C.diff

C.diff epidemiology

-Causes more deaths than all other intestinal infections combined -Most frequent cause of diarrhea acquired in hospital setting

Relapse of C.diff

-Defined as 2nd episode occurring within <8wks of index case -Almost all 2nd episodes due to original infecting strain (~90%)

Reinfection of C.diff

-Defined as a 2nd new episode occurring ≥8 wks after index case -Initially felt to represent a "new" infecting strain

test of cure with C.diff

-Don't perform "test of cure" assays → results may be misleading → 30% of successfully treated pts have (+) assays -Pts who recover from CDI can become carriers & shedders of C. difficile spores *also* don't give vanco with cholestyramine (it binds it up)

Clinical Manifestations of c.diff

-Fever & anorexia common -Diarrhea → Fecal incontinence common -Abdominal cramping

Treatment of Relapsing C.diff

-If relapse occurs, repeat same course of ABX once -after 1 replase refer to ID or GI - Fecal Microbiota Transplantation (FMT), immunotherapy

C.diff dx

-Important to limit CDI testing to pts with clinically significant diarrhea (CSD), b/c asymptomatic colonization with C. difficile reported -Follow "Brecher guidelines" for stool collection / testing (minimizes false (+) tests) -NAAT (PCR)

C.diff common lab findings

-Leukocytosis (may be very high 15,000-85,000) -Hypoalbuminemia (reflecting a protein-losing enteropathy) common

C.diff tx mild-moderate? moderate severe?

-Mild-Moderate Disease → Metronidazole PO (IV if ileus) x 10x14 days -Moderate-Severe Disease → Vancomycin PO (IV no good) x 10x14 days -colectomy if extensive pseudomembranes

Pathogenesis of C.diff

-Pathogenic strains of C. difficile produce an enterotoxin (toxin A) & a cytotoxin (toxin B) → colonic inflammation -emergence of more toxic epidemic strain (BI/NAP1), felt to be from widespread use of FQs -- 17 times more toxins pumped out then it used to

Community-Acquired C.diff

-Symptom onset occurs in community or within 48hrs of admission to a hospital, after no hospitalization in the past 12 wks -Peripartum women & children are at increased risk

C. diff microbiology

-an anaerobic gram-positive, spore-forming (resistant to heat & desiccation), toxin-producing bacillus -Phenotypic characteristics include a "horse stable" odor caused by p-cresol production

Risk Factors for Complications or Mortality after getting C.diff

1) Age (≥80 yrs) 2) Admission for CDI 3) Acid suppression (PPIs, H2RAs) 4) Corticosteroid use >5mg/d

C.diff risk factors for colonization and disease

1) Age >65 yrs 2) Usually elderly, frail hospitalized / NH pts 3) Comorbid conditions (organ transplant & CRF mostly) 4) dysbiosis (microbial imbalance) 5) Widespread use of H2RAs & PPIs 6) Length of HCF stay (increased risk >1wk)

Spectrum of c.diff (6)

1) Asymptomatic infection / colonization 2) Diarrhea without colitis 3) Nonpseudomembraneous colitis with or without diarrhea 4) Pseudomembraneous colitis (PMC) 5) Toxic megacolon 6) Fulminant colitis

moderate-severe c.diff disease is defined as any one of the 4 following:

1) pseudomembranous colitis (PMC) 2) marked peripheral leukocytosis (>15,000-20,000) 3) acute renal failure 4) hypotension dis where you use vanco 125-250mg PO q6h x 10-14d

Clinically significant diarrhea to test for c.diff is defined as

3 or more unformed stool samples within 24 hours in pt who also have risk factors for c. diff

Health Care-Associated C.diff

Hospital-acquired CDI if onset of symptoms occurs >48hrs after admission to or <4wks after d/c from a health care facility

Abdominal series findings with C.diff

Look for dilated loops of bowel → concern when close to 10cm -CT may show diffuse colonic thickening -Colonoscopy shows pseudomembranes

Cholestyramine + vancomycin

Cholestyramine resin binds vancomycin → don't combine-