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Infectious Disease > GI Disease > Flashcards

GI Disease Flashcards

1
Q

Moderate inoculum size to cause diarrhea?

A

Giardia
Cryptosporidium
Shiga toxin
Salmonella

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2
Q

Low rate of spread in diarrhea?

A

Campylobacter
Enteroinvasive E. coli
Enterotoxigenic E. Coli
Vibrio cholerae

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3
Q

Norovirus

A

Endemic in nursing homes and cruise ships
Rapid onset
Nausea, vomiting, fever and 3-5 d of diarrhea

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4
Q

Enterotoxigenic e. Coli

A

Virulence: fimbriae, heat labile and heat stable endotoxins

Tx: bactrim or FQ

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5
Q

Enterohemorrhagic E. Coli (EHEC)

Aw Heck….shiga what?

A

E. coli 0157 (Shiga toxin producing
Sorbitol negative)

Non 0157 ( sorbitol positive)

Can cause HUS (hemolytic anemia, thrombocytopenia, renal failure) in 10% of pts

Tx: none
FQ enhance toxin production
If necessary –> azithro

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6
Q

Which Ecoli caused outbreak in 2011 in Germany and France?

A

Enteroaggregative E. coli with shiga toxin from sprouts

26% developed HUS

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7
Q

Organisms that cause diarrhea with smallest inoculum (most contagious)?

A

Shigella

Norovirus

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8
Q

Vibrio cholerae

A

Curved Gram negative bacillus with a flagellum
Profuse watery diarrhea
Tx: fluids, electrolytes

Abx: cipro, tetracycline, doxycycline, azithro (decrease diarrhea duration and volume)

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9
Q

Vibrio vulnificus/parahaemolyticus

A

Causes enteritis, Ssti w/ sepsis after contact with sea water or ingestion of raw seafood
Fulminant infxn in cirrhotic pts
Tx: doxycycline AND ceftazidime/cipro

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10
Q

Toxigenic vs invasive diarrhea

A

Toxigenic: occurs in hrs
Upper GI sx: watery diarrhea, no fecal WBC,
Vibrio, etec, b. Cereus, staph aureus, clostridium perfringens
———————————————
Invasive: 1-3 d
Abd pain, fever, fecal WBC, inflammatory diarrhea
Shigella, campylobacter, salmonella, EHEC, yersinia, v. Parahaemolyticus

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11
Q

Shigella diarrhea

A

High rate of spread with low inoculum
Dysentery (bloody diarrhea)
Reactive arthritis, iritis, persistent illness
RF: daycare, MSM

Dx: EIA for shiga toxin in stool, stool cx

Tx: yes! With cipro or bactrim To decrease shedding

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12
Q

Salmonella (non typhoid)

Non lactose fermenter

A

95% infxns from food (associated with peanut butter) reptiles, amphibians

8% healthy pts develop bacteremia
50% high risk pts develop bacteremia (sickle cell pts at risk for osteo)

Sx: rose spots, HSM, enteric fever, can colonize GB, can have ileal perforation from necrotic peyers patches

If resistant to nalidixic acid, then resistant to FQ

Tx: none,
If IC, 65 yrs:
cipro/azithro, ceftriaxone x 7-14d

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13
Q

Campylobacter jejuni

A

80% infxns from food
Hx of contact with poultry puppies

Sx: Prodrome of fever and h/a,
Complications: GBS (asc weakness), IBS, reactive arthritis

Tx: erythromycin

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14
Q

Salmonella, shigella, and campylobacter in Asia, India

A

Incr FQ resistance, treat with azithromycin instead

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15
Q

Giardia

A

“Cross eyed” flagellated Protozoa
RF: beavers, stream water, day care

Dx: rapid ag test, stool pcr
Tx: tinidazole, flagyl, Nitazoxanide

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16
Q

Cryptosporidium

A

Animal and human reservoirs
RF: waterparks, pools, daycare, wells

Tx: Nitazoxanide

17
Q

Cyclospora

A

Nepal, Haiti, Peru, Guatemalan raspberries, snow peas

Often o&p is negative, seen on modified acid fast stain

Tx: bactrim x 7d

18
Q

Paralytic shellfish

A

Toxin from dinoflagellates in water taken in by mollusks like clams and mussels

Sx: onset in minutes to hours, facial paresthesia and paralysis, mouth numbness, LE weakness

19
Q

Ciguatera

A

Toxin from dinoflagellates in large fish or eel (grouper, snapper, barracuda, amberjack, parrotfish), tastes peppery or pungent

Sx: mixed Neuro and GI sx (decreased BP x 2-3 wks, decreased heart rate, blurred vision, lip numbness, teeth pain, loose teeth, metallic taste in mouth, tingling extremities, temperature dyesthesia, heart block, vomiting, resp failure)
Sx worse with caffeine and alcohol

** freezing or cooking has no effect on killing toxin

20
Q

Neurotoxin inhalation

A

Toxin inhaled during algal blooms (red tide)

Mild illness, short lasting

21
Q

Tetrodotoxin

A

Toxin in pufferfish, can be fatal

Sx: within hours, weakness, dizziness, headache, paresthesia, hypotension, resp failure

Tx: supportive

22
Q

Scombroid

A

Histamine like reaction
Food tastes peppery, salty, bubbly (spoiled fish at room temp)

To prevent, refrigerate from catch to cooking

Gram negative produce histamine like substance –> hives, wheezing, headache, dizziness, urticaria, diarrhea, vomiting, mouth burning, flushing

*Resolves in 10-12 hours with antihistamines

23
Q

Diarrhea that occurs 2-7 hrs after a meal?

