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Flashcards in Diarrhea Deck (45)
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1
Q

What are the two preferred drugs for treatment of Campylobacter jejuni?

A
  • Quinolones (Ciprofloxacin)
    • Inhibits DNA gyrase and/or topoisomerase IV
  • Azithromycin, erythromycin
    • Binds 50S ribosomal subunit, blocking mRNA translocation
2
Q

What are some potential alternatives for treatment of Campylobacter?

A
  • Gentamicin
  • Carbapenem
  • Tetracycline
3
Q

Among the macrolides, what differences might provide an advantage for azithromycin vs. erythromycin?

A
  • Erythromycin
    • Pro-kinetic agent
    • Risk for arrhythmias, cardiac arrest
    • Drug interactions, CYP3A inhibitor
    • More frequent dosing
  • Azithromycin
    • Lower incidence of GI effects
    • Lower incidence of cardiac effects
    • Few drug interactions
    • Less frequent dosing
4
Q

Salmonella (non-typhi) & Shigella

What are the basic properties of these bugs?

What are the implications for drug resistance?

A
  • Gram-negative rods
  • Facultative anaerobes
  • Members of the Enterobacteriaceae family
  • ß-lactamase (often transmissable) has become quite common in this family
5
Q

What are the approved drugs for Shigella & Salmonella?

A
  • Ampicillin (both)
  • TMP/SMX (Shigella)
  • Ciprofloxacin (both)
6
Q

What are the drugs used for Shigella & Salmonella?

A
  • Ciprofloxacin
  • Ceftriaxone
  • Azithromycin
7
Q

Why does prophylactic antibiotic therapy increase the risk for contracting Salmonella & other enteric infections?

A

It suppresses the normal flora

  • GI normal flora is an important barrier to infection with enteric pathogens including Salmonella
8
Q

What drugs are FDA-approved for C. difficile?

A
  • Vancomycin
  • Fidaxomicin
9
Q

________ is a common accepted therapy for C. difficile, but is not formally FDA-approved for this use.

A

Metronidazole

10
Q

Mutations in RNA polymerase ß (rpoB) could result in decreased sensitivity to ________.

A

Fidaxomicin

  • Macrocyclic that blocks formation of RNA polymerase open promoter complex
11
Q

Describe Metronidazole resistance in C. difficile

A
  • Often transient
  • Lost in storage
  • After freeze/thaw
12
Q

Which drug for C. difficile has the narrowest spectrum of antibiotic activity?

A

Fidaxomicin

  • Primarily Clostridium only
  • Some effects on Peptostreptococcus
  • No effects on other gram positives or negatives
13
Q

What are the possible contributors to lower recurrence of C. difficile with fidaxomicin than vancomycin?

A
  • Less disruption of normal flora
  • cidal (time-dependent) vs. static effect of vancomycin on C. difficile
  • Fidaxomycin has an active metabolite OP-1118
  • Fidaxomycin has post-antibiotic effect (6-10 hr)
14
Q

When using oral vancomycin for treating C. difficile, which drug side effects would you expect?

A

Nausea, abdominal pain

  • Oral vancomycin is very poorly absorbed
  • Maintains high colonic concentrations
  • Less likely to get systemic side effects (red man, ototoxicity, nephrotoxicity) w/ oral dosing
  • IV - phlebitis
15
Q

For patients unable to take oral drugs, what can be given IV for treating C. difficile?

A

Metronidazole

*IV vancomycin has no effect on C. diff enterocolitis

16
Q

C. difficile spores germinate in the ____________ upon exposure to bile acids.

_________ facilitate C. difficile movement

C. difficile multiplies in the _____

A

small bowel

flagellae

colon

17
Q

The most common cause of infectious diarrhea in children is _______.

A

Viral

18
Q

True/False

Gatorade is adequate for severely ill patients

A

FALSE

  • WHO recommends
    • 3.5 g NaCl
    • 2.9 g trisodium citrate or 2.5 g Na2CO3
    • 1.5 g KCl
    • 20 g glucose or 40 g sucrose
    • 1 L of water
19
Q

Constipation is a very common problem with _____ use.

A

opioid

20
Q

afebrile

fluid overload

scleral icterus

petechial rash on LE

bilateral LE edema to ankle

E. coli O157:H7

A

Hemolytic Uremic Syndrome

21
Q

Hemolytic Uremic Syndomre after antibiotics

A

Enterohemorrhagic E. coli (O157/H7)

22
Q

Traveler’s diarrhea & post-infectious IBS

A

Enterotoxigenic E. coli

23
Q

Guillain Barre Syndrome

Crohn’s Mimic

Pseudoappendicitis

A

Campylobacter

24
Q

Pet turtles

Osteomyelitis in sickle cell/asplenic patients

A

Salmonella

25
Q

Day care/institutions

HUS, but less common

Seizures

Reactive arthritis

A

Shigella

(S. dysenteriae for HUS)

26
Q

Shellfish contamination

A

Vibrio cholerae

27
Q

Most common cause of C. difficile worldwide

Cruise ships

A

Norovirus

28
Q

Most common pediatric cause of C. difficile

A

Rotavirus

29
Q

When should you order a stool culture?

