Case Studies in Toxicology: Angioedema Post-tPA: Hemorrhage Is Not the Only Risk Factor
Endotracheal Intubation. Providers should have a low threshold for endotracheal intubation, which should ideally be performed in any patient at risk for airway compromise.4 Due to the extensive airway swelling that can occur in the setting of angioedema, airway intervention should optimally be performed by an available clinician with the most skill and experience in this area. It is wise to be prepared to utilize advanced airway techniques, if available, including fiberoptic laryngoscopy or potentially cricothyrotomy.
Histamine Agonists. Standard therapy for patients who develop angioedema should include histamine antagonists, such as diphenhydramine (H1 antagonist) and famotidine (H2 antagonist) along with corticosteroids. Although these therapies are unlikely to be helpful in the treatment of tPA-induced angioedema, the difficulty in excluding allergic angioedema and the low risk of adverse effects associated with these medications support their use.
Fresh Frozen Plasma. Fresh frozen plasma (FFP) should be considered for patients who have a history of hereditary angioedema. Fresh frozen plasma contains enzymes that degrade bradykinin. Although FFP has been used successfully in the treatment of ACEI-induced angioedema, its use (or benefit) in tPA-related cases is not clear.
Icatibant. A selective bradykinin B2-receptor antagonist, icatibant has been used to treat patients with ACEI-induced angioedema because of its effects on bradykinin receptors. Comparison of the efficacy of icatibant to the prevailing treatment strategy of diphenhydramine, famotidine, and methylprednisolone found a shorter time to symptom relief with icatibant.7 However, icatibant is extremely expensive ($23,000/30 mg). As previously mentioned, based on its similar mechanism of action, lower cost, and safety profile, FFP can be given (off label) in this situation.
Case Conclusion
The patient was given diphenhydramine, famotidine, and methylprednisolone, but did not show any improvement. His upper/lower lip swelling continued to worsen, and 30 minutes after the onset of angioedema, he was unable to open his mouth more than 1 cm.
Multiple attempts to perform awake fiberoptic intubation failed due to inadequate sedation; however, intubation was successfully performed following light sedation. The patient self-extubated in the ICU on hospital day 3, and the angioedema had progressively decreased. Angioedema and weakness completely resolved by hospital day 4, and he was discharged home on hospital day 7.
