An 11-year-old girl is brought to the office for a health maintenance visit. She feels well and has no chronic medical conditions. As part of routine care, the patient receives a first dose of the quadrivalent meningococcal conjugate vaccine and the 9-valent human papillomavirus vaccine. Five minutes later, while being escorted to the waiting area, the patient appears pale and reports feeling dizzy. She immediately loses consciousness, but a fall is prevented by the health care provider. Blood pressure is 70/40 mm Hg and pulse is 46/min. On physical examination, the patient has normal lung and heart sounds. There is no rash. Which of the following is the most likely cause of this patient's syncope?

Question

An 11-year-old girl is brought to the office for a health maintenance visit.  She feels well and has no chronic medical conditions.  As part of routine care, the patient receives a first dose of the quadrivalent meningococcal conjugate vaccine and the 9-valent human papillomavirus vaccine.  Five minutes later, while being escorted to the waiting area, the patient appears pale and reports feeling dizzy.  She immediately loses consciousness, but a fall is prevented by the health care provider.  Blood pressure is 70/40 mm Hg and pulse is 46/min.  On physical examination, the patient has normal lung and heart sounds.  There is no rash.  Which of the following is the most likely cause of this patient's syncope?

Quizplus · Accepted Answer

Eductional Objective: Vasovagal syncope is a known complication of vaccine administration, particularly in adolescents.  It typically involves a prodrome and can be differentiated from anaphylaxis based on skin findings (pallor vs urticaria), absence of respiratory symptoms (eg, upper airway edema, bronchospasm), and presence of bradycardia (vs tachycardia).

An 11-Year-Old Girl Is Brought to the Office for a Health