A
  • Severly ill
  • Outbreaks
  • Require hospitalization
  • Immunocompromised patients (HIV)
  • Patients w/ co-morbidities (IBD)
  • Some employees, such as food handlers or daycare providers, may require negative stool cultures to return to work
30
Q

What empiric antibiotics are used to treat Traveler’s Diarrhea?

A
  • Moderate-severe
  • Fluoroquinolone or TMP-SMX
31
Q

What are the indications for empiric antibiotics?

A
  • >8 stools/day
  • Volume depletion
  • Symptoms >1 wk
  • Hospitalize patients
  • Immunocompromised hosts
32
Q

When should anti-motility agents be used?

What are some examples?

A
  • ONLY if fever is absent & stools not bloody
    • Bacterial translocation
    • C. diff –> toxic megacolon
  • Loperamide or diphenoxylate
33
Q

What is osmotic diarrhea?

A
  • Neither the small intestine nor the colon can maintain an osmotic gradient
  • Unabsorbed ions remain in the lumen
    • Retain water
    • Maintain intraluminal osmolality (290 mOsm/kg)
34
Q

What can cause osmotic diarrhea?

A
  • Ingestion of poorly absorbed ions or sugars or sugar alcohols
    • Mannitol, sorbitol
    • Magnesium, sulfate, phosphate
  • Disaccharidase deficiency will prevent absorption (lactose intolerance)
35
Q

How does osmotic diarrhea present clinically compared to secretory diarrhea?

A
  • Osmotic diarrhea disappears with fasting or cessation of the offending substance
  • Electrolye absorption is not impaired in osmotic diarrhea
36
Q

What are the causes of secretory diarrhea?

What is the most common cause?

A
  • Either net secretion of anions (Cl or H2CO3) or inhibition of net Na absorption
  • The most common cause is infection
  • Enterotoxins
    • Interact w/ receptors & modulate intestinal transport
    • Block specific absorptive pathways, in addition to stimulating secretion
    • Inhibit Na/H exchange in the small intestine & colon
  • Peptides produced by endocrine tumors
37
Q

What is the osmotic gap?

A

Osmotic gap = serum Osm - Est stool Osm

2 x (Na + K) ~ 290 mmol/L

small osmotic gap <50

gap >100 indicates osmotic diarrhea

38
Q

What is the clinical presentation of “classic Celiac Disease”?

A

Diarrhea, bloating, abdominal pain & weight loss

39
Q

“Atypical” Celiac Sprue

A
  • Iron Deficiency
  • Osteoporosis
  • Dermatitis Herpetiformis
  • IBS
  • DM type 1
  • Elevated LFTs
40
Q

Where is folate absorbed?

Where are the fat-soluble vitamins absorbed?

Where is vitamin B12 absorbed?

A
  • Folate & DAKE
    • Duodenum & jejunum
  • Vitamin B12
    • Ileum
41
Q

What is the non-GI presentation of Celiac Disease?

A
  • Unexplained iron-deficiency anemia
  • Folic acid or VitB12 deficiency
  • Reduced serum albumin
  • Unexplained elevated LFTs
  • Other autoimmune disorders
    • Type 1 DM
    • Thyroid disfunction
    • Addison disease
    • Primary Biliary Cirrhosis
    • Sjogren’s disease
    • Autoimmune hepatitis
  • Down syndrome & Turner syndrome
  • Selective IgA deficiency
42
Q

All newly diagnosed Celiac Disease patients should have a __________.

A

bone density

43
Q

What are the malignant complications of Celiac Disease?

A
  • Enteropathy Associated T-cell Lymphoma
    • High-grade T-cell NHL
    • 5 yr survival ~10%
    • 20X more in CD
  • Risk normal on GFD
44
Q

What is the most clinically useful serology for CD?

What is seen on small intestinal biopsy?

A
  • IgA Tissue Transglutaminase (tTG)
  • “scalloping” or “notching” of the folds
  • Small intestinal villous atrophy, intraepithelial lymphocytosis & crypt hyperplasia
45
Q

What does a gluten free diet consists of?

A

Avoid all foods containing wheat, rye & barley gluten

Avoid malt