Retrospective Study Evaluating Associations Between Midline Brain Shift on Magnetic Resonance Imaging and Survival in Dogs Diagnosed With Meningoencephalitis of Unknown Etiology

Abstract

Difficulty has been encountered when trying to identify ante mortem prognostic indicators for dogs with meningoencephalitis of unknown etiology (MUE). Identifying MRI imaging parameters associated with prognosis may impact treatment decision-making for clinician and owner. Our hypotheses for this retrospective cohort study are that dogs diagnosed with MUE that had midline shift on brain MRI would have a poorer survival compared to dogs without midline shift; and that younger age, lower weight, and low cerebrospinal fluid (CSF) cell count would be correlated with improved survival. Medical records were reviewed from two institutions. Inclusion criteria included: clinical signs referable to intracranial disease, brain MRI at presentation, abnormal CSF analysis, and negative infectious disease testing. Magnetic resonance imaging scans were evaluated for midline shift using the T2-weighted transverse image at the interthalamic adhesion and at the site of maximal deviation. Fifty-two dogs met the inclusion criteria. Median midline deviation was 0.12 cm. Median survival for dogs with no shift was 906 days and with shift was 84 days. Survival was not significantly different between groups (P = 0.11). This remained true when correcting for age (P = 0.22) and CSF TNCC (total nucleated cell count) (P = 0.12). Age at the time of diagnosis (P = 0.02) and CSF TNCC (P = 0.03) were significantly associated with survival. Cerebrospinal fluid protein value (P = 0.84) and weight (P = 0.82) were not significantly associated with survival. In this study of 52 dogs with MUE, MRI evidence of midline brain shift between 0.04 and 0.3 cm at the level of the interthalamic adhesion was not associated with shorter survival.

Development of a reliable clinical assessment tool for meningoencephalitis in dogs: The neurodisability scale

“…Meningoencephalitis of unknown origin in dogs is a debilitating disease and, despite appropriate treatment, 25% to 33% of dogs die within a week of diagnosis 5,6 . Several studies have evaluated short and long‐term outcome in dogs with MUO, but all have focused on survival at different time points 5‐14 . The use of survival as an outcome measure for MUO patients is flawed because affected dogs often are euthanized, and owners may elect for euthanasia at different time points based on a variety of complex underlying factors including financial constraints, difficulties managing chronic disease and views on what constitutes acceptable quality of life.…”

Prognostic Factors for Recovery of Vision in Canine Optic Neuritis of Unknown Etiology: 26 Dogs (2003–2018)

“…The younger the dog was at presentation the higher were the chances for complete recovery of vision in this study population. Similarly, a recent publication investigating canine MUE showed that younger age at onset was associated with longer survival, but none of these dogs were diagnosed with concurrent ON (58). Still, other authors failed to repeat this finding (11, 57).…”

“…Similar to our findings (Table 2), this study reported that the CSF TNCC was significantly higher in dogs with MUE-ON (median = 146 cells/μl) than in those with I-ON (median = five cells/μl) (5). In canine MUE, a higher CSF TNCC was associated with shorter survival (58), whereas this finding was dismissed by an earlier study (11). In people, the presence of CSF pleocytosis is not a pathognomonic feature of specific ON subtypes, but a greater pleocytosis is expected with NMO than MS (111–113).…”

Immune-Mediated Central Nervous System Disease—Current Knowledge and Recommendations

“…42 Another study evaluating the association between midline shift on MRI and survival time also found that the degree and presence of a midline shift did not correlate with a shorter survival time. 41…”

“…Multiple studies have found that the CSF total nucleated cell count does not correlate with prognosis 1,43,44 ; however, one study did show that a higher total nucleated cell count (TNCC) was associated with a worse prognosis. 41…”