Reversible subacute secondary parkinsonism due to neuroborreliosis with characteristic MRI evolution.

A man in his 70s presented with a subacute akinetic-rigid syndrome consistent with secondary parkinsonism, characterised by axial rigidity, bradykinesia, hypophonia, gait initiation failure and constitutional symptoms. MRI demonstrated symmetrical T2/FLAIR hyperintensities involving the brainstem, diencephalon and dentate nuclei. Cerebrospinal fluid (CSF) showed lymphocytic pleocytosis, markedly elevated protein and low glucose, together with increased CXCL13 levels (exact quantitative value unavailable from the external laboratory report). Serum Borrelia IgG was positive and confirmed by western blot. No alternative infectious, autoimmune or neoplastic aetiology was identified. The overall picture supported a diagnosis of probable late neuroborreliosis according to EFNS criteria. Treatment with intravenous ceftriaxone followed by oral doxycycline resulted in rapid improvement. At 6-month follow-up, he was clinically asymptomatic and brain MRI demonstrated complete radiological resolution. This case highlights neuroborreliosis as an uncommon but reversible cause of secondary parkinsonism/parkinsonism mimic and underscores the diagnostic relevance of its distinctive imaging pattern.