A 16-year-old girl develops generalized urticaria, angioedema of the lips, and audible wheezing minutes after ingesting peanuts at a school cafeteria. Vital signs show BP 88/54 mmHg, HR 118/min, RR 22/min, and SpO2 94% on room air. Auscultation reveals diffuse expiratory wheezes bilaterally. She denies prior anaphylaxis or known allergies. Epinephrine 0.3 mg intramuscular is administered immediately into the anterolateral thigh. Serum tryptase level is elevated at 24 ng/mL, confirming mast cell degranulation. Which of the following combinations of receptor effects best explains the life-saving benefits of this drug?
- A)Alpha 2 mediated decreased sympathetic outflow and beta 1 blockade
- B)Dopamine receptor activation in the renal vasculature only
- C)Beta 1 blockade and beta 2 blockade
- D)Muscarinic blockade and nicotinic stimulation
- E)Alpha 1 mediated vasoconstriction and beta 2 mediated bronchodilationGABARITO
Explicação
Epinephrine is first line therapy for anaphylaxis because alpha 1 stimulation raises blood pressure and reduces mucosal edema, while beta 2 stimulation causes bronchodilation and reduces mediator release from mast cells. Beta 1 stimulation also supports cardia... Ver explicação completa e trilha adaptativa →