A term neonate develops hydrops fetalis. The mother had a flu-like illness with arthralgia in the second trimester. Fetal middle cerebral artery Doppler showed peak systolic velocity >1.5 MoM. Cord blood shows severe anemia with a positive PCR for which organism?
- A Rubella virus
- B Toxoplasma gondii
- C Parvovirus B19 ✓
- D Cytomegalovirus
Correct answer: C. Parvovirus B19
Explanation
Parvovirus C19 infects erythroid progenitor cells via the P antigen, causing severe fetal anemia, high-output cardiac failure, and hydrops fetalis. MCA-PSV >1.5 MoM is the standard Doppler marker for fetal anemia. This is the classic presentation. Rubella causes cardiac and auditory defects but not hydrops from anemia.
Reference: Nelson Textbook of Pediatrics, 21st ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.