The primary objectives of this study were to classify and quantify epileptic seizures as a symptom of onset or later in the course of the disease and the correlation between International League Against Epilepsy (ILAE) 1981 and 2017 classifications. The secondary objectives were to quantify: 1) the cases in which epileptic seizures were reclassified; 2) patients who received antiepileptic drugs (AEDs) as monotherapy; 3) patients whose antiepileptic treatment on admission was modified; and (4) patients whose seizures were controlled with the prescribed AEDs.

Epilepsy is a common symptom in patients with primary CNS tumors. The recognition and classification of epileptic seizures and providing effective treatment are essential to preserve the quality of life of patients with glial tumors.

This is a prospective, descriptive, observational, clinical study of 168 patients diagnosed with primary CNS tumor during the period January 2010-March 2013. We used WHO CNS classification of tumors and the ILAE 1981 classification and its correlation with that of 2017.

Eighty-two cases with glial tumors were analyzed; 5 infratentorial cases were excluded. Seventy four percent (57/77) had secondary epilepsy with 79% as an initial symptom and 21% during the disease course. Seizure types included: 39% focal aware, 13% focal impaired awareness, 11% focal to bilateral tonic-clonic and 37% generalized onset motor tonic-clonic. After seizure reclassification, generalized onset motor seizures decreased from 37% to 17% and focal to bilateral tonic-clonic seizures increased to 31%. Prophylaxis therapy was discontinued in 20/75 patients (27%). The ILAE 2017 Classification of Seizure Types was convenient and practical. Among patients receiving levetiracetam monotherapy, 95% were seizure-free. 

The transition of the ILAE classification from 1981 to 2017 was favorable, coherent, and with phenomenological improvement. Focal seizures are the most common type in patients with glial tumors, and levetiracetam used as monotherapy is suitable for these patients.