Infectious encephalitis in elderly patients: a prospective multicentre observational study in France 2016–2019

Abstract

Purpose. Data on encephalitis in the elderly remain scarce. We aimed to describe the characteristics, aetiologies, management, and outcome of encephalitis in patients older than 65 years. Methods.We performed an ancillary study of ENCEIF, a prospective cohort that enrolled all cases of encephalitis managed in 46 clinical sites in France during years 2016-2019. Cases were categorized in 3 age groups: i) 18-64; ii) 65-79; iii) ≥80 years.Results. Of the 494 adults with encephalitis enrolled, 258 (52%) were ≥65 years, including 74 (15%) ≥80 years. Patients ≥65 years were more likely to present with coma, impaired consciousness, confusion, aphasia, and rash, but less likely to present with fever, and headache (P<0.05 for each). Median cerebrospinal fluid (CSF) white cells count was 61/mm 3 [13-220] in 65-79 years, 62 [17-180] in ≥80 years, vs. 114 [34-302] in <65 years (P=0.01). The proportion of cases due to Listeria monocytogenes and VZV increased after 65 years (P<0.001), while the proportion of tick-borne encephalitis and Mycobacterium tuberculosis decreased with age (P<0.05 for each).In-hospital mortality was 6/234 (3%) in <65 years, 18/183 (10%) in 65-79 years, and 13/73 (18%) in ≥80 years (P<0.001). Age ≥80 years, coma on admission, CSF protein ≥0.8 g/L and viral encephalitis were independently predictive of 6-month mortality. Conclusion.The elderlies represent >50% of adult patients with encephalitis in France, with higher proportion of L. monocytogenes and VZV encephalitis, increased risk of death, and sequels. The empirical treatment currently recommended, aciclovir and amoxicillin, is appropriate for this age group.

Predictors of mortality and poor outcome for patients with severe infectious encephalitis in the intensive care unit: a cross-sectional study

“…Additionally, it was found to cause persistent neurological symptoms upon discharge, particularly movement disorders [ 26 ]. A prospective multicentre observational study has shown that viral encephalitis independently predicts 6-month mortality [ 27 ]. This is different from our findings and may be related to the fact that the proportion of encephalitis caused by L. monocytogenes and VZV increased with age, the latter becoming the main cause of infectious encephalitis after 80 years of age, and the proportion of TBE and M. tuberculosis encephalitis decreased with age [ 27 ].…”