Introduction: Laryngeal oedema caused by acquired angioedema due to C1-inhibitor deficiency (C1-INH-AAE) is a life-threatening condition. The swelling is bradykinin mediated and will not respond to the usual treatment with antihistamines, corticosteroids, or epinephrine. Instead, kallikrein-bradykinin-targeted therapies should be used promptly to prevent asphyxiation.
Case presentation: A 43 years old female presented at the Hereditary Angioedema Centre reporting a one-year history of peripheral, facial, and neck oedema. Treatment with antihistamines and corticosteroids had been ineffective. Laboratory results showed complement level deficiencies and monoclonal gammopathy characterised as immunoglobulin M. An abdominal ultrasound revealed splenomegaly. A bone marrow biopsy was normal. Based on these data, the diagnosis of C1-INH-AAE associated with monoclonal gammopathy of uncertain significance (MGUS) was made. As C1-INH-AAE can present with life-threatening, standard treatment-resistant laryngeal oedema, an emergency care treatment plan was proposed, and the patient was advised to present to the emergency department (ED) with this medical letter. Based on these recommendations, three laryngeal attacks were successfully treated in the ED with recombinant human C1-inhibitor (two attacks) and fresh frozen plasma (one attack). After these episodes, the patient was prescribed prophylactic treatment with antifibrinolytics. No further angioedema attacks were reported by the patient at the 18 months follow-up visit.
Conclusions: Because angioedema of the upper airways is a life-threatening condition, recognising the specific type of swelling by the emergency physician is critical in providing immediate and effective treatment to reduce the associated risk of asphyxiation. C1-INH-AAE being a rare disorder, patients should have available an emergency care treatment plan with recommendations of acute treatment possibilities.