Chronic lymphomonocytic meningoencephalitis, oligoarthritis and erythema nodosum: report of Baggio-Yoshinari syndrome of long and relapsing evolution.

The Brazilian human borreliosis, also known as Baggio-Yoshinari Syndrome (BYS), is a tickborne disease but whose ticks do not pertain to the Ixodes ricinus complex. It is caused by Borrelia burgdorferi sensu lato microorganisms and resembles clinical and laboratory features of Lyme disease (LD). BYS is also distinguished from LD by its prolonged clinical evolution, with relapsing episodes and autoimmune dysfunction. We describe the case of a young female who, over one year, progressively presented with oligoarthritis, cognitive impairment, menigoencephalitis and erythema nodosum. Diagnosis was established by means of the clinical history and a positive serology to Borrelia burgdorferi sensu strictu. The patient received Ceftriaxone 2 g IV/day during 30 days, followed by 2 months of doxicycline 100 mg bid. Symptoms remitted and the Borrelia serology tests returned to normality. BYS is a new disease described only in Brazil, which has a raising frequency and deserves the attention from the country´s medical board because of clinical, epidemiological and laboratory differences from LD. Despite the fact that it is a hard-to-diagnose zoonosis, it is important to pursuit an early diagnosis because the symptoms respond well to antibiotics or it might be resistant to treatment and may evolve to a chronic phase with both articular and neurological sequelae.