RETROSPECTIVE STUDY EVALUATING ASSOCIATIONS BETWEEN MIDLINE BRAIN SHIFT ON MAGNETIC RESONANCE IMAGING AND SURVIVAL IN DOGS DIAGNOSED WITH MENINGOENCEPHALITIS OF UNKNOWN ETIOLOGY

Survival in dogs with meningoencephalomyelitis of unknown etiology with and without lesions detected by magnetic resonance imaging

BACKGROUND

The prognosis of individual dogs with meningoencephalomyelitis of unknown etiology (MUE) remains difficult to predict. MUE cases with no lesions detected by magnetic resonance imaging (MRI) occur, but it is unknown whether this finding is associated with prognosis.

HYPOTHESIS

MUE cases without detectable lesions on MRI have a better outcome than cases with detectable lesions.

ANIMALS

Study included 73 client-owned dogs with MUE presenting to Purdue University Veterinary Hospital from 2010 to 2020.

METHODS

Retrospective study. Dogs with a clinical diagnosis of MUE were identified by medical record search. MRI reports were reviewed for presence or absence of lesions consistent with MUE. Clinical findings at presentation, treatment, disease-specific survival, and outcomes including rates of remission and relapse were compared between cases with normal MRI or abnormal MRI.

RESULTS

Overall, 54 dogs (74%) were classified as abnormal MRI, and 19 dogs (26%) were classified as normal MRI cases. Death caused by MUE occurred in 1/19 (5%) normal MRI dogs and 18/54 (33%) abnormal MRI dogs (P = .016). Median survival was >107 months in both groups, but survival was significantly longer in the normal MRI group (P = .019). On multivariate analysis, abnormal MRI was significantly related to death (hazard ratio, 7.71; 95% confidence interval 1.03-58.00, P = .0470), whereas significant relationships with death were not identified for either the use of secondary immunosuppressive medications or cerebrospinal fluid nucleated cell count.

CONCLUSIONS

MUE dogs with no detectable lesions on MRI have reduced disease-related death compared with dogs with abnormal MRI. The presence or absence of MRI lesions in MUE dogs is prognostically relevant.

Clinical features, treatment, and outcome of juvenile dogs with meningoencephalitis of unknown etiology

BACKGROUND

The information relating to the outcome specifically for juvenile dogs with meningoencephalitis of unknown etiology (MUE) is lacking.

OBJECTIVES

To describe the clinical presentation, diagnostic findings, treatment, and outcome in a cohort of dogs with MUE <52 weeks old.

ANIMALS

Thirty-four client-owned dogs.

METHODS

Multicenter retrospective case series. Records from 5 referral centers were searched. Data was extracted from the medical records and referring veterinarians were contacted for survival data if this was not available from the record.

RESULTS

The mean age was 31 weeks; the youngest dog was 11 weeks and 3 dogs were <16 weeks old. Altered mentation (71%), ataxia (44%), seizures (29%), and circling (26%) were the most common presenting complaints. Neuroanatomical localization was to the forebrain (38%), multifocal (35%), brainstem (18%), and cerebellum (12%). Corticosteroid monotherapy (n = 15) and corticosteroid plus cytosine arabinoside (n = 15) were used in equal proportions. Outcome data was available for 26 dogs, 8 (31%) were alive at the time of data collection with a follow-up range of 135 to 2944 days. Death or euthanasia was related to MUE in 17/18 dogs that died during the study period. Kaplan-Meier survival analysis demonstrated a median survival time for all-cause death of 84 days.

CONCLUSION

The prognosis for MUE in this subset of dogs was considered poor.

Prognosis in meningoencephalitis of unknown origin in dogs: Risk factors associated with survival, clinical relapse, and long-term disability

BACKGROUND

Meningoencephalitis of unknown origin (MUO) comprises a group of noninfectious inflammatory diseases affecting the central nervous system of dogs. Previous studies have reported individual risk factors for survival but prognostication for MUO remains challenging.

OBJECTIVES

Identify clinical prognostic variables in dogs with MUO.

