Epileptic encephalopathy

Abstract

Epileptic encephalopathies are conditions in which neurologic deterioration results mainly from epileptic activity. It can be due to very frequent or severe seizures, or to subcontinuous paroxysmal interictal activity. The former consists mainly of severe myoclonic epilepsy in infancy (SMEN), in which patients exhibit seizures from the middle of the first year of life with repeated episodes of status epilepticus, and migrating partial epilepsy in infancy, in which, from the first trimester of life, partial seizures affect various areas of the cortex randomly and in a subcontinuous fashion. Cases with subcontinuous paroxysmal interictal activity affect newborns with suppression bursts, thus consisting of either Ohtahara syndrome or neonatal myoclonic encephalopathy, and infants with infantile spasms (IS), although rare cases do not start until age 4 years. In childhood, it consists of various types of generalized seizures combined with either slow spike-waves of the Lennox-Gastaut syndrome (LGS) or with myoclonus and 3-Hz spike-waves of myoclonic-astatic epilepsy, and continuous spike-waves in slow sleep (CSWS) combined with various neuropsychological patterns including Landau-Kleffner syndrome, frontal lobe syndrome, orofacial dyspraxia, or negative myoclonus. Management differs for all these syndromes, with the combination of clobazam (CLB) and stiripentol (STP) being promising for SMEN, vigabatrin (VGB) for IS, lamotrigine (LTG) for LGS, and steroids for CSWS. It is important to avoid potential drug-induced worsening by phenobarbital (PB), phenytoin (PHT), carbamazepine (CBZ), tiagabine (TGB), and VGB; in children and especially in infants, treatment with valproate is preferred each time the proper diagnosis is not reached.