C.diff - Clostridioides Difficile Infection (CDI) - Diagnosis and Management - GrepMed Handbook



Clinical Presentation + Progression: 

 • Asymptomatic Colonization (~20% of hospitalized pts on ABx)

   → Acute Diarrhea (>3 BM/d) ± blood/mucus, Abd pain, Fever, ↑WBC

   → Pseudomembranous colitis (wall thickening)

   → Fulminant Colitis (Ileus, Toxic Megacolon, Shock, Perforation)



Pathophysiology: Spore ingestion → colonic colonization → proliferation (Abx or chemo) → toxin A/B release → mucosal inflammation and necrosis → pseudomembranes and toxic megacolon

Epidemiology: 

 • #1 nosocomial infection up to 10w post-ABx, but can be community-acquired w/o ABx (esp elderly,  immunocompromised, IBD)

 • ↑Risk: clindamycin, quinolones, cephalosporins, carbapenems.   Lowest Risk: Tetracyclines



Diagnosis:

 • Stool toxin immunoassay (↑Spec) - Toxin A/B

 • GDH - Glutamate Dehydrogenase (↑Sens) - produced by all strains, including non-toxigenic

 • Stool PCR (↑Sens, false ⊕ in colonization, non-toxigenic) - often ordered in reflex if immunoassay equivocal

 • CT A/P: Assess complications (megacolon, perforation). 

 • KUB ↓↓Sens for complications.

 • Flex-Sig: If diagnostic uncertainty (Bx) or no improvement with Tx

Management (IDSA 2021):

 • Note: Fidaxomicin is now preferred over vancomycin (limited by $)

 • d/c offending ABx if possible - otherwise continue Tx for 7d post-Abx

 • Initial CDI Episode:

    - Preferred: Fidaxomicin 200 mg PO bid x 10d

    - Alternative: Vancomycin 125 mg PO qid x 10d

 • 1st CDI Recurrence

 • ≥ 2nd CDI Recurrence 

 • Fulminant CDI (Ileus, Megacolon, Shock, Perforation)

 • Bezlotoxumab 10 mg/kg IV x 1 - Adjunct Tx given along with above regimens for recurrent CDI

 • Fecal Microbiota Transplant (FMT) - consider if 2 recurrences despite appropriate treatment

 • Prophylaxis: Vancomycin 125 mg PO qd - If needing ABx or h/o recurrent/severe CDI



IDSA 2021 CDI Treatment Guideline: https://doi.org/10.1093/cid/ciab549



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