Gastroenteritis Flashcards

1
Q

Which gastroenteritis bugs have a 1-6 hr incubation?

A

Staph aureus and bacillus cereus

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2
Q

Which GI bugs have a 8-14 hr incubation?

A

Clostridium perfringens

Bacillus cereus

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3
Q

Which bugs have a 16 hour incubation or longer?

A
  1. cholera
  2. vibrio parahemolyticus
  3. ETEC
  4. Salmonella
  5. Shigella
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4
Q

Common food to get ETEC

A

salad

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5
Q

Easy way to get vibrio parahemolyticus

A

oysters/shellfish

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6
Q

Easy way to get C perfringens:

A

beef/poultry

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7
Q

Easy way to get shigella

A

Potato/egg salad,

Raw veggies

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8
Q

What population is at greater risk for shigella?

A

MSM and daycare populations

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9
Q

What can cause gastroenteritis in a pregnant woman?

A

Listeria

HepE

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10
Q

What does non-inflammatory diarrhea (toxin mediated) look like?

A

Affects the proximal small bowel

Watery stool with no WBCs

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11
Q

What does inflammatory diarrhea look like?

A

Affects the colon
bloody/mucoid appearance
Fecal WBC is elevated

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12
Q

What are some bugs that cause inflammatory diarrhea?

A

Shigella, salmonella
EHEC/EIEC (NOT ETEC)
C difficile
Campylobacter

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13
Q

What causes penetrating diarrhea?

A

Salmonella typhi

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14
Q

What is the definition of diarrhea?

A

3 loose stools in a 24 hr period

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15
Q

At what point is diarrhea considered “persistent”?

A

14 days

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16
Q

At what point is diarrhea considered chronic?

A

30 days

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17
Q

When would you want to work up diarrhea?

A
  1. bloody
  2. hypovolemia
  3. Small volume stool w/ blood/mucus
  4. Immunocompromised/pregnant (listeria)
  5. High fever, duration > 48 hrs
  6. Recent antibiotic use
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18
Q

What can you do to test whether an infectious agent is causing the diarrhea?

A
  1. Fecal WBC
  2. Lactoferrin
  3. Stool culture (salmonella, shigella, campylobacter, EHEC)
  4. Ova and parasite screen for crypto, giardia, amoeba
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19
Q

How does norovirus cause disease?

A

Damages the brush border. Causes NON bloody diarrhea

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20
Q

How is rotavirus released into the body?

A

Activatino by proteolysis releases subviral particles

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21
Q

How do you diagnose norovirus?

A

PCR

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22
Q

How do you diagnose rotavirus?

A

Rapid antigen detection

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23
Q

How do you treat noro/rotavirus?

A

SUPPORTIVE

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24
Q

How does shigella cause disease

A

It invades the colonic epithelial cell and causes ulcerations

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25
Q

What is a serious complication of shigella?

A

Shiga toxin can cause hemolytic anemia

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26
Q

How does s. typhi cause disease

A
  1. Penetrates bowel mucosa
    - ->lymphatics
    - ->bile
    - ->GI
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27
Q

What does S typhi look like, clinically?

A

headache/fever/malaise
Rose spots
T-pulse dissociation
Positive blood cultures

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28
Q

How do you treat s typhi?

A

Ampicillin
Tmp/SMX
Cipro

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29
Q

HOw do you treat a regular salmonella infection?

A

FLUIDS–>if immunocompromised or very severe, then consider cipro/Bactrim

30
Q

What complication does C diff cause?

A

pseudomembranous colitis

31
Q

How do you treat C diff?

A

Metronidazole. Vancomycin if severe

32
Q

What type of organism is yersinia enterocolina?

A

Intracellular.

33
Q

How does yersinia present?

A

Appendicitis-like sx with diarrhea and fever

34
Q

How do you treat yersinia?

A

Tetracycline, TMP, SMX

35
Q

How does vibrio parahemolyticus present?

A
  1. Explosive, watery diarrhea with low grade fever.
    - ->dx thru stool culture
    - ->tx is supportive
36
Q

How does cholera cause disease?

A

Toxin increases adenylate cyclase.

37
Q

How does cholera get diagnosed?

A

rice water stool with NO FEVER

–>use stool culture to diagnose

38
Q

How do you treat cholera?

A

IV/PO fluid replacement

Tetracycline

39
Q

How does listeria cause disease?

A

Intracellular pathogen. Infects macrophages

40
Q

Who is at risk for listeria?

A

Pregnant
Immunocompromised
very young
very old

41
Q

How does listeria present?

A

Fever, myalgias
bacteremia
meningitis

42
Q

How do you diagnose and treat listeria?

A

Dx: blood/CSF
Tx: Ampicillin

43
Q

What are common causes of acute endocarditis?

A

S aureus
S pneumo
GAS

44
Q

What are common causes of subacute endocarditis?

