EPILEPSY

Definition

Abnormal and recurrent excessive synchronized discharge of cerebral neuron with clinical manifestation of epileptic seizure which are an intermittent stereotypical behavior, emotion, motor function or sensation.

Pathophysiology

•       Paroxysmal depolarization shift (PDS) of the resting membrane potential, which triggers a brief rapid   burst of action potentials terminated by a sustained after hyperpolarization

•   PDS : result of imbalance between excitatory (glutamate and aspartate) and inhibitory (GABA) neurotransmitters

•         Abnormalities of voltage controlled membrane ion channels

•        Imbalance between endogenous neuromodulators, acetylcholine favoring depolarization and dopamine enhancing neuronal membrane stability

Focal Epiloptogenesis

•          Asynchronous burst firing in some hypocampal and cortical neurons

Generalized Epiloptogenesis

·         asynchronous burst firing in abnormal thalamocortical interaction

Etiology

•          Idiopathic

•          Cryptogenic

•          Symptomatic