• Clinical science

Angioedema

Abstract

Angioedema is a self-limited, localized swelling of the dermis, subcutaneous tissues, and/or submucosal tissues caused by fluid leakage into the interstitial tissue. It is mediated by vasoactive substances and can be classified as either mast cell-mediated (often secondary to allergic reactions and NSAIDs), bradykinin-mediated (due to ACE inhibitor use or enzyme deficiencies), and unknown (idiopathic). Patients usually present with swelling of the eyelids, lips, and tongue. However, life-threatening laryngeal edema may occur, which requires immediate airway protection. Treatment generally consists of supportive care and avoidance of triggers, if applicable. In acute cases, mast cell-mediated angioedema is treated with systemic glucocorticoids, antihistamines and if necessary, epinephrine for anaphylaxis. Bradykinin-mediated angioedema is treated with C1 inhibitor (C1-INH) concentrate, bradykinin-B2-receptor antagonists and kallikrein inhibitors.

Classification

Mast cell-mediated angioedema (histamine-mediated angioedema)

Bradykinin-mediated angioedema

Angioedema of unknown cause

References:[1][2][3][4][5]

Clinical features

Common symptoms

  • Facial edema (mouth, eyelids, tongue)
  • Laryngeal involvement: dyspnea and inspiratory stridor, potentially life-threatening
  • Possibly swelling of extremities and urogenital area (e.g., hands, feet, scrotum)

Mast cell-mediated angioedema

Bradykinin-mediated angioedema

  • Hereditary angioedema
    • Family history often present
    • Clinical manifestations in childhood or adolescence
    • Abdominal symptoms : colicky abdominal pain, nausea/vomiting, diarrhea
    • Angioedema of the extremities or trunk
    • Not associated with urticaria or pruritus

References:[5]

Diagnostics

  • The diagnosis of angioedema is mainly based on history and clinical findings.
  • In some cases:
    • Allergy screening
    • Evaluation of C1-INH deficiency: C1-INH, ↓ C4

Treatment

Epinephrine, glucocorticoids and antihistamines are ineffective in acute hereditary angioedema attacks!

If airway compromise is suspected (stridor, wheezing, diminished air movement) or the patient is in shock, treat immediately with IM epinephrine, start oxygen and IV fluids, and consider intubation to protect the airway. Once acute therapy has been initiated, the type and cause of angioedema should be determined.
References:[6][7][8]