Clinical features and outcomes of neuroleptospirosis in French Guiana: Insights from a retrospective study (2015–2021)

BACKGROUND: Leptospirosis is a re-emerging public health threat in French Guiana with a broad clinical spectrum. Neurological involvement (neuroleptospirosis) lacks a consensus definition and may be underrecognized. This study aimed to characterize its epidemiology, clinical features, outcomes, and associated factors. METHODS: A multicenter retrospective study was conducted across healthcare facilities in French Guiana from 2015 to 2021. Consecutive hospital-managed patients with laboratory-confirmed or probable leptospirosis were included. Neuroleptospirosis was defined by neurological symptoms combined with objective cerebrospinal fluid (CSF) and/or neuroimaging abnormalities. Patients with and without neurological involvement were compared. RESULTS: Among 146 patients, 18 (12%) met the criteria for neuroleptospirosis, corresponding to a mean annual incidence of 0.88 cases/100,000 inhabitants (95% CI 0.52-1.39). Presentations were meningeal (78% [14/18]), encephalitic (17% [3/18]) or meningoencephalitic (6% [1/18]). Lumbar puncture was performed in 28/146 (19%) patients; pleocytosis was observed in 18/28 (64%). The median CSF leukocyte count was 42 cells/mm3 (IQR, 13-240 cells/mm3), with lymphocytic predominance in 8/13 differential counts (62%). CSF protein was mildly elevated (median, 0.51 g/L; IQR, 0.32-0.88), without hypoglycorrhachia. Brain magnetic resonance imaging (MRI) revealed abnormalities in 2/8 patients with neuroleptospirosis: one cerebral infarction and one case of pachymeningitis. Age under 30 years (OR, 5.56; 95% CI 1.72-18), absence of leukocytosis during hospitalization (OR, 3.29; 95% CI 1.04-10.39), and absence of thrombocytopenia (OR, 4.46; 95% CI 1.39-14.32) were associated with neuroleptospirosis. Under our diagnostic criteria, neuroleptospirosis cases were associated with favorable outcomes, with lower odds of sepsis (OR, 0.28; 95% CI 0.10-0.79), no intensive care unit admissions or deaths. CONCLUSIONS: This study clarifies the clinical spectrum and outcomes of neuroleptospirosis in French Guiana, highlighting the importance of clinical awareness in tropical endemic settings. Prospective studies incorporating systematic CSF analysis and microbiological testing are needed to improve understanding of its pathophysiology and standardize diagnostic pathways.