Ticking the right boxes: classification of patients suspected of Lyme borreliosis at an academic referral center in the Netherlands.

To provide better care for patients suspected of having Lyme borreliosis (LB) we founded the Amsterdam Multidisciplinary Lyme borreliosis Center (AMLC). The AMLC reflects a collaborative effort of the departments of internal medicine/infectious diseases, rheumatology, neurology, dermatology, medical microbiology and psychiatry. In a retrospective case series, characteristics of 200 adult patients referred to the AMLC were recorded, and patients were classified as having LB, post-treatment LB syndrome (PTLBS), persistent Borrelia burgdorferi sensu lato (s.l.) infection despite antibiotic treatment or no LB. In addition, LB, PTLBS and persistent B. burgdorferi s.l. infection cases were classified as 'definite,' 'probable' or 'questionable.' Of the 200 patients, 120 (60%) did not have LB and 31 (16%) had a form of localized or disseminated LB, of which 12 were classified as definite, six as probable and 13 as questionable. In addition, 34 patients (17%) were diagnosed with PTLBS, of which 22 (11%) were probable and 12 (6%) questionable. A total of 15 patients (8%) were diagnosed with persistent B. burgdorferi s.l. infection, of which none was classified as definite, three as probable and 12 as questionable. In conclusion, in line with previous studies, the number of definite and probable (persisting) LB cases was low. The overall high number of questionable cases illustrates the fact that it can sometimes be challenging to either rule out or demonstrate an association with a B. burgdorferi s.l. infection, even in an academic setting. Finally, we were able to establish alternative diagnoses in a large proportion of patients.