Intestinal angioedema

Intestinal angioedema, also known as bowel angioedema, is edema into the submucosal space of the bowel wall following protein extravasation from "leaky" vessels. It can affect both the small and large bowel.

Clinical presentation

Patients often present with non-specific findings of abdominal pain, nausea, and vomiting.

Complications

• hypovolemic shock: fluid loss into the bowel wall, lumen and peritoneum may be massive ⁶

Pathology

There are three main types of intestinal angioedema:

• hereditary deficiency of C1-inhibitor enzyme

• acquired deficiency of C1-inhibitor enzyme (associated with B-cell lymphoproliferative disorders and autoimmune disease)

• medications

  • angiotensin-converting enzyme inhibitors (ACEi) ^3​

    • especially enalapril and lisinopril 

  • angiotensin II receptor blockers

  • calcium channel blockers ⁴

The exact mechanism of angioedema in the bowel is not completely understood, but it is thought to involve bradykinin pathways and subsequent vasodilation (instead of histamine pathways) during acute periods.

Radiographic features

CT

• bowel changes

  • long segment concentric thickening of the bowel submucosa

    • jejunum more often affected

  • mural stratification

  • straightening of bowel loops

  • no obstruction

• mild mesenteric edema

• ascites

• no lymphadenopathy

Treatment and prognosis

In cases of medication-induced angioedema, removal of the offending agent usually results in complete resolution.

Differential diagnosis

• ischemic bowel

  • lack of bowel wall enhancement

  • possible pneumatosis

• bowel wall intramural hemorrhage: look for history of anticoagulation

• inflammatory bowel disease (e.g. Crohn disease)

• lymphoma: usually more irregular

• graft vs host disease: look for history of transplant and immunosuppression

• radiation enteritis

• infectious enteritis