ANIMALS

A retrospective study of 447 dogs presented to 2 UK referral hospitals and diagnosed with MUO.

METHODS

Medical records of dogs diagnosed with MUO were retrospectively reviewed. Multivariable logistic regression was used for the identification of risk factors for survival and Cox proportional hazards analysis for the identification of risk factors for clinical relapse.

RESULTS

Eighty-two percent (366/447) of dogs with presumptive MUO survived to discharge and 63.5% (284/447) were alive at 6 months; 36% of the latter (103/284) had persistent neurological deficits. Breed (pugs; P = .03), epileptic seizures (P < .001), paresis (P < .001), and higher neurodisability scale (NDS) score (P < .001) at presentation were negatively associated with survival to 6 months. Dogs with persistent deficits had higher NDS scores on presentation (P = .001). Median follow-up time was 11 months (interquartile range [IQR], 1-24) and 50.6% (160/316) relapsed during treatment (median time to relapse, 7 months; IQR, 2-15). Incomplete resolution of the clinical signs during the 6 months after diagnosis (P < .001), higher NDS score (P < .001), and longer duration of the clinical signs (P < .001) were associated with relapse.

CONCLUSIONS AND CLINICAL IMPORTANCE

Knowledge of risk factors associated with survival, incomplete recovery and clinical relapse in MUO can help guide monitoring and treatment and improve owner communications regarding prognosis for this debilitating disease.

Corticosteroid monotherapy versus combined cytarabine continuous rate infusion and corticosteroid therapy in dogs with meningoencephalitis of unknown origin: A blinded, randomized, controlled trial

BACKGROUND

Treatment options available for meningoencephalitis of unknown origin (MUO) in dogs are suboptimal, and currently, no single treatment protocol appears to be superior.

OBJECTIVES

Compare neurological deterioration rates at 7 days between dogs with MUO treated with corticosteroids alone or combined with cytosine arabinoside (CA) continuous rate infusion (CRI) and compare clinical deterioration and survival at 30 and 100 days.

ANIMALS

Sixty-nine dogs with magnetic resonance imaging (MRI) and cerebrospinal fluid (CSF) features or both compatible with MUO.

METHODS

Parallel, blinded, randomized controlled trial. Simple randomization into 2 treatment groups: 4 mg/kg/day prednisolone (or dexamethasone equivalent) for 2 days or 200 mg/m2 CA CRI over 8 hours plus 2 mg/kg/day prednisolone. Blinding of the treatment protocol was carried out using reversible redaction of clinical records, and treatment failure was defined as deterioration of neurological assessment or death. Using intention-to-treat analysis, proportions failing treatment at 7, 30, and 100 days were compared using Fisher's exact test. All-cause mortality at 100 days was compared using Kaplan-Meier survival curves.

RESULTS

Thirty-five dogs were allocated to corticosteroid only, and 34 dogs were allocated to combined CA CRI and corticosteroid. Proportions failing treatment at 7, 30, and 100 days were 7/35 (20%), 9/35 (26%), and 15/35 (43%) in the corticosteroid-only group and 8/34 (24%), 11/34 (32%), and 23/34 (68%) in the corticosteroid and CA CRI group. All-cause mortality at 100 days was not significantly different between groups (P = .62). Clinically relevant treatment-related adverse effects were not observed.

CONCLUSIONS AND CLINICAL IMPORTANCE

We found no difference in outcome between corticosteroid monotherapy and combined cytarabine CRI and corticosteroid therapy at 7, 30, and 100 days after diagnosis in dogs with MUO.

Magnetic resonance imaging prognostic factors for survival and relapse in dogs with meningoencephalitis of unknown origin

Introduction

Canine meningoencephalitis of unknown origin (MUO) is a debilitating disease associated with high mortality. The prognostic value of magnetic resonance imaging (MRI) findings for predicting survival at 12 months and long-term relapse remains uncertain.

Methods

This was a retrospective cohort study evaluating the prognostic value of different MRI variables using multivariable logistic regression and Cox proportional hazards analysis.

