Neuroborreliosis at the region of Asturias, Spain (2009-2022): Analysis of 38 cases.

Introduction: Diagnosis of neurological involvement in Lyme disease is based on two-step serological testing and cerebrospinal fluid pleocytosis. In Spain its incidence is much lower than in other European countries, being Asturias the region with the highest incidence. We tried to analyse the clinical and epidemiological aspects in the main hospital in Asturias.

Material y methods: Retrospective observational study of patients admitted for Lyme disease in our center over 14years (2009-2022). Clinical, analytical and evolutionary variables were analyzed after one year. Active neuroborreliosis was diagnosed after registering pleocytosis and positive serologies at the cerebrospinal fluid.

Results: 108 episodes were analyzed, corresponding to 100 patients coded at discharge as Lyme disease. 58 episodes are discarded due to diagnostic or coding error. 51 episodes were considered active disease, being 38 diagnosed of neuroborreliosis. Tick bite recall and erythema were reported in 55.3% and 31.6% of patients. The most frequent neurological syndromes were radiculoneuritis (36.84%), bilateral facial palsy (13.56%), radiculoneuritis and bilateral facial palsy (10.52%) and multiple cranial mononeuropathy (10.52%), among others. 78.9% achieved a complete recovery, and 15.79% developed post-treatment Lyme disease syndrome.

Discussion: Despite the high incidence of Lyme disease in Asturias, the cases based on hospital admission that can be classified as active disease are lower than those published based on hospital coding. The main source of diagnostic error is positive serological results, without other clinical context, especially in patients studied for cognitive impairment or encephalopathy.