ICL 15.3: Noninflammatory and Inflammatory Diarrhea Flashcards
what is official definition of diarrhea?
3+ unformed stools daily or quantity > 250 grams daily
less than 14 days is considered acute; 14 to 30 days is persistent; 30+ days is chronic
what is the presentation of acute infectious diarrhea?
acute infectious diarrheal presentations include acute gastroenteritis
patients may present with associated fever, nausea, vomiting, flatulence, tenesmus, and crampy abdominal pain
what is the common cause of chronic infectious diarrhea?
usually parasites
which diarrheal presentations aren’t infectious?
- inflammatory bowel disease
- endocrine disorders
- celiac disease
- irritable bowel syndrome
- medication induced diarrhea
who needs hospitalized for diarrhea?
- mucoid or bloody diarrhea, fever, significant abdominal cramping, suspected sepsis, immunocompromised hosts
- symptoms that persist for longer than 1 week
- outbreak settings where day-care participants, institutional residents, health care providers, or food handlers are involved
- diagnostic assessment of stool to guide antimicrobial use
how do you diagnose diarrhea?
- rapid multiplex molecular gastrointestinal assays
- identify common bacterial, parasitic, and viral pathogens from a single stool sample
generally more sensitive than stool culture and microscopy with special stains
isolates from culture can provide antibiotic susceptibilities and strain-typing information in outbreak situations that are not available from culture-independent diagnostic assays
how do you treat diarrhea?
- healthy patients with watery diarrhea of less than 3 days’ duration are treated with supportive care; no antibiotic therapy or diagnostic assessment
- when acute diarrhea is debilitating (moderate or severe) and/or associated with travel give antibiotics with fluoroquinolone, azithromycin, or rifaximin
- dysentery with visible mucus or blood in the stool, temperature < 37.8 °C - microbiologic assessment recommended to guide therapy
- in severe debilitating disease with temperatures of > 38.4 °C, microbiologic assessment should be considered followed by empiric azithromycin
antimotility agents (loperamide) are discouraged in patients with inflammatory diarrhea (fever, abdominal pain, bloody stools) orClostridium difficile–associated infection** –> anti motility agents could lead to bowel perforation!!
what is a campylobacter infection?
gastroenteritis is usually foodborne
often secondary to consumption of inadequately cooked poultry*
incubation period is several days
symptoms include diarrhea (visibly bloody in <15% of patients), crampy abdominal pain, and fever
stool culture can confirm the diagnosis
how do you treat a campylobacter infection?
diarrhea usually resolves spontaneously without antibiotics
patients with severe disease (bloody stools, bacteremia, high fever, >1 week symptoms) or immunocompromised should receive antibiotics
macrolide therapy preferred empirically –> there’s an increasing fluoroquinolone resistance
what are the possible pos-campylobacterinfection complications?
- irritable bowel syndrome
- reactive arthritis
- Guillain-Barré syndrome
what is a shigella infection?
more commonly spread from person to person than by consumption of contaminated food or water
fewer than 100 bacteria can cause infection so you dont need a lot of exposure to get it
incubation period is approximately 3 days
symptoms:
1. crampy abdominal pain
- tenesmus, small-volume bloody and/or mucoid diarrhea
- high fever
- vomiting
what are the complications associated with shigella infection? post-infectious sequelae?
- bacteremia
- seizures
- intestinal obstruction
- perforation
POST-INFECTIOUS
1. HUS
- reactive arthritis
- irritable bowel syndrome
how do you diagnose shigella infection?
routine stool culture or molecular testing
blood cultures may help with invasive disease in patients with severe infection
how do you treat shigella?
antibiotics are recommended for severe illness (hospitalized patients, invasive disease, or complications of infection) and immunocompromised
public health officials may recommend treatment when outbreaks occur
antibiotic susceptibilities should be obtained to determine treatment –> increasing resistance rates against the quinolones
what are the different types of salmonella infections?
