Hypersensitivity Reactions

A 28-year-old woman presents to the emergency department with acute onset of facial angioedema, urticaria, and dyspnea 15 minutes after receiving intravenous penicillin for a urinary tract infection. She reports a history of similar reactions to cephalosporins. On examination, she is anxious, with wheezing audible on auscultation, blood pressure 88/54 mmHg, and heart rate 118/min. Serum tryptase level is markedly elevated. Which of the following best describes the pathophysiologic mechanism underlying this reaction?

A 28-year-old woman presents with acute anaphylaxis following a penicillin injection for pneumonia. She develops severe bronchospasm, hypotension, and angioedema within 5 minutes of drug administration. What is the drug of choice for immediate management of this Type I hypersensitivity reaction?

Which of the following cytokines is primarily responsible for the delayed-type hypersensitivity (Type IV) reaction mediated by T cells?

A 35-year-old man with a history of rheumatoid arthritis develops a maculopapular rash, fever, and joint pain 7 days after starting a new antibiotic. Laboratory studies show elevated ESR, circulating immune complexes, and low serum complement levels. Which of the following is the most common organ system affected by Type III hypersensitivity (immune complex-mediated) disease in clinical practice?

A 35-year-old man develops severe serum sickness-like reaction 10 days after receiving intravenous cephalosporin for meningitis. He presents with fever, arthralgia, lymphadenopathy, and urticarial rash. What is the drug of choice for managing this Type III hypersensitivity reaction?