The case of a patient with acquired angioedema who presented with abdominal pain as the first and only major symptom of the disease has been published in BMJ Case Reports

Acquired angioedema differs from hereditary angioedema (HAE) in that the C1-inhibitor deficiency is acquired whereas in HAE, the deficiency is due to mutations affecting the SERPING1 gene. 

The case study as presented details a female in her 50s with acute abdominal pain. The pain was described as colicky and was accompanied by nausea and vomiting. She did not have a family history of gastrointestinal disease. 

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Upon physical examination, the patient was pale and clammy. An abdominal examination revealed a diffusely tender upper abdomen with no voluntary guarding. Bowel sounds were present and normal. 

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Laboratory investigations revealed slightly elevated C-reactive proteins and leukocyte count; other parameters were normal. An abdominal computed tomography (CT) scan revealed a thickened ileum wall with surrounding ascites. 

The patient was admitted and her abdominal pain resolved spontaneously within 2 days, with an evident decline in free peritoneal fluid. 

Six and 8 weeks after this admission, the patient presented again with comparable episodes of acute abdominal pain with transient ascites that spontaneously resolved within a few days. Upon her third admission, additional laboratory tests revealed a marked decrease in C1-inhibitor activity level (0.35 E/mL), with undetectable low C1q and C4 levels. This was consistent with a diagnosis of acquired C1 inhibitor deficiency. 

A repeat abdominal CT scan revealed that the spleen had increased in size from 140 to 147 mm. Additional positron emission tomography scan and bone marrow biopsy suggested that this was due to splenic marginal zone lymphoma. 

“Since our patient experienced disabling symptoms mostly due to the acquired C1-INH deficiency, she was treated with a total of 4 weekly doses of rituximab monotherapy, which is currently identified as the most effective therapy for [splenic marginal zone lymphoma],” the authors wrote. 

This patient remained symptom free for 9 months after treatment and was able to resume her daily activities. 


Hanevelt J, de Vos Tot Nederveen Cappel WH. Presentation of an extraordinary colic: abdominal pain as the first and only utterance of an acquired C1-inhibitor deficiencyBMJ Case Rep. 2022;15(10):e250710. doi:10.1136/bcr-2022-250710