Herpes Lung Infection Common in Ventilated Patients

Herpes simplex virus (HSV) lung infection occurs fairly often in immunocompetent patients undergoing lengthy periods of mechanical ventilation, claims a new study.

Researchers at the Groupe Hospitalier Pitie-Salpetriere (Paris, France) conducted a prospective observational study of all immunocompetent patients admitted to the hospital undergoing mechanical ventilation for at least five days. Biopsies were obtained for all who deteriorated clinically with suspected lung infection. HSV bronchopneumonitis was defined as this deterioration when associated with HSV in oropharyngeal swabs, or bronchial and HSV-specific nuclear inclusions in cells recovered during bronchoalveolar lavage or bronchial biopsies.

HSV was detected in the respiratory track of more than half of these patients, and HSV bronchopneumonitis was diagnosed in 42 (21%) of the 201 who deteriorated clinically during the study period. The mean duration of mechanical ventilation before diagnosis was 14 days. Risk factors associated with HSV bronchopneumonitis were oral-labial lesions, HSV in the throat, and macroscopic bronchial lesions seen during bronchoscopy. At admission, patients who subsequently developed HSV bronchopneumonitis were comparable to those without the disease. However, their courses were more complicated and they had a longer duration of mechanical ventilation and spent more time in intensive care. The study was reported in the May 1, 2007, issue of the American Journal of Respiratory and Critical Care Medicine.

"In non-immunocompromised patients requiring prolonged mechanical ventilation, some episodes of clinical deterioration--leading to the suspicion of bacterial ventilator-associated pneumonia--are in fact due to an infection of the lower respiratory tract by HSV,” said lead author Dr. Charles-Edouard Luyt.

It is not yet known whether the isolation of HSV from lower respiratory tract samples of non-immunocompromised ventilated patients corresponds to bronchial contamination from the mouth and/or throat, local tracheobronchial excretion of HSV, or true HSV lung involvement (bronchopneumonitis) with its own morbidity/mortality.


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