Background: Bell's palsy and Lyme neuroborreliosis are the two most common diagnoses in patients with peripheral facial palsy in areas endemic for Borrelia burgdorferi. Bell's palsy is treated with corticosteroids, while Lyme neuroborreliosis is treated with antibiotics. The diagnosis of Lyme neuroborreliosis relies on the detection of Borrelia antibodies in blood and/or cerebrospinal fluid, which is time consuming. In this study, we retrospectively analysed clinical and cerebrospinal fluid parameters in well-characterised patient material with peripheral facial palsy caused by Lyme neuroborreliosis or Bell's palsy, in order to obtain a working diagnosis and basis for treatment decisions in the acute stage.
Methods: Hospital records from the Department of Infectious Diseases, Sahlgrenska University Hospital, for patients with peripheral facial palsy that had undergone lumbar puncture, were reviewed. Patients were classified as Bell's palsy, definite Lyme neuroborreliosis, or possible Lyme neuroborreliosis, on the basis of the presence of Borrelia antibodies in serum and cerebrospinal fluid and preceding erythema migrans.
Results: One hundred and two patients were analysed; 51 were classified as Bell's palsy, 34 as definite Lyme neuroborreliosis and 17 as possible Lyme neuroborreliosis. Patients with definite Lyme neuroborreliosis fell ill during the second half of the year, with a peak in August, whereas patients with Bell's palsy fell ill in a more evenly distributed manner over the year. Patients with definite Lyme neuroborreliosis had significantly more neurological symptoms outside the paretic area of the face and significantly higher levels of mononuclear cells and albumin in their cerebrospinal fluid. A reported history of tick bite was uncommon in both groups.
Conclusions: We found that the time of the year, associated neurological symptoms and mononuclear pleocytosis were strong predictive factors for Lyme neuroborreliosis as a cause of peripheral facial palsy in an area endemic for Borrelia. For these patients, we suggest that ex juvantibus treatment with oral doxycycline should be preferred to early corticosteroid treatment.