Cytomegalovirus. An unexpected cause of ventilator-associated pneumonia.
Cytomegalovirus (CMV) frequently is observed in immunocompromised hosts. The aim of this study was to report cases of ventilator-associated CMV pneumonia diagnosed by pathologic examination in intensive care patients without acquired immunodeficiency syndrome or hematologic malignancy or who were not receiving immunosuppressive agents. From June 1, 1989, to May 31, 1994, 2,785 patients were hospitalized. During the study period, 60 autopsies and 26 open-lung biopsies were performed in nonimmunocompromised patients who were seen with acute respiratory failure and/or symptoms suggestive of ventilator-associated pneumonia. Cytomegalovirus pneumonia was diagnosed using pulmonary samples by the identification of large cells with large nuclei containing a basophilic or eosinophilic inclusion surrounded by a light halo. These typical findings always were associated with a diffuse interstitial pneumonitis. Cytomegalovirus pneumonia was diagnosed after histologic examination in 25 patients. The reason for admission to the intensive care unit was major surgery in 13 patients and medical problems in 12 patients. Ventilator-associated CMV pneumonia was diagnosed by histologic examination 22.4 +/- 8.8 days after admission to the intensive care unit (median 18 days; range 10-40 days). The clinical description was similar with the 25 patients who were seen with ventilator associated CMV pneumonia and the 61 patients without ventilator-associated CMV pneumonia. However, there was a more severe hypoxemia 72 +/- 16 vs. 95 +/- 41 mmHg, P < 0.05) and a higher Weinberg's radiologic score (9.2 +/- 1.9 vs. 7.4. +/- 2.7, P < 0.05) in the ventilator-associated CMV pneumonia group. Diagnosis of ventilator-associated CMV pneumonia was made for 9 of 17 patients when shell-vial culture technique using fluorescein-labelled antibody E 13 was performed on bronchoalveolar lavage products. Four of the eight patients treated by ganciclovir therapy died of multiple organ dysfunction syndrome. The diagnosis of ventilator-associated CMV pneumonia should not be excluded in intensive care patients, even those without acquired immunodeficiency syndrome, hematologic malignancy, or immunosuppressive agents on admission.