2635 Gastrointestinal Hereditary Angioedema Causing Recurrent, Self-Resolving Abdominal Pain

Abstract

INTRODUCTION: Hereditary angioedema (HAE) is a type of bradykinin-mediated isolated angioedema, characterized by temporary swelling that can affect skin or walls of hollow viscera such as the oropharynx, or gastrointestinal tract (in 43 to 93% of HAE cases respectively) and occurs without pruritus. This case is reported due to its rare presentation that often results in unnecessary invasive procedures. CASE DESCRIPTION/METHODS: A 25-year-old female with a past medical history of hypothyroidism and asthma presented with acute on chronic intermittent abdominal pain and vomiting for a day bearing no relation with meals or defecation. She had recurrent hospitalizations for similar complaints but workup till date showed enteritis on imaging and exploratory laparoscopy showed adhesions with colonic biopsy negative. Extensive history taking revealed prodromal symptom of anxiety and a previous episode of self-resolving finger swelling, retrospectively suspected to be due to angioedema. Labs showed leukocytosis and elevated CRP. Repeat CECT abdomen displayed thickening of jejunal wall. Given her history of prodromal symptoms, finger swelling and a family history of similar self-resolving abdominal pain of unclear etiology in her mother prompted further testing for complements due to concern for hereditary angioedema, which was positive with low C4 and C1 inhibitor. She was referred to an allergy specialist for further management. DISCUSSION: HAE is an autosomal dominant disease that is due to decreased or impaired C1 Inhibitor. Typical GI symptoms are recurrent abdominal pain, vomiting and diarrhea caused by transient small bowel edema. Inciting events include stressful situations like fasting and infections and medicines like ACE-inhibitors. Diagnosis is clinical from history of skin swelling or respiratory distress during attacks, documenting possible triggers and family history of HAE. Physical exam and imaging is useful only during acute attacks. Recommended lab tests include C4 levels, C1 inhibitor antigenic levels, and C1INH functional levels. Endoscopy is not recommended as it may precipitate laryngoedema. Treatment includes C1 INH replacement or icatibant (bradykinin receptor antagonist) for acute attacks and attenuated androgen or lanadelumab for prophylaxis. HAE should be considered when tackling cases of undiagnosed abdominal pain in the right clinical context to prevent years of suffering, unnecessary invasive procedures and life-threatening complications from laryngeal edema or hypovolemic shock.