A 34-year-old man is admitted to the hospital for treatment of severe community-acquired pneumonia. Ten minutes after the initiation of his first dose of intravenous ceftriaxone, he reports sudden-onset throat tightness, severe chest pain, and a feeling of impending doom. Physical examination reveals diffuse urticaria, marked angioedema of the lips and tongue, and audible expiratory wheezing. Vital signs show a temperature of 37.2°C (99.0°F), a heart rate of 138/min, and a blood pressure of 72/40 mm Hg. The physician immediately recognizes a severe, IgE-mediated immunologic emergency.
Arrange the following acute management steps in the most appropriate chronological order for this type I hypersensitivity reaction.
- 1Immediately discontinue the intravenous ceftriaxone infusion to halt further allergen exposure.
- 2Administer intramuscular epinephrine into the anterolateral thigh.
- 3Initiate rapid intravenous crystalloid resuscitation to support intravascular volume.
- 4Administer intravenous methylprednisolone to mitigate late-phase inflammation.
Answer
The correct sequence is: (1) Discontinue the ceftriaxone infusion, (2) Administer intramuscular epinephrine, (3) Initiate rapid intravenous fluid resuscitation, and (4) Administer intravenous methylprednisolone.
The management of acute anaphylaxis (Type I hypersensitivity) follows a strict hierarchy of clinical stabilization and targeted immunologic rescue. First, the inciting antigen must be removed to prevent ongoing IgE cross-linking. Second, intramuscular epinephrine must be administered immediately as the primary life-saving intervention. Epinephrine reverses peripheral vasodilation (alpha-1), causes bronchodilation (beta-2), and decreases further mediator release from mast cells. Third, because anaphylaxis involves massive capillary leak and distributive shock, rapid intravenous fluid resuscitation is required to restore preload. Finally, adjunctive medications such as glucocorticoids are given to downregulate the delayed inflammatory response and prevent a biphasic reaction, but they have no immediate effect and must be given last in this sequence.
Step-by-Step Solution
Key Concept
Acute management sequencing in Type I Hypersensitivity (Anaphylaxis)
Estimated Time:1m 0s