ACE Inhibitor-Induced Angioedema

ACE inhibitors rarely (0.2% of patients) cause peripheral angioedema. Visceral angioedema is even less common. For unknown reasons, the vast majority of the cases reported in the literature have been women. Patients may present with an acute abdomen with abdominal pain, vomiting and watery diarrhea. Symptoms are associated with the onset of ACE inhibitor therapy and resolve quickly following discontinuation of the offending medication.

CT findings are nonspecific and consist of circumferential small bowel wall thickening, which may be segmental, as well as mucosal enhancement with prominence of the mesenteric vessels. The low-attenuation submucosa stands out against the enhancement of the thickened mucosa. Ascites is also seen.

Differential considerations of CT findings include:

• Ischemia
• Henoch–Schönlein purpura
• Intramural hemorrhage
• C1-esterase inhibitor deficiency: May be congenital (hereditary/inherited angioedema) or acquired as part of a paraneoplastic syndrome
• Contrast reaction

References

• Fisher AJ, Fleishman MJ, Hancock D. Angioedema of the small bowel: CT appearance. AJR Am J Roentgenol. 2000 Aug;175(2):554.
• Marmery H, Mirvis SE. Angiotensin-converting enzyme inhibitor-induced visceral angioedema. Clin Radiol. 2006 Nov;61(11):979-82.