Lyme neuroborreliosis with encephalitis; a systematic literature review and a Scandinavian cohort study.

BACKGROUND

Lyme neuroborreliosis (LNB) presenting with encephalitis is rare and scarcely described.

OBJECTIVES

To describe the available literature on LNB encephalitis and to characterize this patient group through a Scandinavian retrospective cohort study.

DATA SOURCES

Medline, Embase, Scopus, Cochrane library.

STUDY ELIGIBILITY CRITERIA

There was no discrimination on study type, time of publication or language.

PARTICIPANTS

Review: All articles with definite LNB and confirmed/possible encephalitis.

COHORT

LNB cohorts from Denmark, Sweden and Norway 1990-2019 were screened for patients with encephalitis.

METHODS

Review: Adhering to PRISMA guidelines; two authors extracted reviews and assessed quality of studies.

COHORT

Data on demography, symptoms, cerebrospinal fluid findings, differential diagnostic examinations, treatment, residual symptoms, 1-year mortality were registered.

RESULTS

Review: 2330 articles screened on title/abstract, 281 full texts, yielding 42 articles (case reports/series or cohort studies), including 45 patients from 18 countries spanning 35 years. Altered mental status ranged from personality changes and confusion to unconsciousness. Common focal symptoms were hemiparesis, ataxia and dysarthria; seven patients had seizures. Median time from symptom onset to hospital was 2 weeks (IQR 2-90 days). Of 38 patients with available follow-up after median 12 months (IQR 5-13), 32 had fully or partially recovered, two had died.

COHORT

Thirty-five patients (median age 67 years, IQR 48-76) were included. The encephalitis prevalence was 3.3% (95% CI 2.2-4.4%) among 1019 screened LNB patients. Frequent encephalitis symptoms were confusion, personality changes, aphasia, ataxia. EEGs and neuroimaging showed encephalitis in 93.8% and 20.6%, respectively. Median delay from symptom onset to hospital was 14 days (IQR 7-34), with further 7 days (IQR 3-34) delay until targeted therapy. At follow-up (median 298 days post-treatment; IQR 113-389), 65.6% had residual symptoms. None had died.

CONCLUSIONS

This study shows that encephalitis is an uncommon, but likely overlooked clinical manifestation of LNB. As the high frequency of residual symptoms may be related to prolonged treatment delay, prompt LNB testing of patients with encephalitis in Borrelia burgdorferi-endemic areas should be considered.