A 3-year-old child presents with fever for 10 days, bilateral cervical lymphadenopathy, pharyngeal exudate, and hepatosplenomegaly. Peripheral blood smear shows >10% atypical lymphocytes. Heterophile antibody test (Monospot) is positive. Which is the most common causative agent?
- A Epstein-Barr virus ✓
- B Cytomegalovirus
- C Human herpesvirus 6
- D Toxoplasma gondii
Correct answer: A. Epstein-Barr virus
Explanation
Infectious mononucleosis classically presents with fever, lymphadenopathy, pharyngitis, hepatosplenomegaly, and atypical lymphocytes. B positive heterophile antibody (Monospot) test is specific for Epstein-Barr virus (EBV) infection. CMV can cause a mononucleosis-like syndrome but is heterophile antibody negative. HHV-6 causes roseola; Toxoplasma causes lymphadenopathy without pharyngitis.
Reference: Nelson Textbook of Pediatrics, 21st ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.