Flashcards in diarrhea presenting with fever Deck (29):
high carriage in??
G+, anaerobic spore-former
NF in 3% gen pop
20-40% carriage in nursing home/hosp. pts
C. diff ribotype 078/ST 11 (clade 5)
animal and food assoc-->sev. CDI
C. diff toxinotype III strain NAP1/BI/027
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)
C. diff produces 2 toxins
Toxin A and Toxin B (homology btw them)
both cause cytopathic effect by modifying proteins that regulate *actin* formation via glycosylation of Rho proteins
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*
C. diff incidence: increasing?
yes by 26%/yr
nosocomial C. diff usually trigger by ??
who is at risk more ??
abx therapy (new strains related to inc. FQ use)
C. diff reservoir
calves, pigs, 3% of humans (more in hosp pts/nursing home)
C. diff age/gender/season assoc.
old age (HCA-CDI)
young adults (CA-CDI)
No gender or season assoc.
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
other C. diff risk factors
antineoplastic agents, cathartics, stool softeners, enemas, IBD, antacids, HIV
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
C. diff cardinal symptom
febrile watery diarrhea, 10-15 stools/day!
lower abd. cramps, no cyst. symptoms
C. diff causes loss of ?? in stool
serum proteins-->hypoalbuminemia, edema, ascites
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
?? may proceed C. diff diarrhea
sev. CDI abd. pain caused by
ileus, colonic dilation, toxi megacolon **(get a consult)
classic pseudomembronous colitis described as ?? over ??
what is pathognomonic for CDI??
elev. yellow plaques over inflamed mucosa
even more pronounced than sev. colitis
C. diff complications
bradycardia, hypotnsn, shock, megacolon, colonic perf
C. diff dx: suspect when ??
abx in prev. 2 mos or diarrhea began 72 hr + after hospitalization
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
C. diff dx for special occasions, rapid dx
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
C. diff ddx
UC, chronic IBD, Crohn's
C. diff tx
stop abx that cause it
C. diff tx: abx?
vancomycin (cell wall inhib, for sev. disease/metro resistance)
fidaxomicin (macrolide, prot. syn inhib, less effect on NF than vanco)
avoid ?? while tx C. diff
antiperistaltic agents (loperamide)
may hide symptoms and induce toxic megacolon
C. diff pts: how many will relapse?