Acute Ischemic Bowel

Common sites:

• small bowel (SMA territory)

Gross features:

• transmural infarction:
• early stages – serosa and mucosa intensely congested and dusky to purple-red
• with time – wall is edematous, thickened, rubbery, and hemorrhagic\
• sanguinous mucous or frank blood in lumen
• in arterial infarction – sharply defined border between infarcted and normal bowel
• in venous infarction – gradual border
• may have perforation
• mucosal and mural infarction:
• serosa looks normal
• mucosa of affected areas is dark red/purple, hemorrhagic, edematous, thickened
• may have superficial ulceration

Histologic features:

• transmural infarction:
• obvious edema
• hemorrhage starting at mucosa
• sloughing necrosis of the mucosa
• indistinct mural muscular features (nuclei)
• mucosal and mural infarction:
• mildest form:
• necrotic or sloughed tips of villi or superficial epithelium of colon
• no inflammation
• mild vascular dilation
• intermediate form:
• sloughing leaves only lamina propria
• severe form:
• extensive hemorrhage and necrosis of multiple tissue layers
• secondary acute and chronic inflammation along the viable margins underlying and adjacent
• may have bacterial superinfection, mimicking nonvascular enterocolitis