BORRELIA-BURGDORFERI SEROPOSITIVE CHRONIC ENCEPHALOMYELOPATHY - LYME NEUROBORRELIOSIS - AN AUTOPSIED REPORT

A 36-year-old Japanese woman presented with progressive cerebellar sig ns and mental deterioration of subacute course after her return from t he USA. Her serum antibody to spirochete Borrelia burgdorferi was sign ificantly elevated. A necropsy 4 years after her initial neurological signs revealed multifocal inflammatory change in the cerebral cortex, thalamus, superior colliculus, dentate nucleus, inferior olivary nucle us and spinal cord. The lesions showed spongiform change, neuronal cel l loss, astrocytosis and proliferation of activated microglial cells. The internal capsule was partially vacuolated and the spinal cord, not ably at the thoracic level, was demyelinated and cavitated in the late ral funiculus. Microglial cells aggregated within and around the spong iform lesions and microglial nodules were present in the medulla oblon gata. Use of Warthin-Starry stain demonstrated silver-impregnated orga nisms strongly suggesting B. burgdorferi in the central nervous tissue s. The dentate nucleus and inferior olivary nucleus showed the most ad vanced lesions with profound fibrillary gliosis. Occlusive vascular ch ange was relatively mild, and fibrous thickening of the leptomeninges with lymphocyte infiltrates was localized in the basal midbrain. The a taxic symptoms were due to the dentate and olivary nucleus lesions and mental deterioration was attributable to the cortical and thalamic le sions. Spongiform change, neuronal cell loss, and microglial activatio n are characteristic pathological features in the present case. The ce rebellar ataxia and subsequent mental deterioration are unusual clinic al features of Lyme neuroborreliosis. Spirochete B. burgdorferi can ca use focal inflammatory parenchymal change in the central nervous tissu es and the present case may be an encephalitic form of Lyme neuroborre liosis.