Life-Threatening Laryngeal Angioedema in C1-Esterase Inhibitor Deficiency: A Possible Propofol-Associated Exacerbation

Background

Hereditary angioedema (HAE) secondary to C1-esterase inhibitor (C1-INH) deficiency is a rare bradykinin-mediated disorder that can cause severe, potentially fatal airway edema. Identification of precipitating or exacerbating factors is critical when angioedema persists despite treatment. Propofol is commonly used for induction and sedation during mechanical ventilation and contains soybean oil. Although propofol-associated hypersensitivity and angioedema are rare, its potential role in patients with underlying angioedema warrants consideration.

Case Presentation

An 83-year-old woman with hypertension and a lifelong history of recurrent angioedema presented with acute, progressively worsening dyspnea, stridor, and upper-airway edema requiring emergent endotracheal intubation. Propofol was administered for induction and continued for sedation. Laboratory evaluation demonstrated a decreased C4 level, supporting an underlying C1-INH deficiency-associated angioedema. Despite treatment with corticosteroids, antihistamines, racemic epinephrine, bronchodilators, and antibiotics, significant airway edema persisted, resulting in prolonged mechanical ventilation. Review of her medical history identified a documented soybean allergy. Because propofol contains soybean oil, propofol was considered a potential contributor to the persistent angioedema and was discontinued. Following discontinuation, the patient's airway edema progressively improved and C4 levels stabilized. On ICU day 6, she demonstrated a positive cuff-leak test, successfully completed a spontaneous breathing trial, and was extubated.

Results / Findings

The patient's angioedema failed to improve despite conventional therapy while receiving propofol and subsequently improved after propofol discontinuation. Stabilization of C4 levels occurred concurrently with clinical improvement, and the patient was successfully liberated from mechanical ventilation. The combination of lifelong recurrent angioedema, low C4, documented soybean allergy, propofol exposure, persistent airway edema, and improvement following propofol discontinuation raised concern for a propofol-associated exacerbation of underlying C1-INH deficiency-mediated angioedema.

Discussion & Conclusion

This case highlights a potentially important interaction between an underlying bradykinin-mediated angioedema disorder and exposure to a medication capable of provoking hypersensitivity reactions. In patients with suspected or known HAE who develop persistent airway edema after intubation, clinicians should reassess medications and potential allergens rather than assuming that ongoing edema represents the natural course of HAE alone. The temporal improvement following propofol discontinuation and subsequent identification of soybean allergy suggest a possible association between propofol exposure and exacerbation of this patient's angioedema. Although causality cannot be established from a single case, this case emphasizes the importance of reviewing allergy histories and medication ingredients when managing life-threatening angioedema.