Central Nervous System Vasculitis Due to Ehrlichia canis in a Dog

A 4-year-old female neutered crossbreed dog was presented for a 2-month history of intermittent vestibulo-cerebellar ataxia and right head tilt. On admission, she presented clinical signs compatible with right paradoxical vestibular syndrome. Haematology showed moderate lymphocytosis, thrombocytopenia and hyperproteinaemia with hyperglobulinemia. Magnetic resonance imaging of the brain showed multiple, bilateral, ill-defined lesions involving the white matter of the brainstem, cerebellum and forebrain with strong diffuse meningeal contrast enhancement. Cerebrospinal fluid cytology showed lymphocytic pleocytosis, and Ehrlichia spp. serology was positive. Treatment with doxycycline showed clinical improvement within 24 h, treatment was continued for 6 weeks. A follow-up magnetic resonance imaging study was performed after treatment and showed complete resolution of the previous lesions. Cerebrospinal fluid analysis showed only albumin-cytological dissociation. Since treatment initiation, the patient remained asymptomatic. Three months after hospital discharge, no further episodes were reported.