Viral ventilator-associated pneumonia: uncovering tip of the iceberg

Hospital-acquired infections are frequently encountered by the physicians for ailments demanding prolonged hospitalization, especially in intensive care units, where patients are often mechanically ventilated. The organisms most often implicated are bacteria; viral etiology is infrequent.

The study aims at reviewing lung pathology at autopsy in mechanically ventilated children admitted in pediatric intensive care unit (PICU) to assess the incidence of viral ventilator-associated pneumonias (VAP).

Retrospective analysis.

Among the 275 children who had been autopsied, 13 who had been admitted in the PICU satisfied the criteria for VAP. These cases were analyzed on the basis of clinical data and pulmonary pathology. Depending on the overall histology, the cases were classified as being viral or bacterial in etiology. Immunohistochemistry (IHC) for detection of viral antigens was also performed.

Of the 13 children, nine (five males and four females) had shown the histomorphologic features, suggesting viral inflammation. The mean age was 33 months. Falling oxygen saturation and increasing respiratory distress had necessitated ventilator support. Acute lymphocytic bronchiolitis, interstitial pneumonitis, diffuse alveolar damage, and necrotizing pneumonia were the histological features. The viruses identified in five patients were adenovirus, respiratory syncytial virus and cytomegalovirus.

This communication, though not representing the true incidence, emphasizes that a proportion of nosocomial infections is due to viral infections. This should alert the treating intensivists to actively pursue investigations to confirm viral etiology.