Dr. Karatzios -- Diarrhea Flashcards Preview

Block G -- Infection > Dr. Karatzios -- Diarrhea > Flashcards

Flashcards in Dr. Karatzios -- Diarrhea Deck (84)
1

Definition of diarrhea (3)

  • Stool weight > 200 g/day
  • ≥ 3 loose or watery stools per day
  • Decreased conmsistency and increased frequency from an individual baseline

2

3 types of diarrhea and their duration

  • Acute: ≤ 14 days duration
  • Persistent (subacute): > 14 days duration
  • Chronic: > 30 days duration

3

7 effects of diarrhea

  • Dehydration (water loss)
  • Salt imbalances (esp Na+ or K+)
  • Acidoses (bicarb losses)
  • Hemorrhage (if dysentery)
  • Chronic anemia (hematochezia)
  • Malnutrition
  • Sepsis (due to perforation or bacterial translocation into blood)

4

10 bacterial pathogens causing infectious diarrhea in the developed world

  • E. coli
  • Salmonella spp.
  • Shigella spp.
  • Yersinia enterocolitica
  • Campylobacterer jejuni
  • Clostridium difficile
  • Clostridium perfringens
  • Listeria monocytogenes
  • Vibrio spp.
  • Bacillus cereus

5

2 types of E. coli causing diarrhea

  • Enterohemorrhagic (EHEC)
    • O157:H7
  • Enterotoxin (ETEC)

6

2 types of Salmonella spp. causing diarrhea

  • Non-typhi
  • Typhi

7

7 viral causes of diarrhea in the developed world

  • Calicivirus/Norovirus (Norwalk-like)
  • Rotavirus
  • Astrovirus
  • Coronavirus (SARS)
  • Adenovirus
  • HIV
  • Influenza virus (seen in pandemic 2009 strain)

8

8 protozoal causes of diarrhea in the developed world

  • Giardia lamblia
  • Cyclspora cayetansis
  • Cryptosporidium spp.
  • Microsporidium spp.
  • Isospora belli
  • Entamoeba histolytica
  • Dientamoeba fragilis
  • Blastocystis hominis

9

5 purely toxin-mediated bacterial pathogens causing diarrhea in the developed world

  • Enterotoxigenic E. coli (Traveller's diarrhea)
  • Staphylococcus aureus enterotoxin
  • Bacillus cereus enterotoxin, among others
  • Vibrio spp
  • C. difficile

10

5 bacterial causes of infectious diarrhea in the developing world (or "imported" diarrhea)

  • Salmonella typhi
  • Shigella spp.
  • Entertoxigenic E. coli
  • Vibrio parahaemolyticus
  • Vibrio cholerae

11

4 viral causes of infectious diarrhea in the developing world (or "imported" diarrhea)

  • Norovirus
  • HIV
  • Influenza virus (2009 pandemic)
  • SARS Coronavirus

12

4 protozoal causes of infectious diarrhea in the developing world (i.e. "imported diarrhea)

  • Giardia lamblia
  • Entamoeba histolytica
  • Microsporidium spp.
  • Isospora belli

13

Usual origin of infectious diarrhea in North America

Viral

14

Visibly bloody stool in North American diarrhea is a good predictor for what kind of pathogen?

Bacterial (especially EHEC)

15

5 bacterial causes of dysentery

SSCYE

  • Shigella spp.
  • Salmonella spp.
  • Campylobacter jejuni
  • Yersinia enterocolitica
  • E. coli O157

16

Viral causes of dysentery 

None really, except perhaps adenovirus in immune suppressed patients (i.e. BMT)

17

Parasitic cause of dysentery

Entamoeba histolytica

18

EHEC: type of bacteria

Gram negative enteric rods containing a toxin created by a viral plasmis inside the cell

19

Reservoir of EHEC

Mammalian GIT

20

Most common cause of acute kidney failure in children

EHEC

21

Describe the progression of EHEC infection

  1. Enteritis about 1 - 2 days after infection
  2. Lasts for about 5 - 10 days
  3. Usually self-limiting
  4. 2 - 7% develop Hemolytic Uremic Syndrome (HUS)

22

3 symptoms of EHEC enteritis

  • Severe cramps
  • Very bloody diarrhea
  • NO fever

23

Cause of HUS in EHEC

Shigatoxin

24

7 signs and symptoms of HUS in EHEC

  • Renal failure
  • Consumptive thrombocytopenia
  • Vascular hemolysis (shearing of RBCs called schistocytes/schizocytes)
  • Stupor
  • Confusion
  • Seizures
  • Worsens with antibiotic therapy (release of toxin)

25

Type of bacteria: Salmonella spp

Gram negetive enteric rods

26

Resrvoirs of Salmonella spp.

