PIV type 3 induced necrotizing pneumonia

Necrotizing pneumonia (NP) in children is typically associated with severe bacterial infection, whereas virus-associated NP remains uncommon and poorly characterized. We report a 16-month-old previously healthy boy with severe community-acquired pneumonia that evolved into bilateral necrotizing lesions, confirmed by contrast-enhanced computed tomography despite gradual clinical improvement. Parainfluenza virus type 3 was detected at high load by real-time polymerase chain reaction of bronchoalveolar lavage, whereas microbiological investigations for bacteria and mycobacteria were negative. As a result, parainfluenza virus type 3 was considered the pathogen most strongly associated with disease progression, although an early bacterial process cannot be completely excluded given prior antibiotic exposure. The child recovered without respiratory failure or hemodynamic compromise, and follow-up imaging showed near-complete resolution. This case highlights that radiographic progression to NP does not automatically mandate an escalation of broad-spectrum antibiotics when a viral etiology is supported and the patient is clinically improving.