Description of neurological mimics presented to the neurology service of a small animal referral hospital.

BACKGROUND: Clinicians observe that cats and dogs referred to neurology services often do not have an underlying neurological disorder. There has been no analysis of the frequency or categorisation of these neurological mimics. METHODS: Retrospective study of 520 cases was carried out. Data on signalment, presenting clinical signs, neurological examination findings and final diagnosis were collected. Final diagnoses were classified as primary neurological, non-neurological in origin but with neurological clinical manifestation, completely non-neurological (neurological mimics) or undiagnosed. Presenting clinical signs and neurological examination results were compared between neurological mimics and primary neurological cases using Chi-square or Fischer exact test. Relative risk (RR) was calculated for significant associations. RESULTS: A total of 74% were primary neurological conditions, 8% neurological mimics, 3% non-neurological with neurological manifestation and 15% undiagnosed. An animal referred for lameness was approximately five times more likely to be diagnosed as a neurological mimic than as a primary neurological disorder (RR = 5.42, p < 0.001). Cases with a normal neurological examination were approximately 15 times more likely to be a neurological mimic (RR = 14.97, p < 0.001). CONCLUSION: Thorough examination with consideration of alternative diagnoses is important when a neurological condition is suspected in an animal that presents with lameness or normal neurological examination.

Effect of radiotherapy on freedom from seizures in dogs with brain tumors.

BACKGROUND: Seizures are a common presenting sign in dogs with brain tumors. HYPOTHESIS/OBJECTIVES: To investigate the effect of radiotherapy on freedom from brain tumor-associated seizures and survival time in dogs. ANIMALS: Thirty-two client-owned dogs with brain tumor-associated seizures; 18 received medical treatment and radiotherapy, 14 received medical treatment alone. METHODS: Multicenter retrospective study. Baseline characteristics (seizure semiology, magnetic resonance imaging [MRI] characteristics, and treatment) and duration of seizure freedom were recorded for the 2 treatment groups. Duration of seizure freedom between groups was compared (log-rank test) using Cox's proportional hazard analysis, with baseline characteristics entered as covariates. RESULTS: The duration of seizure freedom and survival time were significantly longer in the radiotherapy group (P < .001), with a mean of 24 months (95% confidence interval [CI], 14.3-33.8) versus 1.7 months in the control group (95% CI, 0.5-2.9) and a mean of 34.6 months (95% CI: 25.2-44.1) versus 6.2 months in the control group (95% CI, 2.6-9.7) respectively. Baseline characteristics were not associated with duration of seizure freedom after the start of treatment. In the radiotherapy group, 5 dogs were euthanized during the study period because of causes other than seizures. In the control group, recurrence of seizures was observed before death in all dogs. CONCLUSIONS AND CLINICAL IMPORTANCE: A longer period of seizure freedom and longer survival time was observed in dogs with brain tumors after radiotherapy compared to medical treatment only. The pathophysiological mechanisms of epileptogenesis and the effect of radiation therapy on seizure control are unclear to date. Further prospective studies are needed.