Poultry and reptile GIT

27

Describe the progression and symptoms of Salmonella infection

  • Need about 105 bacteria to cause disease
  • Diarrhea (usually bloody), abdominal cramps, and fever 2 days after infection
  • Lasts about 1 week

28

Most serious form of Salmonella infection

Typhoid fever

29

Cause of typhoid fever

Salmonella enterica serogroup typhi

30

9 signs and symptoms of typhoid fever

  • Dissemination to various organs (i.e. blood, liver, etc)
  • High fever
  • Stupor
  • Cramps
  • Bloody diarrhea
  • Blood sepsis
  • Fleeting rose spots on skin
  • Left shift leukopenia
  • Bradycardia

31

What is Salmonella infection recurrence linked to?

Presence of biliary stones

32

Shigella spp: Type of bacteria

Gram negative enteric rods

33

Only reservoir of Shigella spp

Primates

34

Describe the progression of Shigella infection

  • Need ~10 bacteria to cause disease
  • Symptoms 1 - 2 days after infection
  • Lasts about 1 week
  • Highly contagious

35

7 signs and symptoms of Shigella infection


  • High fever 



  • Stupor 





  • Cramps 







  • Dysentery (black currant, jelly-like stools 









  • Seizures due to shigatoxin 











  • Sometimes HUS 













  • Reactive arthritis
     

36

Campylobacter jejuni: type of bacteria

Curved gram negative enteric rods

37

Reservoir of Campylobacter jejuni

Bird GIT

38

Most common cause of bloody diarrhea in a daycare setting and one of the most common causes of enteritis due to food poisoning

Campylobacter jejuni

39

Describe the symptoms (3) and progression (4) of Campylobacter jejuni infection

  • Enteritis starting about 2 days after infection
    • Cramps
    • Diarrhea may be bloody
    • Sometimes HUS
  • Usually self-limiting; Lasts for about 1 week
  • Guillain-Barre syndrome after about 2 - 3 weeks
  • Highly contagious

40

Yersinia enterocolitica: Type of bacteria

Gram negative enteric rod that loves iron (uses it as a growth factor)

41

4 Risk factor for Yersinia enterocolitica infection

  • High iron states
  • Eating undercooked meat
  • Drinking unpasteurized milk
  • Fecal-oral contact

42

Reservoir of Yersinia enterocolitica

Various mammals (zoonosis)

43

Describe the general progression of yersinia enterocolitica infection (5)

  • Starts within a week after infection
  • Lasts 1 - 3 weeks
  • Sepsis and bacteremia in immune suppressed people
  • Different manifestations between young children and older children/adults
  • Post infectious arthritis

44

3 manifestations of yersinia entercolitis in young children

  • Bloody diarrhea
  • Terminal ileitis
  • Mesenteric adenitis

45

Manifestation of yersinia enterocolitica infection in older children and adults

Severe abdominal cramps that may mimic appendicitis (pseudoappendicitis)

46

5 signs and symptoms of Entamoeba histolytica infection

  • Bloody diarrhea
  • Cramps
  • Fever
  • Abscesses if dissemination to liver, lungs and brain (often in immunosuppressed)
  • Amoeboma

47

Define amoeboma

Large mass in intestine that can be mistaken for a tumor but is really a granuloma due to amoebic infection

48

Cause of traveller's diarrhea

ETEC

49

Describe the symptoms and progression of ETEC infection (traveler's diarrhea)

  • Self-limtied disease
  • No fever
  • No systemic illness

50

Describe the progression and symptoms of cholera (vibrio cholerae infection)

  • Severe explosive watery diarrhea (liters and liters lost --> deadly)
    • Rice water stool
  • Highly contagious

51

When can Vibrio vulnificus be acquired?

After eatign shellfish or stepping on a stingray

52

5 signs and symptoms of Vibrio vulnificus infection

  • Diarrhea
  • Vomiting
  • Skin blisters
  • Sepsis
  • Shock

53

Describe the progression of Listeria monocytogenes infection

Watery diarrhea can progress to disseminated disease in immune suppressed people and pregnant women (CNS disease, bacteremia, still births)

54

Clostridium difficile: type of bacteria

Gram-positive anaerobic rod that forms resistant spores (need to be WASHED off hands)

55

Disease caused by C. difficile

C. difficile-associated colitis (CDAD)

56

4 signs and symptoms of CDAD

Toxin-mediated (toxins A and B)

  • Watery diarrhea
  • Colitis
  • Pseudomembranous colitis
  • May progress to toxic megacolon (septic ileus of the colon)

57

Why don't babies <6 months get CDAD?

No receptors for C difficile toxins (develpo between 6 months and 1 year), therefore diarrhea in hospitalized children <6 months is NOT C. diff

58

4 risk factors for CDAD

  • Healthcare
  • Antibiotic use
  • Debilitated conditions (old age comorbidities)
  • PPI's?