Results

In total, 138 dogs were presumptively diagnosed with MUO. The most common location for lesions identified on MRI were the white matter tracts of the corona radiata and corpus callosum, followed by the frontal, sensorimotor and temporal cortices. Lower T2 lesion load (p = 0.006, OR = 0.942, CI = 0.902-0.983) was associated with longer survival and higher T1 post-contrast lesion load (p = 0.023, OR = 1.162, CI = 1.021-1.322) was associated with relapse.

Discussion

This study has identified prognostic factors that may help identify dogs at higher risk of death and relapse and therefore guide treatment recommendations.

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

BACKGROUND

Meningoencephalitis of unknown origin (MUO) comprises a group of debilitating inflammatory diseases affecting the central nervous system of dogs. Currently, no validated clinical scale is available for the objective assessment of MUO severity.

OBJECTIVES

Design a neurodisability scale (NDS) to grade clinical severity and determine its reliability and whether or not the score at presentation correlates with outcome.

ANIMALS

One hundred dogs with MUO were included for retrospective review and 31 dogs were subsequently enrolled for prospective evaluation.

METHODS

Medical records were retrospectively reviewed for 100 dogs diagnosed with MUO to identify the most frequent neurological examination findings. The NDS was designed based on these results and evaluated for prospective and retrospective use in a new population of MUO patients (n = 31) by different groups of independent blinded assessors, including calculation of interobserver agreement and association with outcome.

RESULTS

The most common clinical signs in MUO patients were used to inform categories for scoring in the NDS: seizure activity, ambulatory status, posture and cerebral, cerebellar, brainstem, and visual functions. The intraclass correlation coefficient (ICC) for prospective use of the NDS was 0.83 (95% confidence interval [CI], 0.68-0.91) indicating good agreement, and moderate agreement was found between prospective and retrospective assessors (ICC, 0.71; 95% CI, 0.56-0.83). No association was found between NDS score and long-term outcome.

CONCLUSIONS AND CLINICAL IMPORTANCE

The NDS is a novel clinical measure for objective assessment of neurological dysfunction and showed good reliability when used prospectively in MUO patients but, in this small population, no association with outcome could be identified.

Risk factors for early death or euthanasia within 100 days of diagnosis in dogs with meningoencephalitis of unknown origin

Meningoencephalitis of unknown origin (MUO) in the dog is an inflammatory condition of the central nervous system with variable short- and long-term prognosis. Previous studies have attempted to identify risk factors for early death; however, the findings were inconsistent and prognostication and treatment selection remain difficult for cases of MUO. The aim of this study was to compare the influence of putative prognostic factors on early survival in dogs with MUO. Logistic regression was used to analyse the effect of clinical and magnetic resonance imaging (MRI) features at diagnosis and type of immune-suppressive treatment received on survival at three-time points; 7 days, 30 days, and 100 days post-diagnosis. Ninety eight dogs were included. Dogs that were obtunded at presentation had a 6.6 times increased odds of death in the first 7 days after diagnosis, a 2.1 times increased risk of death 8-30 days after diagnosis, and a 1.9 times increased risk of death 31-100 days after diagnosis. No other clinical, MRI feature, or treatment was found to have a significant influence on survival. Obtundation at presentation was found to increase risk of early euthanasia in dogs with MUO, while the addition of an IV infusion of cytarabine to immune-suppressive corticosteroid therapy (prednisolone and/or dexamethasone) at initial treatment did not improve the odds of survival at 7, 30, or 100 days after diagnosis.

