109 Hemimegalencephaly and Ohtahara syndrome causing neonatal seizure – a case report

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Hemimegalencephaly (HME) is rare congenital, hamartomatuous malformation of the brain cortical development characterised by enlargement of all or a part of one cerebral hemisphere. It is estimated that prevalence range is from 1 to 3 cases per 1000 children with epilepsy, and 1-14% among children with disturbed cortical development. Ohtahara syndrome is a rare infant epilepsy syndrome, characterised by ‘’burst supression’’ pattern in EEG (high amplitude spikes followed by little brain activity or flattening of the brain waves). It is accompanied by severe neurodevelopemental delay, presumably caused by HME as a structural malformation. We present a case of female premature newborn from bichorionic, biamniotic twin pregnancy, who was delivered vaginally after 35 weeks and 6 days, as the first twin. Apgar scores after 1 and 5 minutes were 10, physical examination was uneventful. The first in vitro fertilization resulted in twin pregnancy of 27-year healthy mother. Apart from oligohydramnios before delivery, pregnancy was uneventful. Family history of both parents was unremarkable. At the age of 24-hours baby girl developed first tonic spasms lasting one minute and spontaneously ceasing, without losing consciousness. She received intravenous Phenobarbital 10 mg/kg followed by 5 mg/kg/day. Initial laboratory findings including lumbal pucture and initial metabolic evaluation were all unremarkable. A tumor or congenital malformation of the left hemisphere of the brain was suspected after the first two dimensional brain ultrasonography. Multi Slice Computed Tomography (MSCT) revealed left HME, confirmed with the magnetic resonance imaging (MRI) together with polymicrogyria of frontal lobe, atypical form of the left Sylvian fissure and the left frontal ventriculomegaly. She developed refractory seizures (tonic; focal with automatisms – squelching, eye blinking; generalised, often waking her up from sleep). EEG showed suppression burst pattern and after extensive diagnostic evaluation the Ohtahara syndrome was diagnosed. Despite several different antiepileptic drugs, and their different combination, frequency and severity of the seizures did not improve and she developed severe developmental delay. At the age of 10 months she underwent functional hemispherotomy, and so far, eight months after the surgery she experienced no seizures together with major improvement in neuromotor development (despite strabismus and right hemiparesis which occurred after surgery). Her twin sister is healthy, normally developing, without seizures. Our findings are in comply with the data from the literature, claiming that after surgery the improvement of the patients is remarkable.

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