59

2 important viral causes of watery diarrhea

Rotavirus

Norovirus

60

Most common cause of self-limited gastroenteritis (i.e. 24h stomach flu or "winter gastro")

Norovirus

61

Usual type of diarrhea caused by parasites

Protracted and chronic

62

3 risk factors for parasitic diarrhea

Travel

Fecal-oral contact (i.e. contaminated food)

Immune suppression

63

Why are the "sporas" (name them) significant causes to remember of parasitic diarrhea

  • Microsporidium spp
  • Cryptosporidium spp
  • Cyclospora cayetanensis
  • Isospora belli

WHY = need special staining to see them

64

5 points of initial management of diarrhea

  1. Evaluate severity and duration
  2. Obtain history and physical exam
  3. Treat dehydration
  4. Report suspected outbreaks
  5. Determine whether it is:
    1. Community-acquired/traveler's diarrhea
    2. Nosocomial
    3. Persistent

65

3 points of management if diarrha is community-acquired or traveler's diarrhea

  • Consider quinolone for suspected shigellosis in adults (fever, inflammation)
  • Macrolide for suspected resistant Campylobacter
  • Avoid antimotility or certain antimicrobial drugs if suspected STEC (afebrile, bloody diarrhea)

66

2 points of management for nosocomial diarrhea

  • Discontinue antimicrobial if possible
  • Consider metronidazole if illness worsens or persists

67

Viral, non-bloody diarrhea with vomiting (3 causes)

  • Norovirus (esp if 24 - 48 hours)
  • Adenovirus
  • Astrovirus

68

Non-bloody viral diarrhea without too much vomiting

Rotavirus

69

Turnover in lab for stool culture

24 - 48 hours; final ID and sensitivity in 72 hours

70

4 cases where stool cultures are UNHELPFUL

  • ETEC (self-limited traveler's diarrhea)
  • Self-limited Yersinia enterocolitica infections
  • Self-limtied non-typhoid Salmonellosis
  • Diarrhea after 3 days in hospital (think C. diff)

71

4 cases where stool cultures are HELPFUL

  • EHEC (development of HUS)
    • Use of antibiotics may worsen renal failure
  • Public Health purposes 
    • Shigella spp
    • Salmonella typhi, Vibrio cholerae, outbreak situation (Campylobacter spp infections in daycares)
  • When treatment will help
  • Help in diagnosis of Guillain-Barre syndrome

72

6 cases where stool culture should be sent as a diagnostic test

  • Severe diarrhea (i.e. bloody, extremely large quantity)
  • Immunocompromised patients
    • HIV, <3 months or >65 years age
  • Patients with comorbid conditions (i.e. renal failure)
  • Patients with IBD
  • Food handlers and health care workers (Public health purposes)
  • Patients with Guillain-Barre syndrome

73

2 diagnostic techniques to detect toxins A and/or B

  • Enzyme immunoassay
  • PCR

74

Only viral diagnostic test that is currently widely available and used

Rotavirus test

75

4 points of diagnostic testing for parasitic causes

  • At least 3 stools are required (different bowel movements) since parasites and their eggs are shed intermittently
  • Usually iodine-based staining techniques (NOTE: not for the sporas)
  • Lab diagnosis based on morphology
  • Results depend on how fast lab technician can get to specimens (a few days)

76

8 situations where antibiotics SHOULD be used to treat diarrhea

  • Suspected or confirmed typhoid fever
  • Salmonella typhi in stool specimen
  • Shigella spp
  • Campylobacter spp infection
  • Bacteremia with any bacterial pathogen
  • Traveler's diarrhea
  • Symptomatic C. diff colitis
  • Parasitic-related diarrhea

77

3 cases where Ciprofloxacin po/IV or Ceftriaxone IV are used as treatments

  • Suspected or confirmed yphoid fever
  • Salmonella typhi in stool specimen
  • Shigella spp

78

2 treatment options for traveler's diarrhea

  • Ciprofloxacin po
  • Azithromycin po

79

3 treatments for symptomatic C. difficile colitis

  • Metronidazole (Flagyl) po/IV
  • Vancomycin po
  • Enema with "healthy" stool

80

What to treat with the "sporas"

Since available treatments are not very good and they occur primarily in immunosuppressed patients, treat the immune suppression

81

3 situations where you DO NOT give antibiotics as treatment

  • Suspected or proven EHEC infections
  • Well-looking and non-bacteremic non-typhi Salmonella spp
  • Bloody diarrhea and systemically ill patients

82

Why don't you give antibiotics in suspected or proven EHEC infection?

May worsen renal failure and HUS

83

Why don't you give antiobiotics for well-looking and non-bacteremic non-typhi Salmonellosis?

Risk for prolonged shedding of organisms

84

Why not give antibiotics for bloody diarrhea and systemically ill patients?

Better to "flush things out" rather than let it fester in the intestines for potential invasion