Core EM - Emergency Medicine Podcast

Core EM - Emergency Medicine Podcast


Episode 212: Angioedema

August 01, 2025

Angioedema – Recognition and Management in the ED

Hosts:
Maria Mulligan-Buckmiller, MD
Brian Gilberti, MD

https://media.blubrry.com/coreem/content.blubrry.com/coreem/Angioedema.mp3 Download Leave a Comment Tags: Airway Show Notes Definition & Pathophysiology

Angioedema = localized swelling of mucous membranes and subcutaneous tissues due to increased vascular permeability.

Triggers increased vascular permeability → fluid shifts into tissues.

Etiologies
  • Histamine-mediated (anaphylaxis)
    • Associated with urticaria/hives, pruritus, and redness.
    • Triggered by allergens (foods, insect stings, medications).
    • Rapid onset (minutes to hours).
  • Bradykinin-mediated
    • Hereditary angioedema (HAE): C1 esterase inhibitor deficiency (autosomal dominant).
    • Acquired angioedema: Associated with B-cell lymphoma, autoimmune disease, MGUS.
    • Medication-induced: Most commonly ACE inhibitors; rarely ARBs.
    • Typically lacks urticaria and itching.
    • Gradual onset, can last days if untreated.
  • Idiopathic angioedema
    • Unknown cause; diagnosis of exclusion.
Clinical Presentations
  • Swelling
    • Asymmetric, non-pitting, usually non-painful.
    • May involve lips, tongue, face, extremities, GI tract.
  • Respiratory compromise
    • Upper airway swelling → stridor, dyspnea, sensation of throat closure.
    • Airway obstruction is the most feared complication.
  • Abdominal manifestations
    • Bowel wall angioedema can mimic acute abdomen:
      • Nausea, vomiting, diarrhea, severe pain, increased intra-abdominal pressure, possible ischemia.
Key Differentiating Features
  • Histamine-mediated: rapid onset, hives/itching, resolves quickly with epinephrine, antihistamines, and steroids.
  • Bradykinin-mediated: slower onset, lacks urticaria, prolonged duration, less responsive to standard anaphylaxis medications.
Diagnostic Approach in the ED
  • Focus on airway (ABCs) and clinical assessment.
  • Labs (e.g., C4 level) useful for downstream diagnosis (esp. HAE) but not for acute management.
  • Imaging: only if symptoms suggest abdominal involvement or to rule out other causes.
Treatment Strategies
  • Airway protection is always priority:
    • Early consideration of intubation if worsening obstruction or inability to manage secretions.
  • Histamine-mediated (anaphylaxis):
    • Epinephrine (IM), antihistamines, corticosteroids.
  • Bradykinin-mediated:
    • Epinephrine may be tried if unclear etiology (no significant harm, lifesaving if histamine-mediated).
    • Targeted therapies:
      • Icatibant: bradykinin receptor antagonist.
      • Ecallantide: kallikrein inhibitor (less available).
      • C1 esterase inhibitor concentrate: replenishes deficient protein.
      • Fresh frozen plasma (FFP): contains C1 esterase inhibitor.
      • Tranexamic acid (TXA): off-label, less evidence, considered if no other options.
Complications to Watch For
  • Airway compromise: rapid deterioration possible.
  • Abdominal compartment syndrome from bowel edema (rare, surgical emergency).
Take-Home Points
  • Secure the airway if in doubt.
  • Differentiate histamine-mediated vs bradykinin-mediated by presence/absence of hives/itching and speed of onset.
  • Use epinephrine promptly if suspecting histamine-mediated angioedema or if uncertain.
  • Consider bradykinin-targeted therapies for confirmed hereditary, acquired, or ACE-inhibitor–related angioedema.
  • Recognize ACE inhibitors as the most frequent medication trigger; ARBs rarely cause it.
  • Labs and imaging generally don’t change initial ED management but aid diagnosis for follow-up care.

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