Episode 212: Angioedema

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. Read More

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