Purpose of review: To review the recent evidence clarifying the symptomatology and diagnosis of nervous system Lyme disease.
Recent findings: Two-tier testing combining pairs of ELISAs, using C6 or VlsE assays to replace second tier Western blots, may eliminate confusion about test interpretation. Cerebrospinal fluid (CSF) can be informative in diagnosing central nervous system (CNS) Lyme disease, not peripheral nervous system (PNS) disorders. CSF CXCL13 may provide useful adjunctive information in CNS infection; its specificity remains to be defined. Lyme encephalopathy is not indicative of CNS infection. Post treatment Lyme disease symptoms do not occur in patients who have had definite CNS Lyme infection. Whether post treatment Lyme disease symptom (PTLDS) is an actual entity, or reflects anchoring bias when commonly occurring symptoms arise in patients previously treated for Lyme disease, remains to be determined. Regardless, these symptoms do not reflect CNS infection and do not respond to additional antimicrobial therapy.
Summary: Serologic testing is robust in individuals with a priori likelihood of infection of greater than 2-6 weeks duration. Western blots provide useful confirmation of screening ELISAs, but may be replaced by second ELISAs. CSF testing, including CXCL13, may be informative in CNS Lyme, not PNS, and is generally normal in Lyme encephalopathy. PTLDS does not occur following CNS infection, and may not be a distinct entity.