Intradural Dirofilariasis in a Dog with Chronic Cervical Pain

A 7 yr old female spayed Yorkshire terrier was referred to the author's institute for a 5 mo history of recurrent cervical spinal pain. Neurologic examination did not reveal any deficits. Hematologic and serum analyses were within normal limits. Thoracic radiographs that incorporated the cervical spine did not show structural abnormalities. Magnetic resonance imaging of the cervical spine demonstrated a contrast enhancing, intradural extramedullary lesion at the level of the C2 vertebra. Hemilaminectomy was performed, during which a long, narrow nematode was visualized upon opening of the dura mater. The parasite was alive when removed during surgery, and the dog recovered with complete resolution of symptoms. The parasite was submitted and confirmed as a male adult Dirofilaria immitis. This is a novel case of an intradural D. immitis infection in the dog with a magnetic resonance imaging description of spinal D. immitis.