Respiratory Herpes simplex virus at the intensive care unit: a prospective study

Background

Herpes simplex virus (HSV) can cause a variety of diseases including respiratory infections. A retrospective study performed at our hospital did not clarify the clinical and prognostic significance of HSV in the respiratory tract of critical care patients.

Objectives

A prospective study was conducted between November 1999 and July 2001 in order to evaluate the incidence and significance of respiratory HSV in ICU patients, to identify risk factors for the development of lower respiratory tract (LRT) infections with HSV and to study the origin of the virus.

Methods

Seven hundred and sixty-four patients admitted to our 30 bed ICU in a tertiary care hospital were examined for the presence of HSV in the upper (URT) and lower respiratory tract (LRT).

Results

One hundred and sixty-nine patients (22%) had HSV in the URT. The reactivation of the virus occurred within 10 days for 89% of all positive patients and followed a period of more severe disease as was indicated by SOFA max. In 58 (16.2%) of the 361 patients who had their LRT sampled, the virus was isolated from bronchusaspirate (BA) of broncho-alveolar lavage fluid (BAL). HSV in the throat was a highly significant risk factor (RR 11.6; 95% CI 5.51–23.84) for the development of LRT infections with the virus. Patients with more debilitating disease on admission and during ICU stay were more susceptible for HSV reactivation as was shown by APACHE II and SOFA scores. There was a significant association between HSV reactivation and ARDS (RR 2.94; 95% CI 1.6–5.41). The association between intubation and HSV reactivation was probably due to disease severity although patients with a long intubation (> 7 days) had a RR of 2.77 (95% CI 1.79–4.30) for reactivation of HSV, even when controlled for SOFA max. Patients with HSV reactivation had a longer ICU as compared to those without the virus.

Conclusion

HSV reactivation in ICU patients is more frequent than previously assumed. Reactivation of the virus in the throat is a major risk factor for the development of LRTI with the virus. Patients with HSV reactivation have a longer ICU stay as compared to controls. Further study on the effect of pre-emptive aciclovir therapy in these patients needs to be performed.