A

Preformed toxin -

  1. ) staph aureus (presents with nausea and vomiting)
  2. ) or bacillus cereus
24
Q

Diarrhea with an 8-14 hr incubation?

A

Clostridium perfringens

Watery diarrhea

25
Q

Diarrhea that has a 24-48 hr incubation?

A

Norovirus
E.coli
Listeria

26
Q

21 yo student with vomiting, fever, bloody diarrhea few hrs after eating?

A

Not food from the restaurant,

Fever and bloody BMs take time to develop

Preformed toxin usually presents with just vomiting

27
Q

Norovirus

A

24-48 hr incubation
90% cases with vomiting
50% with diarrhea
30% with fever

Usually recover in 12-60 hrs
Supportive care, bismuth

*clean with a chlorine bleach 1:50-1:10 dilution

28
Q

Nursing home resident with diarrhea?

A

Treat with abx to decrease risk of complications

29
Q

Which organism can cause abx associated hemorrhagic colitis

A

Klebsiella oxytoca due to cytotoxic

Also hypermucoid colonies, + string test

Can cause liver abscess and meningitis

30
Q

Helicobacter pylori

A

GNR, spiral shaped, flagellated, catalase +, oxidase+, urease +

Transmitted person to person or mother to child

Associated with gastritis, duodenal ulcer, gastric ulcer, MALT lymphoma, gastric cancer

Testing: d/c ppi x2 weeks, d/c abx x 4 wks, (if GI bleed, wait 4-8 wks before testing) and then get stool antigen, or urea breath test,
Serology is less sensitive and specific
If alarm sx: EGD with biopsies

31
Q

H.pylori tx?

A
  1. ) PPI + clarithromycin 500mg twice daily + amoxicillin 1gm twice daily x 10-14 d
  2. ) quad tx: ppi+ bismuth+ metro+ tetracycline
  3. ) If ß-lactam allergy: PPI + clarithromycin 500mg twice daily + metronidazole 500mg twice daily.

TEST OF CURE 4 wks post tx with stool ag test or urea breath test

** flagyl resistance 37%, clarithro resistance 11%, amox and tetracycline resistance is rare

32
Q

HIV pts with h. Pylori infxn

A

Quad tx
Dose adjust Clarithromycin if pt on ritonavir or cobicistat

Can’t use atazanavir/r with Omeprazole, typically switch art

33
Q

Clostridium dificile - which abx are high risk?

A

Diarrhea with either + stool test or cscy with pseudo membranous colitis

Most commonly with clindamycin, 3rd generation cephalosporins (e.g., ceftriaxone, cefotaxime), fluoroquinolones (e.g., ciprofloxacin, levofloxacin, moxifloxacin)
» Medium: amoxicillin/clavulanate, other ß-lactams or ß-lactam/ß-lactamase inhibitor combinations, carbapenems (e.g., imipenem)
» Low or minimal risk: metronidazole, vancomycin (IV), aminoglycosides, nitrifurantoin, methenamine, fosfomycin, sulfonamides, tetracyclines.

34
Q

C dificile infection control

A

Gloves, gowns, wash hands with soap and water
Private rooms

Post - clean room with chlorine containing sporicidal agent

35
Q

C dificile

A

Sx: no fever, leukocytosis,
Hyper virulent strain with binary toxin - increased toxin A and B production, mutation in tcdc gene

Dx: 1 diarrheal stool (unless ileus is suspected) for pcr/naat for toxin A and B
• Complications: ileus and toxic megacolon, hypoalbuminemia, shock, renal failure, leukemoid reaction.

Tx:
• Mild or moderate: patients with WBC 15, 000 or creatinine >1.5 x baseline.
» Vancomycin 125 mg PO four times daily x 10-14 d.
• Severe infection and complicated: hypotension, ileus, toxic megacolon; concern regarding whether oral drug reaches large bowel.
» Vancomycin 500 mg four times daily PO or by NG tube plus metronidazole 500 mg IV q8h.
» If complete ileus, also administer vancomycin 500mg q6h per rectal retention enema if feasible.

36
Q

C dificile recurrence

A

• Relapse CDI: 20-25% of cases after initial course of therap.
» First relapse: treat as above.
» Second or more relapses:
No more flagyl due to neurotoxicity

vancomycin 125 mg PO four times daily x 10-14 days and then “taper and pulse” with 125 mg PO twice daily x 7 days then 125 mg every other day x 6 weeks.
* rifaximin after last course of vanco with some success

37
Q

Probiotics to prevent c. Dificile?

A

No per IDSA

Infectious Disease (7 decks)

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