Surgical Pathology Criteria

Pseudomembranous Colitis

Differential Diagnosis

Chemical / Iatrogenic Colitis Antibiotic-associated Pseudomembranous Colitis
Diffuse necrosis and sloughing of superficial mucosa Frequently patchy involvement of 2-10 crypts with normal surrounding crypts
Mucosal microthrombi and hemorrhage Not associated with microthrombi or hemorrhage
History of endoscopy or introduction of foreign substance History of antibiotic therapy
Both may form a pseudomembrane

 

Pseudomembranous Colitis Enterohemorrhagic E coli Colitis
Endoscopic pseudomembrane Pseudomembrane only microscopic
Necrotic crypt epithelium erupts into lumen to form pseudomembrane Entire upper mucosal layer may slough into lumen to form pseudomembrane
Hemorrhage is not prominent Prominent hemorrhage and capillary thrombosis
C difficile titers elevated E coli O157:H7 identified by culture
Associated with antibiotic therapy Not associated with antibiotic therapy

 

Pseudomembranous Colitis Ischemic Colitis
Diffuse Localized, may form a mass
No hyanization of lamina propria Hyalinized lamina propria
Occasional atrophic crypts Atrophic microcrypts common
Usually only superficial necrosis Necrosis frequently transmural
C difficile titer elevated C difficile titer negative
Associated with antibiotic therapy Not associated with antibiotic therapy

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