Types of Epilepsy

Types of Epilepsy

Epilepsy (from Ancient Greek ἐπιληψία) is a common and diverse set of chronic neurological disorders characterized by seizures. Some definitions of epilepsy require that seizures be recurrent and unprovoked, but others require only a single seizure combined with brain alterations which increase the chance of future seizures. Mutations in several genes have been linked to several types of epilepsy. Some genes that code for protein sub units of voltage-gated and ligand-gated ion channels have been associated with forms of generalized epilepsy and infantile seizure syndromes. One speculated mechanism for some forms of inherited epilepsy are mutations of the genes that code for sodium channel proteins; these defective sodium channels stay open for too long, thus making the neuron hyper-excitable. Glutamate, an excitatory neurotransmitter, may, therefore, be released from these neurons in large amounts, which — by binding with nearby glutamatergic neurons — triggers excessive calcium (Ca2+) release in these post-synaptic cells. Such excessive calcium release can be neurotoxic to the affected cell. The hippocampus, which contains a large volume of just such glutamatergic neurons (and NMDA receptors, which are permeable to Ca2+ entry after binding of both glutamate and glycine), is especially vulnerable to epileptic seizure, subsequent spread of excitation, and possible neuronal death. Another possible mechanism involves mutations leading to ineffective GABA (the brain's most common inhibitory neurotransmitter) action. Epilepsy-related mutations in some non-ion channel genes have also been identified.

Types of Epilepsy

Types of Epilepsy

Types of Epilepsy

Types of Epilepsy

Types of Epilepsy

Types of Epilepsy

Types of Epilepsy

Types of Epilepsy

Types of Epilepsy