Gastrointestinal: Small intestinal angioedema induced by angiotensin‐converting enzyme inhibitors

A 23-year-old woman with no specific allergies or family history of disease presented with acute abdominal pain 2 months after the administration of the angiotensin-converting enzyme inhibitor (ACEI) enalapril. Laboratory tests revealed significantly increased D-dimer levels (> 20.00 μg/mL). Abdominal computed tomography (CT) (Fig. 1) indicated diffuse swelling and thickening (approximately 5.5 mm) of the small intestine, primarily in groups 3–4, with evident enhancement showing the target sign. Mesenteric edema, perihepatic and perisplenic effusions, and massive pelvic effusions were also noted. A multipoint biopsy of the gastrointestinal mucosa revealed no significant eosinophilic infiltration. The patient's condition rapidly improved, and the D-dimer level rapidly decreased following enalapril discontinuation and supportive care, without the use of antibiotics. Additionally, follow-up abdominal CT (Fig. 2) indicated that the diffuse thickening of the small intestine in the original left middle and lower abdomen had improved. Furthermore, the pelvic and abdominal effusions were absorbed. The patient experienced similar symptoms after 2 months of perindopril use, and severe swelling and thickening of the small intestine (similar position) were observed, with the D-dimer levels significantly increasing again. Following the discontinuation of perindopril, the patient's abdominal pain was relieved. Angioedema is an adverse reaction that can occur days to months after ACEI administration, with an incidence of approximately 0.1–0.7%.1, 2 It can involve the face, upper airway, and gastrointestinal mucosa, presenting a potentially life-threatening risk.3 However, it can be easily misdiagnosed in patients with acute gastrointestinal symptoms. This case provides valuable insights into understanding ACEI-induced small intestinal angioedema by describing similar clinical manifestations and CT changes following two different ACEIs administered to a single patient. During both episodes, we observed a significant increase in D-dimer levels at disease onset and a rapid decrease to normal levels as the condition improved, suggesting that elevated D-dimer levels may serve as a diagnostic marker for ACEI-induced angioedema, which has not been mentioned in previous literature.