CNS INFLAMMATORY DISORDERS: INFECTIOUS DISEASES: Edited by Erich SchmutzhardNeurosyphilis and Lyme neuroborreliosisDersch, Ricka; Singh, Ameeta E.bAuthor Information aClinic of Neurology and Neurophysiology, Medical Center University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany bDivision of Infectious Diseases, Department of Medicine, University of Alberta, Edmonton, Canada Correspondence to Dr Rick Dersch, Clinic of Neurology and Neurophysiology, Medical Center University of Freiburg, Breisacher Str. 64, 79106 Freiburg, Germany. Tel: +49 (0)761 270 50010; e-mail: [email protected] Current Opinion in Neurology: June 2021 - Volume 34 - Issue 3 - p 403-409 doi: 10.1097/WCO.0000000000000923 Buy Metrics Abstract Purpose of review Neurosyphilis (NS) and Lyme neuroborreliosis (LNB) are spirochetal diseases with distinct clinical manifestations. The diagnosis of NS remains challenging due to imperfect diagnostic criteria and testing modalities. With LNB, misconceptions about diagnosis and treatment lead to considerable morbidity and drug related adverse effects. Recent findings Although studies continue investigating alternate approaches and new diagnostic tests for NS, few data exist to change current approaches to diagnosis, management or follow up. In the diagnosis of LNB, the chemokine CXCL13 shows promising diagnostic accuracy. A systematic review discourages the use of cell-based assays when investigating Lyme disease. Clinical studies show no benefit from extended antibiotic treatment for patients with unspecific symptoms labelled as having Lyme disease. Summary The diagnosis of NS may be delayed due to a lack of specificity of findings, low suspicion for syphilis, and/or similarities in presentation to other diseases. A high index of suspicion for syphilis is required provide timely diagnosis and management of NS. Fortunately, penicillin remains the treatment of choice. Overdiagnosis and overtreatment in patients labelled as having Lyme disease can be avoided by an evidence-based approach towards diagnosis and treatment. Copyright © 2021 Wolters Kluwer Health, Inc. All rights reserved.