TYPHOIDAL
1. enteric fever = syndrome consisting of fever, abdominal pain, rash, hepatosplenomegaly, and relative bradycardia
- uncommon in the United States
- affected persons travel to endemic areas and ingest contaminated water or food
NONTYPHOIDAL
1. most common bacterial cause of foodborne illness in the United States
- ingestion of fecally contaminated water or food of animal origin: poultry, beef, eggs, and milk
- contact with infected animals (pet reptiles, turtles, and snakes; farm animals; amphibians; rodents) = less common mode of transmission
what is a salmonella infection?
incubation period <3 days
symptoms
1. cramps abdominal pain
- fever
- diarrhea (not usually visibly bloody)
- headache
- nausea
- vomiting
how do you diagnose a salmonella infection?
stool culture or molecular testing
how do you treat a salmonella infection?
usually self limiting
however sometimes bacteremia with extraintestinal infection can occur and cause vascular endothelium, joints, meninges
so antibiotic are reserved for serious illness like patients with severe diarrhea requiring hospitalization, bacteremia, or high fever/sepsis –> also give antibiotics to people with high risk for severe complicated invasive disease aka infants, adults >50 years, patients with prosthetic materials, atherosclerotic disease, immunocompromising conditions
fluoroquinolones likely to be effective! azithromycin, trimethoprim-sulfamethoxazole, and amoxicillin can also be used –> local antibiotic susceptibilities should dictate choice of empiric therapy
what are the associations of salmonella infections?
- salmonellaosteomyelitis – classically associated with sickle cell disease
- common in severe invasive disease - infants, older adults, cell-mediated immunodeficiency
- reactive arthritis is a potential post-infection complication
what is enterotoxigenic e. coli infections?
most common cause of travelers’ diarrhea
ingestion of water or food contaminated with stool
incubation period of 1 to 3 days
enterotoxins cause watery diarrhea
associated abdominal cramping, nausea, and low-grade or no fever
how do you treat enterotoxigenic e. coli infections?
usually self-limiting; resolves after approximately 4 days and doesn’t require antibiotics
hydration and empiric antibiotic therapy with fluoroquinolones, azithromycin, or rifaximin in travelers when symptoms restrict activities
what are enterohemorrhagic e. coli infections?
enterohemorrhagicE. colistrains (such as -0157:H7 and -0104:H4) produce a Shiga-like toxin that can cause hemorrhagic colitis
found in cow intestines so you can get it from ingestion of undercooked hamburgers or fecally contaminated food like spinach, lettuce, fruit, milk, and flour and water
you can also get it from fecal-oral transmission through exposure to infected animals at petting zoos possible
incubation period is 3 to 4 days
visibly bloody diarrhea, crampy abdominal pain, and NO fever
what is a potential complication of enterohemorrhagic e. coli infections?
alerting the laboratory about the symptoms recommended because there is appropriate media, antigen testing, and Shiga toxin assays that can be performed!
patients can develop hemolytic uremic syndrome in <10% of patients but it manifests as microangiopathic hemolytic anemia, thrombocytopenia, and kidney injury
how do you treat enterohemorrhagic e. coli infections?
supportive
DONT give antibiotics!! they may increase the risk of developing hemolytic-uremic syndrome and do not appear to shorten the duration of infection
what is a yersinia enterocolitica infection?
most diarrheal illness caused byYersinia enterocolitica
usually after ingestion of contaminated food (undercooked pork)
patients with iron overload states, including hemochromatosis, are at increased risk for infections, including bacteremia
incubation period is approximately 5 days
symptoms
1. abdominal pain, diarrhea (possibly bloody)
- sometimes nausea and emesis at presentation
what is the tropism of yersinia entercolitica?
it has a tropism for lymphoid tissue like tonsillar tissue, mesenteric lymph node
this results in pharyngitis or right lower-quadrant pain mimicking appendicitis
what are the post infectious complications associated with yersinia entercolitica?
- erythema nodosum
2. reactive arthritis
how do you diagnose yersinia entercolitica?
molecular testing of stool or by culture of stool, blood, a throat swab, or infected tissue
lab should be alerted whenYersinia enterocoliticainfection is suspected
how do you treat yersinia entercolitica infections?
trimethoprim-sulfamethoxazole
fluoroquinolone or third-generation cephalosporin are good alternatives
what is a vibrio parahaemolyticus infection?
most commonVibriospecies to cause gastrointestinal illness
consumption of contaminated or undercooked oysters and other shellfish
incubation period approximately 1 day
symptoms
1. diarrhea (not commonly bloody)
- fever
- nausea or emesis
- crampy abdominal pain
- may lead to secondary necrotizing skin infections
* septicemia in patients with liver disease so watch out for patients with liver problems who have eaten oysters
how do you treat a vibrio parahaemolyticus infection?
