SHM Converge Scientific Abstract ePoster Gallery-The Kitchen Sink Approach: A Case of Idiopathic Non-Histaminergic Angioedema

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This case describes a 68-year-old man with recurrent angioedema who presented with progressive tongue swelling and shortness of breath. In the emergency department, he received epinephrine, methylprednisolone, diphenhydramine, and famotidine, but his symptoms worsened and he required emergency intubation for airway protection. On exam, he had significant tongue and lip swelling without urticaria, abdominal swelling, or extremity swelling. His home medications included aspirin and cilostazol.<br /><br />Despite standard therapy with steroids, antihistamines, and IV fluids, he showed little improvement until he was given two doses of human C1 esterase inhibitor, after which his swelling improved and he was successfully extubated. A detailed history after extubation did not identify a clear trigger. He was discharged on loratadine, famotidine, and a prednisone taper, and was advised to stop aspirin and cilostazol and follow up with an allergist.<br /><br />Laboratory evaluation showed elevated creatinine, normal C1 inhibitor antigen and C4 levels, normal C1q, normal tryptase, and plasma histamine at the upper limit of normal, supporting a non-histaminergic process rather than classic allergic angioedema. Because his episode did not respond to typical anaphylaxis treatment, he was diagnosed with idiopathic angioedema, likely idiopathic non-histaminergic angioedema.<br /><br />The report emphasizes that angioedema can be histamine-mediated or bradykinin-mediated, with the latter often involving tongue and mucosal swelling and responding poorly to antihistamines and steroids. It also highlights the challenge of acute management, as treatments such as C1-INH, tranexamic acid, and fresh frozen plasma may be helpful, while standard allergy medications are often ineffective.

Asset Subtitle

Vickie Xin

Meta Tag

Author List Bhavin Patel, Vickie Xin

Category Clinical Vignettes

Concept Angioedema

Concept Idiopathic non-histaminergic angioedema

Concept Tongue Swelling

Concept Airway Protection

Concept Histamine

Distinguished Non-Finalist

Presenter Organization Corewell Health William Beaumont University Hospital

Presenting Author Vickie Xin

Track Adult

Keywords

angioedema

tongue swelling

airway obstruction

C1 esterase inhibitor

non-histaminergic angioedema

bradykinin-mediated

intubation

aspirin

cilostazol

idiopathic angioedema

Angioedema

Idiopathic non-histaminergic angioedema

Tongue Swelling

Airway Protection

Histamine