Clinical Presentation, Diagnostic Findings, and Long-term Survival Time in 182 Dogs With Meningoencephalitis of Unknown Origin From Central Europe That Were Administered Glucocorticosteroid Monotherapy

Canine non-infectious inflammatory meningoencephalomyelitis is termed meningoencephalomyelitis of unknown origin (MUO) and may affect dogs of every breed at any age. Treatment with immunosuppressive medication, the survival time based on MRI, and cerebrospinal fluid (CSF) findings has been widely reported; however, these studies only included a small number of patients, or they are summaries from the literature. Therefore, the aim of this study was to compare the clinical presentation, diagnostic findings, treatment protocol and long-term survival time in many dogs diagnosed with MUO in one clinic with previously published studies. One hundred eighty-two dogs met the inclusion criteria. Age, sex, duration of clinical signs before diagnosis, presence of neurological signs, MRI and CSF analysis were similar to those in previous reports. Our study revealed that dogs with a brainstem lesion have a 60% lower chance of death before 1 year than dogs with multifocal brain lesions. A total of 55.56% of treated dogs survived for more than 1 year, and 10.55% survived for more than 5 years since diagnosis. The median survival time for all dogs was 540 days. Our findings support glucocorticosteroid monotherapy as a viable treatment option for dogs with MUO.

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

Optic neuritis (ON) is a recognized condition, yet factors influencing recovery of vision are currently unknown. The purpose of this study was to identify prognostic factors for recovery of vision in canine ON of unknown etiology. Clinical databases of three referral hospitals were searched for dogs with presumptive ON based on clinicopathologic, MRI/CT, and fundoscopic findings. Twenty-six dogs diagnosed with presumptive ON of unknown etiology, isolated (I-ON) and MUE-associated (MUE-ON), were included in the study. Their medical records were reviewed retrospectively, and the association of complete recovery of vision with signalment, clinicopathologic findings, and treatment was investigated. Datasets were tested for normality using the D'Agostino and Shapiro-Wilk tests. Individual datasets were compared using the Chi-squared test, Fisher's exact test, and the Mann-Whitney U-test. For multiple comparisons with parametric datasets, the one-way analysis of variance (ANOVA) was performed, and for non-parametric datasets, the Kruskal-Wallis test was performed to test for independence. For all data, averages are expressed as median with interquartile range and significance set at p < 0.05. Twenty-six dogs met the inclusion criteria. Median follow-up was 230 days (range 21–1901 days, mean 496 days). Six dogs (23%) achieved complete recovery and 20 dogs (77%) incomplete or no recovery of vision. The presence of a reactive pupillary light reflex (p = 0.013), the absence of fundoscopic lesions (p = 0.0006), a younger age (p = 0.038), and a lower cerebrospinal fluid (CSF) total nucleated cell count (TNCC) (p = 0.022) were statistically associated with complete recovery of vision. Dogs with I-ON were significantly younger (p = 0.046) and had lower CSF TNCC (p = 0.030) compared to the MUE-ON group. This study identified prognostic factors that may influence complete recovery of vision in dogs with ON. A larger cohort of dogs is required to determine whether these findings are robust and whether additional parameters aid accurate prognosis for recovery of vision in canine ON.

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

Immune-mediated inflammation is responsible for about 25% of central nervous system disease in dogs. The disease can affect all ages and breeds, but young to middle-aged small breed dogs are over-represented for most forms. Diagnosis consists of advanced imaging (MRI), cerebrospinal fluid analysis, and infectious disease testing, but biopsy is required for definitive diagnosis and classification of the disease into one of the many subtypes. Treatment consists of immunosuppressive medication with the goal being to control and/or improve clinical signs. Current literature shows that prognosis is variable.

Clinical presentation, diagnostic findings, prognostic factors, treatment and outcome in dogs with meningoencephalomyelitis of unknown origin: A review

Meningoencephalomyelitis of unknown origin (MUO) encompasses a group of idiopathic, most likely immune mediated, inflammatory central nervous system diseases that cause clinical, diagnostic and treatment challenges to veterinary neurologists. Clinical criteria for obtaining this presumptive diagnosis are currently available, and multiple treatment protocols have previously been investigated in small (prospective or retrospective) case series. As this group of diseases is considered fatal if left untreated, the identification of clinically usable prognostic indices could be of great value. This review provides an overview of recent developments in the clinical presentation, diagnostic findings, possible prognostic factors, treatment and outcome in dogs diagnosed with MUO.