this is a severe noninvasive gastrointestinal illness so it gets treated with doxycycline
fluoroquinolones and macrolides also can be used
if the patient develops septicemia treat with a more aggressive combination therapy, typically with doxycycline plus ceftriaxone
what is a clostridiodes difficile infection?
leading cause of hospital-acquired infectious diarrhea
results from fecal-oral transmission
number of infections in the U.S. has increased significantly since 2000 due to mergence of a hypervirulent strain
antibiotic stewardship is paramount in reducing incidence of infection –> c. diff is the reason people don’t give antibiotics for viral illnesses!
asymptomatic colonization can occur and incubation period can be as long as 6 weeks after antibiotics
community-acquired infections without previous exposure to health care settings, antibiotic agents, or both have been increasingly reported
hand washing with soap and water – gold standard for infection control because alcohol-based gels do not eliminate spores!
what are the risk factors for getting a clostridiodes difficile infection?
- antibiotic and chemotherapeutic agents
- older age
- inflammatory bowel disease
- GI surgery
- proton pump inhibitors
what makes clostridiodes difficile infectious?
it produces both an enterotoxin (toxin A) and a cytotoxin (toxin B) that are pathogenic
what are the symptoms of a clostridiodes difficile infection?
- watery diarrhea (rarely bloody)
- crampy abdominal pain
- malaise
- sometimes nausea and fever
what are the lab results for a person with a clostridiodes difficile infection?
- leukocytosis
- elevated creatinine
- hypoalbuminemia
how can you diagnose a clostridiodes difficile infection?
you need to test unformed stools from persons who have unexplained new-onset diarrhea occurring three or more times daily
- Enzyme immunoassay (EIA) testing –> highly specific and rapid, but EIA testing for presence of toxin A or B lacks sensitivity –> there’s also EIA testing for glutamate dehydrogenase, an antigenic protein present in allC. difficileisolates, is quite sensitive but lacks specificity
- nucleic acid amplification testing (NAAT) forC. difficiletoxin genes** –> Rapid, highly sensitive, and specific
- radiographic imaging is nonspecific but may demonstrate colonic wall thickening, mucosal edema, fat stranding, and megacolon
- colonoscopy may visualize pseudomembranes associated with infection but this is not a routine diagnostic modality
how do you treat a clostridiodes difficile infection?
in all patients, the antibiotic associated with the infection should be stopped if possible
treatment is otherwise dictated by severity of disease
- severe disease (leukocyte count > 15,000/µL, or serum creatinine >1.5 mg/dL)
oral vancomycin or fidaxomicin for 10 days
- fulminant disease (severeC. difficileinfection with associated shock, ileus, toxic megacolon, ICU admission, elevated serum lactate level, hypotension, altered mental status, organ failure)
high-dose oral or nasogastric vancomycin, intravenous metronidazole, vancomycin enema when ileus is present – warrant surgical evaluation
- non-severe disease
oral vancomycin or fidaxomicin for 10 days; possibly oral metronidazole for 10 days
why is treating clostridiodes difficile infection complicated?
recurrent infection is reported in as many as 25% of patients
fecal microbiota transplantation effective in patients with multiple recurrences
retesting stool forC. difficileafter treatment for evidence of cure in patients who have no symptoms is not recommended
what is viral gastroenteritis?
viruses are responsible for acute gastroenteritis in most patients
patients present with watery diarrhea, nausea, vomiting, and fever
which viruses are most likely the cause of acute gastroenteritis?
- rotavirus (infants)
- norovirus (all ages; very common in school aged kids)
estimated to cause more than 50% of foodborne gastroenteritis in the United States –> outbreaks on cruise ships and in schools and other institutionalized settings
how is viral gastroenteritis transmitted?
transmission from person to person is primarily fecal-oral
highly contagious infection can develop after ingestion of fewer than 100 viral particles
incubation period is typically less than 2 days
how do you diagnose viral gastroenteritis?
usually self-limited and requires supportive care
viral shedding persists for as long as 2 weeks after symptom resolution which contributes to the high infectivity!
what is a giardiasis lambda infection? how is it spread?
most common parasitic pathogen in the United States
cysts from infected animals are excreted in stool into reservoirs of natural fresh water; subsequent ingestion of contaminated water or food can lead to human infection –> secondary spread from person to person via fecal-oral transmission is also possible because cysts may be excreted for many months
1-3 week incubation
who is at risk for a giardia infection?
