Central nervous system infections

Abstract

Central nervous system (CNS) infections occur in up to 15 % of hematology patients, particularly after allogeneic stem cell transplantation (AlloSCT) or in conjunction with neutropenia. The most frequent causative organisms after AlloSCT areAspergillusspp. AndToxoplasma gondii, which typically cause focal parenchymatous lesions like abscesses or strokes. Meningoencephalitis is less common in these patients and might be related to viruses (mainly human herpesvirus-6 (HHV-6)) but sometimes also to fungi (e.g., Candidaspp., Cryptococcus neoformans) or bacteria (e.g., Staphylococcus aureus, coagulase-negativeStaphylococcusspp.). Definitive diagnosis of CNS infections, though still often made only at autopsy, is crucial and relies mainly on neuroimaging, cerebrospinal fluid (CSF) analysis, and/or stereotactic biopsy of focal lesions. Empirical or preemptive anti-infective drug therapy should be prompted immediately after obtaining CSF and/or biopsy tissue and adjusted after identifying a causative agent and determining its in vitro susceptibility. CNS infections in hematology patients are still largely associated with a poor prognosis and a mortality rate of up to 90 %. However, particularly the introduction of new antifungal agents with improved pharmacological profiles has led to better outcomes in selected subgroups of patients such as those with CNS aspergillosis.