ICL 15.3: Noninflammatory and Inflammatory Diarrhea

Question 1

what is official definition of diarrhea?

Answer 1

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

Question 2

what is the presentation of acute infectious diarrhea?

Answer 2

acute infectious diarrheal presentations include acute gastroenteritis

patients may present with associated fever, nausea, vomiting, flatulence, tenesmus, and crampy abdominal pain

Question 3

what is the common cause of chronic infectious diarrhea?

Answer 3

usually parasites

Question 4

which diarrheal presentations aren’t infectious?

Answer 4

1. inflammatory bowel disease
2. endocrine disorders
3. celiac disease
4. irritable bowel syndrome
5. medication induced diarrhea

Question 5

who needs hospitalized for diarrhea?

Answer 5

1. mucoid or bloody diarrhea, fever, significant abdominal cramping, suspected sepsis, immunocompromised hosts
2. symptoms that persist for longer than 1 week
3. outbreak settings where day-care participants, institutional residents, health care providers, or food handlers are involved
4. diagnostic assessment of stool to guide antimicrobial use

Question 6

how do you diagnose diarrhea?

Answer 6

1. rapid multiplex molecular gastrointestinal assays
2. 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

Question 7

how do you treat diarrhea?

Answer 7

1. healthy patients with watery diarrhea of less than 3 days’ duration are treated with supportive care; no antibiotic therapy or diagnostic assessment
2. when acute diarrhea is debilitating (moderate or severe) and/or associated with travel give antibiotics with fluoroquinolone, azithromycin, or rifaximin
3. dysentery with visible mucus or blood in the stool, temperature < 37.8 °C - microbiologic assessment recommended to guide therapy
4. 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!!

Question 8

what is a campylobacter infection?

Answer 8

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

Question 9

how do you treat a campylobacter infection?

Answer 9

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

Question 10

what are the possible pos-campylobacterinfection complications?

Answer 10

1. irritable bowel syndrome
2. reactive arthritis
3. Guillain-Barré syndrome

Question 11

what is a shigella infection?

Answer 11

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

2. tenesmus, small-volume bloody and/or mucoid diarrhea
3. high fever
4. vomiting

Question 12

what are the complications associated with shigella infection? post-infectious sequelae?

Answer 12

1. bacteremia
2. seizures
3. intestinal obstruction
4. perforation

POST-INFECTIOUS
1. HUS

2. reactive arthritis
3. irritable bowel syndrome

Question 13

how do you diagnose shigella infection?

Answer 13

routine stool culture or molecular testing

blood cultures may help with invasive disease in patients with severe infection

Question 14

how do you treat shigella?

Answer 14

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

Question 15

what are the different types of salmonella infections?

Answer 15

TYPHOIDAL
1. enteric fever = syndrome consisting of fever, abdominal pain, rash, hepatosplenomegaly, and relative bradycardia

2. uncommon in the United States
3. 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

2. ingestion of fecally contaminated water or food of animal origin: poultry, beef, eggs, and milk
3. contact with infected animals (pet reptiles, turtles, and snakes; farm animals; amphibians; rodents) = less common mode of transmission

Question 16

what is a salmonella infection?

Answer 16

incubation period <3 days

symptoms
1. cramps abdominal pain

2. fever
3. diarrhea (not usually visibly bloody)
4. headache
5. nausea
6. vomiting

Question 17

how do you diagnose a salmonella infection?

Answer 17

stool culture or molecular testing

Question 18

how do you treat a salmonella infection?

Answer 18

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

Question 19

what are the associations of salmonella infections?

Answer 19

1. salmonellaosteomyelitis – classically associated with sickle cell disease
2. common in severe invasive disease - infants, older adults, cell-mediated immunodeficiency
3. reactive arthritis is a potential post-infection complication

Question 20

what is enterotoxigenic e. coli infections?

Answer 20

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

Question 21

how do you treat enterotoxigenic e. coli infections?

Answer 21

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

Question 22

what are enterohemorrhagic e. coli infections?

Answer 22

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

Question 23

what is a potential complication of enterohemorrhagic e. coli infections?

Answer 23

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

Question 24

how do you treat enterohemorrhagic e. coli infections?

Answer 24

supportive

DONT give antibiotics!! they may increase the risk of developing hemolytic-uremic syndrome and do not appear to shorten the duration of infection

Question 25

what is a yersinia enterocolitica infection?

Answer 25

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)

2. sometimes nausea and emesis at presentation

Question 26

what is the tropism of yersinia entercolitica?

Answer 26

it has a tropism for lymphoid tissue like tonsillar tissue, mesenteric lymph node

this results in pharyngitis or right lower-quadrant pain mimicking appendicitis

Question 27

what are the post infectious complications associated with yersinia entercolitica?

Answer 27

1. erythema nodosum

2. reactive arthritis

Question 28

how do you diagnose yersinia entercolitica?

Answer 28

molecular testing of stool or by culture of stool, blood, a throat swab, or infected tissue

lab should be alerted whenYersinia enterocoliticainfection is suspected

Question 29

how do you treat yersinia entercolitica infections?

Answer 29

trimethoprim-sulfamethoxazole

fluoroquinolone or third-generation cephalosporin are good alternatives

Question 30

what is a vibrio parahaemolyticus infection?

