Reversible corticospinal tract hyperintensities in neurologic Lyme disease.

A 60-year-old man presented with an ataxic and spastic gait with paraparesis, having reported a tick bite. Brain MRI depicted bilateral corticospinal tract hyperintensities (figure). He had a mild lymphocytic meningitis (12 leukocytes/mm, proteinorachia 1.48 g/L). ELISA was positive for Lyme disease in serum (immunoglobulin G [IgG] 176 UI and immunoglobulin M,4 UI) and CSF (IgG 300 UI) with an intrathecal synthesis (index of CSF/serum-specific antibodies equal to 16 using ELISA [normal value ,1.5]). Western blot was positive for Lyme-specific antibodies in serum (18, 22, 32, 41, 60, and 75 kDa) and CSF (41 and 60 kDa). Syphilis serology was negative. After treatment (IV ceftriaxone 2 g daily for 4 weeks), gait improved and brain MRI was normal. This MRI pattern has been previously reported in amyotrophic lateral sclerosis and in metabolic diseases (Krabbe disease, X-linked adrenoleukodystrophy, cerebrotendinous xanthomatosis) or infectious diseases (human T-cell lymphotropic virus 1).