Canine intracranial neoplasia: clinical risk factors for development of epileptic seizures

Objectives: To identify clinical risk factors for seizures in dogs with intracranial neoplasia. METHOD: A cross-sectional retrospective study of 68 dogs with histopathologically confirmed primary or secondary intracranial neoplasia, complete clinical history and magnetic resonance imaging of the brain was conducted. Signalment and clinical history were retrieved from clinical records and magnetic resonance images of the brain were re-evaluated. Prevalence of findings was compared between dogs with and without seizures. RESULTS: Forty-two dogs had tumour-related seizures, the remaining 26 were seizure-free. Tumour types included meningioma (23 dogs with and 5 without seizures), glioma (9 dogs with and 6 without seizures), choroid plexus tumour (2 dogs without seizures), neuroblastoma (1 dog with seizures) and metastatic/invasive tumours including lymphoma (9 dogs with and 13 without seizures). On the basis of multi-variable logistic regression analysis, risk factors for seizures associated with intracranial neoplasia were magnetic resonance imaging findings consistent with the presence of neoplastic tissue in frontal lobe [odds ratio (OR) 9.61; 95% confidence interval (CI) 2.59 to 35.61], marked gadolinium enhancement (OR 10.41; 95% CI 2.07 to 52.30) and magnetic resonance imaging findings of subfalcine and/or subtentorial herniation (OR 3.88; 95% CI 1.10 to 13.71). CLINICAL SIGNIFICANCE: Dogs with primary or secondary intracranial neoplasia are at risk of seizures, particularly those with tumours that affect the frontal lobe, enhance markedly with gadolinium, or cause subfalcine and/or subtentorial herniation.