Necrotizing cerebellitis and cerebellar atrophy caused by Neospora caninum infection: magnetic resonance imaging and clinicopathologic findings in seven dogs.

BACKGROUND

Adult dogs with neosporosis can develop a variety of neurologic signs. No area of predilection within the nervous system so far has been identified in adult dogs.

OBJECTIVES

To document neosporosis as a cause of progressive cerebellar ataxia and cerebellar atrophy in dogs.

ANIMALS

Seven client-owned dogs.

METHODS

Retrospective, descriptive study.

RESULTS

Age at diagnosis ranged from 1 year 6 months to 9 years 11 months. Neuroanatomic localization indicated cerebellar and brainstem disease in 6 dogs and a central vestibular lesion in 1 dog. In all 7 dogs, there was moderate to marked bilaterally symmetrical cerebellar atrophy, with the atrophied cerebellum being surrounded by a region of T2-weighted hyperintense and T1-weighted hypointense signal. Cerebrospinal fluid (CSF) analysis in all but 1 dog showed mononuclear pleocytosis and high protein concentration. Polymerase chain reaction testing for Neospora caninum performed on the CSF was positive in 4/5 dogs tested and there was a high titer of serum antibodies to N. caninum (> or = 1 : 800) in all 6 dogs tested. Postmortem examination in 1 dog confirmed cerebellar atrophy and multifocal nonsuppurative encephalitis with areas of malacia and leptomeningitis. All of the remaining 6 dogs were treated with some combination of clindamycin, trimethoprim, sulfadiazine, and pyrimethamine. Two dogs were euthanized because of deterioration or relapse of neurologic signs, but treatment of the remaining 4 dogs resulted in improvement (3 dogs) or resolution (1 dog) of neurologic signs.

CONCLUSIONS AND CLINICAL IMPORTANCE

Neosporosis is an important cause of progressive cerebellar ataxia and cerebellar atrophy in adult dogs.