Lyme neuroborreliosis epidemiology in Sweden 2010 to 2014: clinical microbiology laboratories are a better data source than the hospital discharge diagnosis register

Abstract

Background In a study from 2013 that prioritised communicable diseases for surveillance in Sweden, we identified Lyme borreliosis as one of the diseases with highest priority. In 2014, when the present study was designed, there were also plans to make neuroborreliosis notifiable within the European Union. Aim We compared possibilities of surveillance of neuroborreliosis in Sweden through two different sources: the hospital discharge register and reporting from the clinical microbiology laboratories. Methods We examined the validity of ICD-10 codes in the hospital discharge register by extracting personal identification numbers for all cases of neuroborreliosis, defined by a positive cerebrospinal fluid–serum anti- Borrelia antibody index, who were diagnosed at the largest clinical microbiology laboratory in Sweden during 2014. We conducted a retrospective observational study with a questionnaire sent to all clinical microbiology laboratories in Sweden requesting information on yearly number of cases, age group and sex for the period 2010 to 2014. Results Among 150 neuroborreliosis cases, 67 (45%) had received the ICD-10 code A69.2 (Lyme borreliosis) in combination with G01.9 (meningitis in bacterial diseases classified elsewhere), the combination that the Swedish National Board of Health and Welfare recommends for neuroborreliosis. All 22 clinical laboratories replied to our questionnaire. Based on laboratory reporting, the annual incidence of neuroborreliosis in Sweden was 6.3 cases per 100,000 in 2014. Conclusion The hospital discharge register was unsuitable for surveillance of neuroborreliosis, whereas laboratory-based reporting was a feasible alternative. In 2018, the European Commission included Lyme neuroborreliosis on the list of diseases under epidemiological surveillance.

Neutrophil Extracellular Traps (NETs) in the Cerebrospinal Fluid Samples from Children and Adults with Central Nervous System Infections

“…Lyme neuroborreliosis (LNB), which is caused by a complex of Gram-negative spirochaetes called Borrelia burgdorferi sensu lato and transmitted to humans by the Ixodes ricinus tick, is the most serious manifestation of Lyme disease (LD) [1]. Borrelia constitutes a common cause of bacterial infection of the central nervous system (CNS) among children and adults in Sweden [2][3][4][5] and Finland [6]. According to the diagnostic criteria for LNB [7], mononuclear pleocytosis must be present in the cerebrospinal fluid (CSF), and this is an indicator of an active infection.…”

­­Lyme borreliosis in Finland: A register-based linkage study

“…These cases probably represent true LB cases where the physicians missed entering ICD-10 code for LB to the patient records. Similarly, a recently published Swedish study found that less than half of all microbiologically confirmed LNB patients received the recommended combination of ICD-10 codes for LNB and only two thirds of the patients received the code for LB at all (13).…”

“…However, the comparison of actual, national incidence rates among countries is difficult due to lack of uniform and standardized diagnostic methods, case definitions, reporting practices, and surveillance systems. Only some European countries have a mandatory notification system for LB (7,8,(11)(12)(13). In those countries, LB surveillance is mostly based on laboratory surveillance resulting in that the clinically diagnosed EM is greatly neglected.…”

“…In the recently published study from Norway, the antibody testing was performed in ~ 20.0% of GP diagnosed EM cases(19).Next to laboratory-based reporting of LB, the inclusion of EM as another key indicator has been suggested to LB surveillance in Europe(20,21). Some European countries have estimated the incidence of LB and the frequency of its different manifestations through repeated cross-sectional physician surveys or through register-based studies monitoring of notified in-and outpatient diagnoses(9,13,14, 16,22). In these studies, the provided EM incidence estimates rarely represent the whole country or all the physicians involved in the diagnostics and treatment of LB within the country.…”

Lyme Neuroborreliosis in a Patient with Breast Cancer: MRI and PET/CT Findings

“…As illustrated within this case, only 25% and 50% recall a previous tick bite or erythema migrans, respectively, when they present with Lyme neuroborreliosis [2]. With an estimated prevalence of 3-120 per 100,000 inhabitants in Scandinavia, Lyme neuroborreliosis is one of the most prevalent bacterial infections of the nervous system [3,4]. The diagnosis of Lyme neuroborreliosis depends on classical symptoms including radicular pain and paralysis (typically facial paralysis), elevated white blood cells in CSF and the presence of intrathecal B. burgdorferi antibody production.…”