Refractory Anaphylaxis and Near-Fatal Anaphylaxis: Two Overlapping Clinical Observations of Severe Anaphylaxis

The terms refractory anaphylaxis and near-fatal anaphylaxis have gained prominence in the last 5-10 years. Refractory anaphylaxis has a clinical justification in that patients often do not respond to successive doses of adrenaline. Near-fatal anaphylaxis facilitates the study of fatal anaphylaxis, which is 10 times less frequent. In terms of epidemiology, refractory anaphylaxis and near-fatal anaphylaxis overlap, since refractory anaphylaxis can prove fatal, and the more severe the anaphylaxis (including cardiorespiratory arrest), the greater the need for adrenaline and fluid infusion. However, no specific pathogenesis or treatment has been described for either condition. Consequently, these are not distinct clinical entities, but different manifestations of severity. The risk factors for both types of anaphylaxis are the same as those described for severe anaphylaxis, namely, patient age, cardiac and respiratory comorbidities, and the (controversial) role of ß-blockers and angiotensin-converting enzyme inhibitors. If volume expansion and adrenaline infusion prove ineffective, treatment is based on intubation, ventilation, intravenous vasopressors, and glucagon. Patients should be transferred to the intensive care unit. This review provides a panoramic epidemiologic vision of both manifestations of severe anaphylaxis. We conclude that they share many risk factors and often occur together in severe anaphylaxis. Therefore, each should be considered a manifestation of severe anaphylaxis.