Normal pressure hydrocephalus or neuroborreliosis?

BACKGROUND: An 80-year-old woman presented with progressive cognitive decline and with a 6-month history of gait ataxia. Brain MRI depicted enlarged ventricles and periventricular lesions. Clinical improvement after CSF spinal tap test suggested a normal pressure hydrocephalus syndrome. But CSF pleocytosis with activated lymphocytes and plasma cells and intrathecal Borrelia burgdorferi specific antibody production led to the diagnosis of active Lyme neuroborreliosis. Clinical symptoms of NPH resolved after a course of ceftriaxone. METHODS: Neurological examination, MMSE, brain MRI, lumbar puncture, spinal tap test. RESULTS: Dementia due Borrelia burgdorferi infection with chronic meningitis was reversible after treatment with iv.2 g ceftriaxone per day for 4 weeks. CONCLUSIONS: Rare but treatable dementias must be diagnosed promptly to slow down or even reverse cognitive decline.