Pathophysiology and antiepileptic drug therapy in tumor-associated epilepsy and its implications in status epilepticus

Introduction: Seizures occur in 20–45% of patients with brain tumors. They are also at risk of developing status epilepticus (SE). This reinforces the importance of adequate therapeutic management of tumor-associated epilepsy (TAE). Method: A retrospective chart review was done, of twenty patients who presented with TAE from 2006 to 2009. The type and location of the tumor, type of seizure experienced, choice of antiepileptic drugs (AEDs) were noted. A literature review was undertaken. MEDLINE was searched for systematic reviews from 1950 to 2010, twenty-eight journal articles were selected. Comparisons were made between the retrospective chart review and the literature review. Treatment complications and implications in SE were investigated. Results: Multifactorial pathophysiological mechanisms involving a complex interplay between histological, anatomical, biochemical, physiological and genetic factors have been suggested. Contrary to literature, complex partial seizures (30%) were more common compared to simple partial seizures (10%). Similar to literature, lesions in the frontal (35%) and temporal (50%) lobes had the highest epileptogenecity compared to the occipital (5%) lobe. SE occurred in 15% of the patients. Even though valproate and levetiracetam was the best combination of AEDs suggested, it was only used in 10% of patients. Instead valproate and phenytoin were used (20%). Phenytoin was preferred in SE (66%) and in monotherapy (25%) instead of Levetiracetam. However treatment complications exist. Conclusion: The best choice of AEDs remains controversial due to the underlying pathophysiological complexity. Type of seizure, treatment complications and individual patient factors therefore need to be considered. Development of novel therapies targeting multiple pathophysiological mechanisms coupled with intrinsic antineoplastic activity would be desirable