- international outdoor travelers
- children in day cars
- immunocompromised
what are the symptoms of giardia lamblia infections?
- watery diarrhea (fatty, foul smelling)
- flatulence
- bloating
- nausea
- crampy abdominal pain
fever is uncommon
symptoms can last for several weeks until spontaneously resolving; chronic infection may develop (particularly with hypogammaglobulinemia)
how do you diagnose giardia lamblia infections?
stool EIA and molecular testing (better than microscopy)
how do you treat giardia lamblia infections?
treatment is recommended for symptomatic patients
metronidazole*, tinidazole, or nitazoxanide can be used
post-infection lactose intolerance is common which may be mistaken for recurrent or resistantGiardiainfection
what is a cryptosporidium infection?
cryptosporidiumspecies can infect humans and other mammals.
infection occurs through consumption of fecally contaminated water or food or through close person-to-person or animal-to-person transmission
municipal water supplies and swimming pools can be a source of infection; thick-walled oocysts are chlorine resistant and can evade filtration
highly infectious; ingestion < 50 oocysts may result in infection
incubation period is 7 days
what are the symptoms of a cryptosporidium infection?
- watery diarrhea
- crampy abdominal pain
- nausea/vomiting
- malaise
- fever
- dehydration
- weight loss
some may be asymptomatic; symptoms usually last less than 2 weeks before spontaneously resolving in immunocompetent hosts
immunocompromised patients can develop serious and prolonged infection
how do you diagnose a cryptosporidium infection?
microscopically by visualization of oocysts with modified acid-fast staining, molecular testing, and enzyme or DFA testing
how do you treat a cryptosporidium infection?
treatment for immunocompetent patients = supportive care
with severe or prolonged infection, nitazoxanide is recommended
in HIV-infected patients, antiretroviral therapy can resolve infection so give nitazoxanide if supportive care does not result in symptom resolution
what organism is responsible for amebiasis?
entamoeba histolytica
what is amebiasis?
in the US, most infections in travelers returning from visits to unsanitary tropical or developing countries, immigrants from these areas, or persons in institutionalized settings
highly infectious – ingestion of only a small number of infective cysts in contaminated water or food needed for infection
incubation period is 2 to 4 weeks
what are the symptoms of amebiasis?
most infections are asymptomatic
some patients develop diarrhea with visible blood, mucus, or both and associated abdominal pain, fever, and weight loss
colonic perforation, peritonitis, and death may complicate more fulminant infections
risk factors for severe infection in adults include immunodeficiency
how do you diagnose amebiasis?
microscopically by visualization of cysts or trophozoites, immunoassay testing, molecular testing, and serologic antibody testing
how do you treat amebiasis?
treatment is recommended for all infected patients
in symptomatic patients, treatment with metronidazole or tinidazole is recommended initially for parasitic clearance followed by an intraluminal amebicide, such as paromomycin or diloxanide, for cyst clearance
in asymptomatic infections, an intraluminal agent for eradication of cysts is recommended
what is a cyclosporine infection? how do you get it?
acquired after consumption of food or water that is fecally contaminated withCyclosporaoocysts
most infections traced to imported fresh produce from tropical areas or have occurred in persons who have traveled to areas of endemicity
incubation period = 1 week
what are the symptoms of a cyclosporine infection?
- watery diarrhea
- decreased appetite
- weight loss
- crampy abdominal pain
- bloating
- flatulence
- nausea
- fatigue
- fever
symptoms can last for several weeks; may be more pronounced in HIV-infected patients
how do you diagnose a cyclosporine infection?
microscopically by visualization of oocysts with modified acid-fast staining, microscopy with ultraviolet fluorescence, or molecular testing
how do you treat a cyclosporine infection?
trimethoprim-sulfamethoxazole recommended for treatment of symptomatic infection
what are probiotics?
some studies say they’re beneficial while others say they’re not
most recently, they say that there is a small benefit and that benefit is probably in decreasing the duration of antibiotic associated diarrhea for a day
probiotics don’t prevent c. diff
there are patients who are immunocompromised, especially BMT patients, who come in with lactobacillus bacteremia from probiotics! so don’t give to these patients
do not give long term probiotics!!
