Isolated Small Intestine Angioedema: An Under-Recognized Complication of Angiotensin-Converting Enzyme Inhibitor Therapy

Abstract

Case Presentation: 58-year-old woman with history of hypertension, and recurrent episodic abdominal pain with extensive workup only remarkable for small intestine wall thickening on CT scan; presented to the emergency room with severe abdominal pain associated with non-bloody non-bilious vomitus and watery non-bloody diarrhea. Included in her medications: Enalapril. Examination revealed mild generalized abdominal tenderness. Laboratory indicated an unrevealing infectious workup, and a normal C4 and C1 esterase inhibitor. In previous admissions, bidirectional endoscopy revealed unspecific small bowel mucosal edema and inflammation. Several biopsies of the small intestine exhibited vascular congestion and non-specific mucosal inflammation. During this last admission, esophagogastroduodenoscopy and deep enteroscopy were performed. Endoscopic findings were small bowel edema and inflammation. Angiotensin converting enzyme inhibitors (ACEI) induced visceral angioedema was suspected and enalapril was held. Within 24 hours the patient reported significant improvement in her symptoms, with a repeated CT scan showing resolution of previous bowel thickening. Discussion: ACEI induced visceral angioedema commonly presents with a triad of severe acute abdominal pain (100%), vomiting (87%) and diarrhea (50%). Laboratory tests are frequently unrevealing and CT scan of the abdomen demonstrate segmental thickening of the bowel wall, most commonly involving the jejunum, ileum, and duodenum. Symptoms typically resolve within 24 to 48 hours of stopping the medication. This condition may occur any time during the course of therapy. It is most frequent in women (85% of cases) with a mean age of 50 years. There is frequently a delay in diagnosis before the culprit medication is eventually stopped; and patients usually underwent invasive work up. It is important to rule out hereditary angioedema by testing for C1 esterase inhibitor and C4 level. Diagnosis is established by current use of an ACEI, abdominal pain, CT showing bowel-wall thickening, normal C1-esterase inhibitor level and resolution of symptoms and normal imaging after cessation of ACE inhibitor. Conclusion: Visceral angioedema should be considered in patients using ACE inhibitors with unexplained abdominal pain, early recognition and discontinuation of ACE inhibitors can avoid considerable morbidity, unnecessary medical and surgical interventions. Cessation of ACE inhibitors leads to symptom resolution.Figure: Severe Jejunum walls thickening on CT scan.Figure: Resolved jejunum wall thickening after discontinuing ACEI.Figure: Edematous Small intestine villi with inflammatory changes.