Incidence, risk factors, and outcomes for early postoperative seizures in dogs with rostrotentorial brain tumors after intracranial surgery

Abstract

Background Seizures in the early postoperative period after intracranial surgery may affect outcome in dogs. Objectives To determine the incidence of early postoperative seizures (EPS) in dogs with brain tumors, identify specific risk factors for EPS, and determine if EPS affects outcome. Animals Eighty‐eight dogs that underwent 125 intracranial surgeries for diagnosis and treatment of rostrotentorial brain tumors. Methods Retrospective cohort study. All patients with a diagnosis of rostrotentorial brain tumor from 2006 to 2020 were included. Early postoperative seizures were diagnosed by observation of seizure activity within 14 days of neurosurgery. Previously diagnosed structural epilepsy, perioperative anticonvulsant drug (ACD) use, magnetic resonance imaging (MRI), and tumor characteristics were evaluated. Outcome measures included neurologic and nonneurologic complications, duration of hospitalization, and survival to discharge. Results Dogs with rostrotentorial brain tumors had EPS after 16/125 (12.8%) neurosurgical procedures (95% confidence interval [CI], 7%‐19%). Presence of previous structural epilepsy was not associated with EPS risk (P = 1). Perioperative ACD use also was not associated with EPS (P = .06). Dogs with EPS had longer hospitalization (P < .001), were more likely to have neurologic complications postsurgery (P = .01), and were less likely to survive to discharge (P = .01). Conclusions and Clinical Importance It is difficult to predict which dogs are at risk of EPS because the presence of previous structural epilepsy and the use of perioperative ACDs was not associated with EPS. However, seizures in the early postoperative period are clinically important because affected dogs had prolonged hospitalization, more neurologic complications, and decreased short‐term survival.

Clinical and Magnetic Resonance Imaging (MRI) Features, Tumour Localisation, and Survival of Dogs with Presumptive Brain Gliomas

“…Little information is available in the veterinary bibliography regarding the type of ES (focal, generalised, or focal with secondary generalisation) in dogs with brain tumours. Our results are consistent with most previous studies which describe generalised ES as being more common than focal [7,29,30]. However, the retrospective nature of studies may underestimate focal seizure onset, as focal origin may often be clinically inapparent, and prospective studies including more detailed anamnesis are lacking.…”

“…In one study, 43% of dogs with brain gliomas had CS [7]. However, in a recent study including different types of rostrotentorial brain tumours, only 9% of dogs developed CS and 8% SE [30]. In our study, 34 dogs (74% of dogs with ES) suffered from CS/SE.…”

“…In the other 48% of cases, the neurological exam was normal, or deficits were considered post-ictal. Other studies reported a variable absence of neurological deficits between 5% and 60% [5,6,30]. Interestingly, a considerable proportion of dogs had deficits on neurological examination while no other neurological signs had been observed by owners.…”

“…The most common clinical sign associated with brain tumours in dogs are ES [3,[28][29][30]. Reported structural epilepsy ranges from 50% to 75% in studies where all types of brain tumours are included [3,14,29,30].…”

“…The most common clinical sign associated with brain tumours in dogs are ES [3,[28][29][30]. Reported structural epilepsy ranges from 50% to 75% in studies where all types of brain tumours are included [3,14,29,30]. References including only suspected or confirmed brain gliomas report the occurrence of ES in 62% to 92% of dogs [5,7,12,13].…”