,000 deaths worldwide
What is the incubation period for shigella?
12 hours to 4 days
What are the symptoms of shigella?
Diarrhea that is bloody, watery, pus and mucus- secretory Fever Stomach cramps Nausea Vomiting Dehydration
What should be on your differential when making the diagnosis of shigella?
Other bacterial infections such as vibrio
Viral
Parasites
What is the treatment for shigella?
Rehydration
Ciprofloxacin
Bactrim or azithromycin alternate (recent strains show high rate of resistance)
Campylobacter is a gram…
Negative rod
What is the #1 cause of food-borne illness in the US?
Campylobacter- sausages and hard meats, undercooked chicken
What illness often has a prodrome of fever, headache, myalgia, and malaise?
Campylobacter
What are the sxs of campylobacter?
Prodrome- fever, headache, myalgia, and malaise
Diarrhea
Fever
Symptoms are often low grade
What is the treatment for campylobacter?
Ciprofloxacin 1st
Azithromycin 2nd
What are some complications from a campylobacter infection ?
Bacteremia in <1%
Guillian Barre
Reactive arthritis
What is the main cause of HUS in the US?
E. coli 0157: H7
What is an infection with E. coli 0157:H7 linked to?
Undercooked ground beef, drinking of unpasteurized juices and milk, working with cattle (1% of cattle in the US are carriers)
What are the symptoms of an infection with E. coli 0157:H7?
Bloody diarrhea
Severe cramping
Fever 0-30% of the time
Nausea vomiting common
What are you going to see in hemolytic uremic syndrome?
Acute renal insufficiency
Hemolytic anemia
Thrombocytopenia
What populations is HUS severe in?
Children and elderly
HUS can/cannot be fatal?
Can be fatal
What test differentiates TTP from HUS?
ADAMTS 13 test differentiates TTP from HUS
+ in TTP
What labs are you going to see in HUS?
Blood cultures are often negative Anemia Decreased haptoglobin and increased LDH Negative Coombs (nothing coating RBCs) Thrombocytopenia Elevated creatinine Hematuria, proteinuria
What is the treatment for HUS?
Supportive
Antibiotic use is controversial
What is the mortality rate associated with HUS?
5-20% mortality
What agents are responsible for non inflammatory diarrhea?
Staph toxin Bacillus cereus Listeria monocytogenes Enterotoxigenic e Coli Vibrio cholera Norovirus Protozoal infections such as giardia, amoeba
Staph food poisoning is actually from the ____ not the bacteria
Toxin
Staph food poisoning is more common in foods with….
High salt or sugar content (cream sauces, custard, hams, canned meat)
Staph food poisoning onset is fast/ slow
Fast onset- 4-8 hours
What are the symptoms of staph food poisoning?
Cramping, diarrhea, nausea, vomiting
What is the treatment for staph food poisoning?
Usually self limited- antibiotics are not recommended, resolves quickly
Listeria monocytogenes is/ is not foodborne
Is typically food borne
What populations are more susceptible to a listeria monocytogenes infection?
Pregnancy
Immunosuppressed
What can happen when a pregnant woman becomes infected with listeria monocytogenes?
Spontaneous abortion, sepsis
What can result from a listeria monocytogenes infection?
Bacteremia and meningitis
Listeria is a gram…
Positive rod/ bacillus
What is a predisposing risk factor to a listeria infection?
Previous corticosteroid infection
In pregnancy related infections with listeria, ___% of cases end in fetal death
Listeria
Symptoms of listeria…
Fever Chills Muscle aches Nausea Diarrhea
What is treatment of choice in a listeria infection and why?
Ampicillin because it can cross the blood brain barrier to treat meningitis
How does Enterotoxigenic E. coli compare to E. coli 0157:h7?
Not the same infection
Usually less severe when compared to 0157 infection
What organism is the main cause of traveler’s diarrhea?
Enterotoxigenic E. coli
Enterotoxigenic E. coli can be…
A shiga toxin producer but not usually
What are the symptoms of an infection with Enterotoxigenic E. coli?
Profuse diarrhea, usually not bloody
Fever
Abdominal cramping
How is Enterotoxigenic E. coli diagnosed?
By stool culture or PCR
What are the treatment options for Enterotoxigenic E. coli?
Cipro 500 mg po bid X 7 days or
Trimeth/sulfa 180/800 mg po bid x 7 days or
Azithromycin 250mg 2 po on day 1 then 1 po day 2-5
Vibrio cholera is a ____borne illness
Waterborne
The usual cause of vibrio cholera is…
Poor water sanitation
What food carrier vibrio cholera?
Contaminated shellfish - raw oysters
What enterotoxin results in a massive secretion from the small bowel?
Vibrio cholera
What is the incubation time of vibrio cholera?
12-72 hours after ingestion
What are the symptoms of cholera?
Rapid dehydration- profuse watery diarrhea because you lose 1-3 liters per day up to 20 liters per day
What infection is associated with “rice water stools” ?
Cholera
Is fever common with cholera?
No, fever is rare
What is the mortality rate associated with cholera?
1-10%
What is the treatment for cholera?
Hydration!
Doxycycline or cipro Can limit the duration of the disease but dehydration is the main issue
What is viral gastroenteritis?
Inflammation of the stomach and intestinal tract
How many cases of viral gastroenteritis are there each year?
211-375 million
What are the sxs of viral gastroenteritis?
Sudden onset, rapid resolution Diarrhea Nausea Vomiting Stomach cramping
What is the most common cause of non bacterial acute gastroenteritis?
Norovirus
Norovirus persists in the environment/ does not persist in the environment
Persists in the environment and is hard to eradicate
Where do outbreaks of Norovirus commonly occur?
Nursing homes, hospitals, schools, day cars, military bases, cruise ships, hotels
How is Norovirus transmitted?
Person to person contact, contaminated food and water, airborne
Small doses can lead to infection
Contagious even after symptoms resolve- may shed up to several weeks
What are the clinical findings of Norovirus?
Sudden onset of vomiting, diarrhea Nausea Fever Abdominal cramping 1-3 days
What is the treatment for Norovirus?
Self limiting- supportive care
What is the prevention of Norovirus?
Hand washing at least 20 seconds with soap and water
Decontamination of surfaces with beach 10%
Infected food handlers must stay away from work for 48-72 hours after symptoms resolve
For all of these GI illnesses, what is the gold standard testing?
Stool testing, 48-72 hour turn around time
PCR is now available for GI pathogens- good sensitivity for multiple pathogens but expensive
Fever is/ is not always present in diarrheal illnesses
Is not
What needs to be considered when treating with an anti diarrheal/ anti motility agents?
Is the cause inflammatory or non inflammatory
