196 Dogs Studied: Differentiating NIME Subtypes in Canine CNS Disease

Canine Meningoencephalomyelitis Study Details 196 Cases

A multicenter retrospective study published by veter96.ru evaluated 196 dogs with histopathologically confirmed non-infectious meningoencephalomyelitis (NIME), providing new data on how clinicians can differentiate between the disease’s most common subtypes during a patient’s life. Among the evaluated dogs, 37 percent presented with granulomatous meningoencephalomyelitis (GME), while 34 percent had necrotizing encephalitis (NE). The remaining 29 percent of cases comprised other non-infectious inflammatory conditions of the central nervous system.

The research highlights that cerebrospinal fluid (CSF) leukocyte counts ran significantly higher in dogs diagnosed with GME. Specifically, a threshold of 208 leukocytes per microliter indicated GME with a sensitivity of 46.4 percent and a specificity of 78.5 percent. However, the predominant cell type found in CSF did not reliably correspond to a specific histopathological subtype, and no dog with analyzed CSF featured both completely normal magnetic resonance imaging (MRI) scans and normal CSF findings.

Combining MRI Features and Body Weight Improves Disease Differentiation

Differentiating dogs with necrotizing encephalitis from those with granulomatous meningoencephalomyelitis proved significantly more effective when veterinarians combined body weight, forebrain clinical signs, and specific MRI characteristics. Researchers observed that hypointense lesions on fluid-attenuated inversion recovery (FLAIR) images, alongside involvement of the cerebellum, brainstem, or spinal cord, yielded an area under the curve (AUC) of 0.823. Relying solely on body weight achieved a lower AUC of 0.710.

The study also cataloged various other non-infectious inflammatory diagnoses within the 29 percent non-GME, non-NE cohort. These included 25 cases of nonspecific lymphoplasmacytic meningoencephalomyelitis, eight cases of sterile neutrophilic meningoencephalomyelitis, seven cases linked to vasculitis, one eosinophilic case, six other sterile forms, and 10 cases that remained histologically undetermined.

Diagnostic Implications for Veterinary Practice

While definitive diagnosis of canine meningoencephalomyelitis typically requires tissue biopsy, the findings demonstrate that routine clinical parameters and MRI metrics can help identify underlying subtypes when histology is unavailable. The frequent overlap between clinical signs means veterinarians must evaluate complete diagnostics carefully. Because normal MRI and CSF results never occurred together in confirmed NIME patients, encountering either normal metric alone should prompt clinicians to reevaluate the diagnostic pathway.