Neurologic outcome of VZV encephalitis one year after ICU admission: a multicenter cohort study

Varicella-zoster virus (VZV) is one of the main viruses responsible of acute encephalitis. However, data on the prognosis and neurologic outcome of critically ill patients with VZV encephalitis are limited. We aimed to describe the clinical features of VZV encephalitis in the ICU and to identify factors associated with a favorable neurologic outcome. We performed a multicenter cohort study of patients with VZV encephalitis admitted in 18 ICUs in France between 2000 and 2017. Factors associated with a favorable neurologic outcome, defined by a modified Rankin Score (mRS) of 0-2 1 year after ICU admission, were identified by multivariable regression analysis.

Fifty-five patients (29 (53%) men, median age 53 (interquartile range 36-66)) were included, of whom 43 (78%) were immunocompromised. ICU admission occurred 1 (0-3) day after the onset of neurological symptoms. Median Glasgow Coma Score at ICU admission was 12 (7-14). Cerebrospinal fluid examination displayed a median leukocyte count of 68 (13-129)/mm³, and a median protein level of 1.37 (0.77-3.67) g/L. CT scan and MRI revealed brain lesions in 30% and 66% of the cases, respectively. Invasive mechanical ventilation was implemented in 46 (84%) patients for a median duration of 13 (3-30) days. Fourteen (25%) patients died in the ICU. One year after ICU admission, 20 (36%) patients had a favorable neurologic outcome (mRS 0-2), 12 (22%) had significant disability (mRS 3-5), and 18 (33%) were deceased (lost to follow-up n = 5, 9%). On multivariable analysis, age (OR 0.92 per year, (0.88-0.97), p = 0.01), and invasive mechanical ventilation (OR 0.09 CI 95% (0.01-0.84), p = 0.03) reduced the likelihood of favorable neurologic outcome.

One in every three critically ill patients with VZV encephalitis had a favorable neurologic outcome 1 year after ICU admission. Older age and invasive mechanical ventilation were associated with a higher risk of disability and death.