Computed Tomography of Necrotizing Meningoencephalitis in 3 Yorkshire Terriers

Abstract

A necrotizing meningoencephalitis of Yorkshire terriers has recently been reported in 6 dogs in Switzerland, 1 dog in Japan and 1 dog in the United States. The purpose of this report is to describe the computed tomographic (CT) findings in 3 dogs with this disease, and to correlate the CT abnormalities with the clinical and pathologic findings in each case. Three Yorkshire Terriers between 2 and 10 years old were evaluated. Physical and neurologic examinations, complete blood count (CBC), serum biochemistry profile, cerebrospinal fluid analysis, and CT scan were performed on all 3 dogs. Brainstem auditory evoked responses (BAER) were evaluated for 2 dogs. Two dogs were euthanized at the owners' request and necropsies were performed. Neurologic examination findings were consistent with a multifocal/diffuse encephalitis involving the cerebrum and brainstem in all 3 dogs. Complete blood count and biochemistry profiles were normal. Elevated protein concentration and a mononuclear pleocytosis were demonstrated in 2 of 3 dogs on cerebrospinal fluid evaluation. Multifocal, extensive areas of decreased opacity throughout the cerebral hemispheres, asymmetric ventriculomegaly, and lack of contrast enhancement were appreciated on CT images of all three dogs. No mass effect was seen. These findings correlated well with pathologic findings at necropsy, which included multiple malacic cavitations within the brain, representing areas of locally extensive necrosis. CT abnormalities in combination with signalment, clinical findings and cerebrospinal fluid analysis should facilitate a presumptive diagnosis of Yorkshire Terrier necrotizing meningoencephalitis.

Prevalence of Autoantibody in Cerebrospinal Fluids from Dogs with Various CNS Diseases

“…NME was diagnosed in 9 Pugs, 6 Pomeranians, 2 Malteses, 2 Yorkshire Terriers, 1 Shih-Tzu, 1 Pekingese and 1 Chihuahua (total n=22). These breeds in our experience well matched to those in previous articles [2,3,5,9,16,17] with an exception, Pomeranian. All NME cases possessed the anti-astrocyte autoantibody with titers ranging from 1:1 to ≥1:100.…”

“…Necrotizing meningoencephalitis (NME: Pug encephalitis) has been reported sporadically in young Pugs [3,9,17] and other small-breeds [2,5,16] presenting progressive neurological abnormalities such as seizures, ataxia and dementia. Histopathology is characterized by parenchymal necrosis, severe infiltration of mononuclear cells and glial satellitosis in the cerebrum, especially in the subleptomeningeal area.…”

Necrotizing Meningoencephalitis in Atypical Dog Breeds: A Case Series and Literature Review

“…Seizure activity is the most commonly reported neurological sign in dogs with NME,5, 11 whereas brainstem signs (along with seizure activity) are more commonly described in dogs with NLE 17, 18, 19, 20, 21. In 2 of 4 dogs, clinical signs reflecting a caudal brainstem component to a multifocal neuroanatomical localization (eg, ataxia and nausea) were observed.…”

Comprehensive Immunohistochemical Studies on Canine Necrotizing Meningoencephalitis (NME), Necrotizing Leukoencephalitis (NLE), and Granulomatous Meningoencephalomyelitis (GME)

“…CD3-positive T cells in the perivascular cuffs, neuroparenchyma, and leptomeningeal lesions were predominant among the inflammatory cell populations in the order of GME, NLE, and NME, and the proportions of these cells were significantly different between the diseases (Figs. 13,16,19,22). However, there were few CD3-positive T cells in the malacic regions of NME and NLE.…”