diarrhea presenting with fever Flashcards Preview

Micro > diarrhea presenting with fever > Flashcards

Flashcards in diarrhea presenting with fever Deck (29):
1

Clostritium difficile
NF?
high carriage in??

G+, anaerobic spore-former
NF in 3% gen pop
20-40% carriage in nursing home/hosp. pts

2

C. diff ribotype 078/ST 11 (clade 5)

animal and food assoc-->sev. CDI

3

C. diff toxinotype III strain NAP1/BI/027
virulence??

via what genetic alteration??
associated with ???

hypervirulent strain, CA-CDI
produces 16x more toxin A and 20x more toxin B in vitro than other strains via...
deletion of tcdC gene (depressor of toxin prod.)
use of FQs (FQ resistant)

4

C. diff produces 2 toxins
mechanism??

Toxin A and Toxin B (homology btw them)
both cause cytopathic effect by modifying proteins that regulate *actin* formation via glycosylation of Rho proteins

5

in response to C. diff toxins: neurons release ?? and LP immune cells releases ??

neurons release substance P
immune cells of LP (i.e. MALT) release inflamm. mediators:
*histamine, TNF-a, IL-1*

6

C. diff incidence: increasing?

yes by 26%/yr

7

nosocomial C. diff usually trigger by ??
who is at risk more ??

abx therapy (new strains related to inc. FQ use)
oldies >60

8

C. diff reservoir

calves, pigs, 3% of humans (more in hosp pts/nursing home)

9

C. diff age/gender/season assoc.

old age (HCA-CDI)
young adults (CA-CDI)
No gender or season assoc.

10

3 major C. diff risk factors

abx: weeks after tx (takes 3 mos to return to baseline risk)

*hospitalization*: inc. asymptomatic carriage in hosp/nursing home pts

Community-acquired: use of PPIs and H2 blocker use

11

other C. diff risk factors

antineoplastic agents, cathartics, stool softeners, enemas, IBD, antacids, HIV

12

C. diff pathogenesis: abx suppress NF, allowing (previously eaten, colonized) C. diff OG and toxin production
the cytotoxin produces a ??

pseudomembrane: fibrin mesh made of necrotic cells, PMNs, monocytes and RBCs
"white plaque" appearance

13

C. diff cardinal symptom
others

febrile watery diarrhea, 10-15 stools/day!
lower abd. cramps, no cyst. symptoms

14

C. diff causes loss of ?? in stool

serum proteins-->hypoalbuminemia, edema, ascites

15

indicators of severed CDI
do what w. these pts ??
even more worrisome, req. prompt sx consult

fever >38, abd. distension, leukocytosis (>15-20,000)
admit to ICU, sx consult
leuks as high as 50,000 and lactic acidosis

16

?? may proceed C. diff diarrhea

leukocytosis

17

sev. CDI abd. pain caused by

ileus, colonic dilation, toxi megacolon **(get a consult)

18

classic pseudomembronous colitis described as ?? over ??


symptoms??

what is pathognomonic for CDI??

elev. yellow plaques over inflamed mucosa


even more pronounced than sev. colitis

endoscopic appearance

19

C. diff complications

bradycardia, hypotnsn, shock, megacolon, colonic perf

20

C. diff dx: suspect when ??

abx in prev. 2 mos or diarrhea began 72 hr + after hospitalization

21

C. diff dx

stool Cx (sn) (G+ rods with subterminal spores and leukos)
cytotoxin assay (sp) - do both!
EIA and latex agglutination: test for toxin A and B

22

C. diff dx for special occasions, rapid dx

endoscopy

23

in CA-CDI ppl who require hospitalization..

screen for C. diff toxins w. PCR:
tcdA and tcdB (and tcdC: regulatory) -sn and sp!
better than EIA

24

C. diff ddx

UC, chronic IBD, Crohn's

25

C. diff tx

stop abx that cause it
fluid/e-lyte replacement
abx
probiotic/fecal transplant

26

C. diff tx: abx?

metronidazole (FLD)
vancomycin (cell wall inhib, for sev. disease/metro resistance)
fidaxomicin (macrolide, prot. syn inhib, less effect on NF than vanco)

27

avoid ?? while tx C. diff
why??

antiperistaltic agents (loperamide)
may hide symptoms and induce toxic megacolon

28

C. diff pts: how many will relapse?

20%

29

C. diff prev.

barrier precautions
isolation
clean with sporicidal agents
wash hands w. soap and water
restrict abx use, esp: 2nd, 3rd gen cephs, clindamycin, FQs (or combo of the 3)
probiotics: Lactobacillus and Saccharomyces boulardii
wash bathroom with bleach

Decks in Micro Class (61):