A

Viridans strep

CoNStaph

45
Q

What are the differences between subacute and acute endocarditis?

A

Subacute ONLY occurs on abnormal valves

  • -Onset occurs over months
  • -Caused by less virulent organisms
46
Q

What are the predisposing factors for endocarditis?

A
  1. IV drug use
  2. Mitral valve prolapse
  3. Degenerative valve disease
  4. rheumatic heart disease
  5. Poor dental hygiene
  6. hemodialysis
47
Q

What would you worry about if you saw an S bovis endocarditis?

A

Colon cancer/lesion

48
Q

What kind of endocarditis would you see in men with bladder outlet obstruction?

A

enterococci

49
Q

Suppose you have culture negative endocarditis. What kind of organism do you have? What might you suspect in recent history of pt?

A

Fastidious organism

  • -Caused by recent antibiotic tx
  • -Try growing for a longer period or on a richer medium
50
Q

What are the causes of culture-negative endocarditis?

A

HACEK

  • Hflu
  • actinobacillus (not bacter)
  • cardiobacterium
  • eikenella
  • kingella
51
Q

What is the typical presentation of bacterial endocarditis?

A
Fever
Roth's spots
Osler's nodes
Murmur
Janeway lesions
Anemia
Nail hemorrhage (splinter hemorrhages)
Emboli
52
Q

What is unique about IV drug use endocarditis?

A
  • polymicrobial (S aureus also common)
  • Right sided (tricuspid)
  • Pleuritic chest pain common
  • -Pulmonary emboli rather than cerebrovascular emboli
53
Q

Why would you worry about giving nafcillin?

A

Can cause acute interstitial nephritis

54
Q

What are the indications for valve replacement surgery?

A
  1. Bacteremia that persists beyond 5 days
  2. heart block
  3. CHF
  4. Fungi, pseudomonas,
  5. Recent emboli
  6. Vegetations over 1 cm
55
Q

If infection is < 12 mos after placement of the prosthetic valve, it’s usually caused by:

A

Coagualase negative staph

56
Q

If infection occurs after 12 months after a prosthetic valve is placed, it’s usually caused by:

A

STREP

57
Q

If a patient gets an infection of a prosthetic valve, what would make you think it was hospital acquired?

A

If it occurred within 2 months of surgery

58
Q

Dx of endocarditis?

A

Blood cultures–3 different sites

  • -If SBE: cultures are extracted over hours
  • -If ABE: taken over several minutes

Echocardiography
Duke criteria

59
Q

Describe the differences between a transthoracic and transesophageal echo

A

Transthoracic: rapid, high specificity

  • -Low sensitivity
  • -Body habitus dependent

Transesophageal: MUCH higher sensitivity than a transthoracic echo (duh, you’re closer to the heart!)
–Better image, but more expensive/invasive

60
Q

What are the major duke criteria?

A
  1. New murmur
  2. Blood cultures positive with a typical organism
  3. Echo is positive for mass or abscess
61
Q

What are the minor duke criteria?

A
  1. High predisposition for Endocarditis (IV, history)
  2. Fever
  3. Vascular findings (CHF)
  4. Immuno findings (Osler’s nodes or roth spots)
  5. Positive blood cultures with an atypical organism or not consistently positive
62
Q

What would make you think definite endocarditis with the duke crieria?

A

2 major
1 major + 3 minor
5 minor

63
Q

How do you treat endocarditis?

A

If ABE: Start tx as soon as you’ve obtained the blood cultures

If SBE: Delay tx until culture results have returned

Treat until pt has become afebrile and there have been negative repeat blood cultures

64
Q

If HACEK organism: what do you treat with?

A

Ceftriaxone for 4 weeks

65
Q

If Enterococcus, what do you treat with?

A

Penicillin + gentamicin

66
Q

If Strep pneumo, what do you treat with?

A

Gentamicin for 2 weeks, then penicillin for 4

67
Q

If viridans strep, what do you treat with?

A

Penicillin G

68
Q

How do you treat if a patient has a prosthetic valve?

A

Gentamicin for 2 weeks if sensitive strep. Treat for 4-6 weeks of gentamicin if resistant strep

Add rifampin for MSSA, MRSA< and coag - staph IN ADDITION TO THE GENTAMICIN regimen

69
Q

Who should you give Abx prophylaxis to? In what scenarios?

A
  1. pts with underlying valve dz
  2. procedures with a high risk of bacteremia

–Dental procedures and surgery

70
Q

Who are the highest risk pts with endocarditis?

A
  1. Pt with a history of endocarditis
  2. Prosthetic valves
  3. Cyanotic congenital heart disease
71
Q

Who are moderate risk pts with endocarditis?

A
  1. Cardiac malformations
  2. Valvular dysfunction
  3. Hypertrophic cardiomyopathy
  4. Mitral valve prolapse with regurgitation