Canine cauda equina neuritis secondary to neospora

Abstract

A five-year-old, female spayed, crossbreed dog was presented for lethargy, fever, hyporexia and right hindlimb lameness of two weeks’ duration. Examination revealed an intermittent weightbearing right hindlimb lameness with delayed proprioceptive reflexes. When the right hindlimb was placed, weightbearing was through the dorsal pes. The other limbs were neurologically normal. The neurological deficits localised to L6–S2. CT and myelogram revealed focal nerve root enlargement with contrast enhancement of L7–S1 nerve roots. Neospora caninum neuritis was diagnosed by rising serum titres, along with a neutrophilic pleocytosis on cerebrospinal fluid. The dog showed clinical improvement with prednisone, clindamycin and trimethoprim/sulfadiazine but relapsed six months after cessation of treatment with similar presentation. The same treatment was initiated, and a positive response was seen again. There is only one other case of focal cauda equina neuritis secondary to Neospora reported in the literature and the response to treatment is not well documented.

Lumbosacral MRI findings in two dogs diagnosed with a Neospora caninum infection

“…To date, the published data concentrate primarily on multifocal meningoencephalitis, 8 necrotising cerebellitis 6,7 and cervical myelitis/myositis 10,11 . Previously, as mentioned earlier, thickening and contrast enhancement of the L7–S1 nerve roots without visible muscular change in a dog affected by N. caninum has been reported on CT images 3 . The relative usefulness of CT versus MRI in the identification of muscular changes has not been assessed in dogs; however, when identifying focal myopathies in people, MRI has been shown to be the more sensitive imaging modality 12 .…”

“…10,11 Previously, as mentioned earlier, thickening and contrast enhancement of the L7-S1 nerve roots without visible muscular change in a dog affected by N. caninum has been reported on CT images. 3 The relative usefulness of CT versus MRI in the identification of muscular changes has not been assessed in dogs; however, when identifying focal myopathies in people, MRI has been shown to be the more sensitive imaging modality. 12 Our case report highlights the presence of muscular changes associated with N. caninum in the lumbosacral area and the MRI findings of meningomyelitis and multifocal radiculoneuritis, which have not been reported in this region before, filling a gap in the literature and providing a more robust indication to perform targeted muscle biopsy of affected areas in these cases.…”

“…The polyradiculoneuritis‐myositis form of neosporosis typically presents with progressive hindlimb paresis (often with a bunny‐hopping gait reported) in dogs younger than 6 months of age 2 . The computed tomography (CT) findings for a case of lumbar polyradiculoneuritis caused by N. caninum in a puppy have been previously reported, revealing thickening and contrast enhancement of the right L7–S1 nerve roots and enlargement of the right medial iliac and colic lymph nodes 3 . In people, magnetic resonance imaging (MRI) is considered the gold standard in identifying muscular changes consistent with myopathy, although the nature of myopathy should be determined via histopathological examination 4 .…”

“…2 The computed tomography (CT) findings for a case of lumbar polyradiculoneuritis caused by N. caninum in a puppy have been previously reported, revealing thickening and contrast enhancement of the right L7-S1 nerve roots and enlargement of the right medial iliac and colic lymph nodes. 3 In people, magnetic resonance imaging (MRI) is considered the gold standard in identifying muscular changes consistent with myopathy, although the nature of myopathy should be determined via histopathological examination. 4 Given N. caninum's tendency to affect the muscle of affected animals, 5 using an imaging modality with the highest sensitivity for the detection of myopathy, with the view of sampling an affected area, would seem the logical choice for obtaining a definitive diagnosis ante-mortem.…”