Case study links blood pressure drug to woman’s stomach pain

A case report attributed a woman’s repeated episodes of severe abdominal pain to angioedema occurring as a side effect of enalapril, a type of angiotensin-converting enzyme (ACE) inhibitor used to lower blood pressure. Discontinuing the drug after years of treatment led to complete and lasting recovery.

“Imaging provided the key diagnostic clue,” researchers in Spain wrote in the case report, “ACE Inhibitor-Induced Isolated Visceral Angioedema: A Diagnostic Pitfall Mimicking Inflammatory Bowel Disease,” published in the Journal of Investigational Allergology and Clinical Immunology.

ACE inhibitors are used to treat high blood pressure and protect the heart. However, these medications can increase bradykinin, a substance that causes blood vessels to widen and become more permeable. This can cause angioedema, swelling resulting from fluid leaking from blood vessels into surrounding tissue. Although rare, swelling can occur in the intestines.

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The 50-year-old woman had been taking enalapril (marketed as Vasotec and others) at a dose of 10 mg daily for five years. She experienced repeated episodes of severe abdominal pain, swelling, nausea, vomiting, and sudden, severe diarrhea. Each episode lasted up to 10 days and then resolved on its own. The episodes had become more frequent over time.

During one episode, a computed tomography (CT) scan of her abdomen showed swelling throughout the walls of the jejunum and ileum, parts of the small intestine. The scan also showed swelling in the inner layers of the intestinal wall and enlarged blood vessels in the tissue supporting the intestines. Some fluid had collected in her abdomen.

Four weeks after her angioedema symptoms resolved, magnetic resonance enterography, a type of MRI used to examine the small intestine, showed that the swelling and abdominal fluid had disappeared. The intestinal loops and walls had returned to normal, suggesting temporary swelling rather than a long-term inflammatory disease. The comparison between the CT scan and the later MRI was key to the angioedema diagnosis.

Doctors concluded that the woman had ACE inhibitor-induced abdominal angioedema. The diagnosis was based on her symptoms, the characteristic imaging findings, the complete disappearance of swelling between episodes, and the exclusion of other possible causes. Symptoms began five years after she started enalapril, which could have led the doctors to overlook the medication as a cause, the researchers noted.

Treatment with enalapril was discontinued. Within four weeks, the woman’s symptoms disappeared completely.

“This outcome is consistent with the latest international guidelines for nonhereditary bradykinin-mediated angioedema, in which permanent withdrawal of [ACE inhibitors] is the only definitive treatment,” the researchers wrote.

ACE inhibitor-induced abdominal angioedema should be considered in patients with repeated episodes of abdominal pain, vomiting, and diarrhea, especially when routine gastrointestinal tests do not explain the symptoms, the researchers said. Early recognition and discontinuation of the ACE inhibitor can lead to recovery while avoiding unnecessary treatments.