Lyme neuroborreliosis (LNB) presents with a broad range of symptoms and its incidence is increasing in Finland. This study examines clinical differences in LNB between adults and children (< 16 years), emphasizing head and neck symptoms, the prognostic value of laboratory tests, the findings in brain MRI, and the impact of glucocorticoids on facial palsy (FP) recovery.

A retrospective analysis of LNB cases at Turku University Hospital (2011–2018) confirmed by intrathecal antibody production against Borrelia was conducted. With regard to cerebrospinal fluid pleocytosis, LNB was further classified as definite or possible. Patient characteristics were compared using appropriate statistical tests.

In total 159 adult and 25 child LNB patients were found. The most common symptom in adults was radiculitis (37% vs. 8%, p = 0.03), while in children, it was FP (76% vs. 46%, p = 0.0052). In children, the absence of FP was linked to delayed diagnosis (5.5 ± 9.1 weeks vs. 0.97 ± 0.92 weeks p = 0.043). Of the pediatric LNB patients, 68% were seropositive for antibodies against Borrelia based on serum samples. Cranial nerve enhancement was observed in 26% of brain MRIs in the study cohort. No link between CSF findings or corticosteroid treatment and persisting FP was found.

In adults, the most common manifestation related to LNB was radiculitis, whereas in children it was FP. One third of the pediatric patients were seronegative for antibodies against Borrelia, emphasizing the importance of CSF analysis in the diagnosis of LNB. Corticosteroids did not affect the recovery from FP and CSF findings had no prognostic value on recovery from FP.