Intestinal Hereditary Angioedema was Mistaken for Infectious Colitis in Case Report

Intestinal hereditary angioedema (HAE) should be considered as a possible cause of abdominal pain, even in patients with normal C1 inhibitor protein levels, suggests a case report study that described a woman with HAE being misdiagnosed with infectious colitis.

The case study, “Wolf in the sheep’s clothing: intestinal angioedema mimicking infectious colitis,” was published in BMJ Case Reports.

Hereditary angioedema is a rare, potentially life-threatening, genetic disorder characterized by sudden and recurrent episodes of swelling in the face, tongue, hands, feet, gastrointestinal (GI) tract, genitalia, and upper airways.

The disease is caused by genetic mutations in the SERPING1 gene, leading to lower levels of C1 inhibitor (C1-INH) protein — in the case of HAE type 1 — or to a dysfunctional C1-INH protein, which is the case in HAE type 2.

However, in HAE type 3, which is normally associated with mutations in the coagulation factor XII (F12) gene, the levels of C1-IHN protein remain normal.

The case report study described a 48-year-old woman with HAE type 3 who was believed to have infectious colitis, an inflammation of the bowel normally triggered by harmful bacteria or parasites.

The woman was admitted to hospital after complaining about nausea, vomiting, diarrhea, and severe abdominal pain the previous day. Over the course of one year, she had been hospitalized six times for suspected infectious colitis, but all tests for it came back negative. During these episodes, she was prescribed  antibiotics, which did little to relieve her symptoms. Besides multiple hospital admissions for infectious colitis, she also had an extensive medical history of irritable bowel syndrome.

Examinations found no signs of bowel infection, liver or kidney problems, abnormal blood cell count, or low levels of C1-INH. However, they did reveal signs of excessive bowel thickening. Medical history re-analysis showed the patient had two relatives diagnosed with angioedema.

Based on these observations, doctors diagnosed the patient with HAE manifesting itself through GI symptoms, and did not prescribe antibiotics. She kept having multiple daily pain episodes in the hospital, which failed to be kept under control with steroids and anti-histamine medications. However, after five days, her recurrent abdominal pain subsided, and she was kept on intravenous normal saline fluid and pain killers.

Eventually she was discharged and recovered well with conservative treatment. Six months after her last hospital admission, the patient showed no signs of severe abdominal pain and continued to do well.

“Intestinal angioedema should be considered as a possible cause of abdominal pain especially in cases of recurrent intractable symptoms and in patients with positive history of HAE,” the researchers wrote.

Investigators also emphasized that unlike other types, “HAE type 3 does not require glucocorticoids and anti-histamine (medications) as compared with acquired HAE. It (has been) successfully managed with icatibant (Firazyr) in previous cases but can also be managed supportively with analgesics and intravenous fluids as in our case.”

In addition, long-term preventive treatment with Danocrine (danazol) or Cyklokapron (tranexamic acid) “should be considered in patients who have at least one or more severe episodes a month, who are unable to perform their usual activities more than 5 days a month, and those with a history of a laryngeal attack,” the researchers stated.