Usefulness of neurological assessment scales in prognosis of meningoencephalitis of unknown origin in Yorkshire Terriers

Abstract

Background – Attempts to determine the prognostic factors that affect the survival time of canine patients with meningoencephalitis of unknown origin (MUO) have provided highly variable results. Scaled complex ratings to predict general outcomes are required. This study aimed to determine whether neurological assessment scales could be useful in the prognosis of Yorkshire Terriers with MUO. The study population comprised 127 Yorkshire terriers who met the inclusion criteria for a highly probable diagnosis of MUO. This multicenter, cohort study was designed as a retrospective review of medical records. Based on documented neurological examinations, animals were scored on three scales: the Modified Glasgow Coma Scale, Neuro Disability Scale 1 (Smith et al.), and Neuro Disability Scale 2 (Gonçalves et al.). The association between the scores and survival time was investigated over three time periods. Results – All scales were significantly associated (p<0.001) with MUO-specific survival and death owing to MUO within the first 7 days and had high prognostic accuracy in terms of short-term prognosis. None of the scales was significantly associated with the probability of survival after 100 or 365 days. Dogs with unilateral lesions on magnetic resonance images (MRI) had approximately 12- and 3-fold higher odds of surviving until 100 and 365 days, respectively, than dogs with bilateral lesions on MRI. Dogs heavier than 3.2 kg at presentation had approximately 6-fold higher odds of survival until day 365. Conclusions - The study provides strong evidence for a high short-term prognostic accuracy of the three neurological assessment scales in Yorkshire Terriers with MUO – the scales seem to be very useful in predicting death within the first week of the onset of MUO. Prognostic potential of the scales disappears, however, in the longer perspective and their place is taken by the spread of pathological lesions visualized in MRI and a patient’s weight.