Characteristics and Clinical Outcome of Lyme Neuroborreliosis in a High Endemic Area, 1995-2014: A Retrospective Cohort Study in Denmark

Background. Despite a well-described symptomatology, treatment delay and sequelae are common in patients with Lyme neuroborreliosis (LNB). The aim of this study was to contribute to the knowledge about the symptomatology and epidemiology of LNB. Methods. We conducted a retrospective study of all LNB cases verified by a positive Borrelia intrathecal antibody index test performed at the Department of Microbiology, Odense University Hospital, Denmark, from 1995 through 2014. Results. The study included 431 patients; 126 were children. The mean incidence was 4.7 per 100 000 inhabitants per year. The median delay from neurological symptom debut to first hospital contact was 20 days and significantly longer for patients with symptom debut in the winter/early spring. The most common clinical symptoms were painful radiculitis (65.9%), cranial nerve palsy (43.4%), and headache (28.3%). A total of 30.6% were seen in > 1 hospital department, and 85.6% were admitted during their course of treatment. Serum Borrelia immunoglobulin M and immunoglobulin G at the time of positive Borrelia intrathecal antibody index test were negative in 67 patients (15.5%). We found a median treatment delay of 24 days, with no improvement in our 20-year study period. Residual symptoms following treatment were found in 28.1% of patients, and risk of residual symptoms was significantly associated with delay from symptom debut to initiation of treatment. Conclusions. The association between treatment delay and residual symptoms and the lack of improvement in treatment delay during the study period highlight the need for standardized diagnostic routines and a better follow-up for LNB patients. Our findings disprove that all patients with LNB develop positive serum Borrelia antibodies within 6 weeks after infection.