Answer 30

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)

2. fever
3. nausea or emesis
4. crampy abdominal pain
5. 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

Question 31

how do you treat a vibrio parahaemolyticus infection?

Answer 31

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

Question 32

what is a clostridiodes difficile infection?

Answer 32

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!

Question 33

what are the risk factors for getting a clostridiodes difficile infection?

Answer 33

1. antibiotic and chemotherapeutic agents
2. older age
3. inflammatory bowel disease
4. GI surgery
5. proton pump inhibitors

Question 34

what makes clostridiodes difficile infectious?

Answer 34

it produces both an enterotoxin (toxin A) and a cytotoxin (toxin B) that are pathogenic

Question 35

what are the symptoms of a clostridiodes difficile infection?

Answer 35

1. watery diarrhea (rarely bloody)
2. crampy abdominal pain
3. malaise
4. sometimes nausea and fever

Question 36

what are the lab results for a person with a clostridiodes difficile infection?

Answer 36

1. leukocytosis
2. elevated creatinine
3. hypoalbuminemia

Question 37

how can you diagnose a clostridiodes difficile infection?

Answer 37

you need to test unformed stools from persons who have unexplained new-onset diarrhea occurring three or more times daily

1. 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
2. nucleic acid amplification testing (NAAT) forC. difficiletoxin genes** –> Rapid, highly sensitive, and specific
3. radiographic imaging is nonspecific but may demonstrate colonic wall thickening, mucosal edema, fat stranding, and megacolon
4. colonoscopy may visualize pseudomembranes associated with infection but this is not a routine diagnostic modality

Question 38

how do you treat a clostridiodes difficile infection?

Answer 38

in all patients, the antibiotic associated with the infection should be stopped if possible

treatment is otherwise dictated by severity of disease

1. severe disease (leukocyte count > 15,000/µL, or serum creatinine >1.5 mg/dL)

oral vancomycin or fidaxomicin for 10 days

2. 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

2. non-severe disease

oral vancomycin or fidaxomicin for 10 days; possibly oral metronidazole for 10 days

Question 39

why is treating clostridiodes difficile infection complicated?

Answer 39

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

Question 40

what is viral gastroenteritis?

Answer 40

viruses are responsible for acute gastroenteritis in most patients

patients present with watery diarrhea, nausea, vomiting, and fever

Question 41

which viruses are most likely the cause of acute gastroenteritis?

Answer 41

1. rotavirus (infants)
2. 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

Question 42

how is viral gastroenteritis transmitted?

Answer 42

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

Question 43

how do you diagnose viral gastroenteritis?

Answer 43

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!

Question 44

what is a giardiasis lambda infection? how is it spread?

Answer 44

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

Question 45

who is at risk for a giardia infection?

Answer 45

1. international outdoor travelers
2. children in day cars
3. immunocompromised

Question 46

what are the symptoms of giardia lamblia infections?

Answer 46

1. watery diarrhea (fatty, foul smelling)
2. flatulence
3. bloating
4. nausea
5. crampy abdominal pain

fever is uncommon

symptoms can last for several weeks until spontaneously resolving; chronic infection may develop (particularly with hypogammaglobulinemia)

Question 47

how do you diagnose giardia lamblia infections?

Answer 47

stool EIA and molecular testing (better than microscopy)

Question 48

how do you treat giardia lamblia infections?

Answer 48

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

Question 49

what is a cryptosporidium infection?

Answer 49

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

Question 50

what are the symptoms of a cryptosporidium infection?

Answer 50

1. watery diarrhea
2. crampy abdominal pain
3. nausea/vomiting
4. malaise
5. fever
6. dehydration
7. 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

Question 51

how do you diagnose a cryptosporidium infection?

Answer 51

microscopically by visualization of oocysts with modified acid-fast staining, molecular testing, and enzyme or DFA testing

Question 52

how do you treat a cryptosporidium infection?

Answer 52

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

Question 53

what organism is responsible for amebiasis?

Answer 53

entamoeba histolytica

Question 54

what is amebiasis?

Answer 54

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

Question 55

what are the symptoms of amebiasis?

Answer 55

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

Question 56

how do you diagnose amebiasis?

Answer 56

microscopically by visualization of cysts or trophozoites, immunoassay testing, molecular testing, and serologic antibody testing

Question 57

how do you treat amebiasis?

Answer 57

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

Question 58

what is a cyclosporine infection? how do you get it?

Answer 58

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

Question 59

what are the symptoms of a cyclosporine infection?

Answer 59

1. watery diarrhea
2. decreased appetite
3. weight loss
4. crampy abdominal pain
5. bloating
6. flatulence
7. nausea
8. fatigue
9. fever

symptoms can last for several weeks; may be more pronounced in HIV-infected patients

Question 60

how do you diagnose a cyclosporine infection?

Answer 60

microscopically by visualization of oocysts with modified acid-fast staining, microscopy with ultraviolet fluorescence, or molecular testing

Question 61

how do you treat a cyclosporine infection?

Answer 61

trimethoprim-sulfamethoxazole recommended for treatment of symptomatic infection

Question 62

what are probiotics?

Answer 62

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!!