Caso electroencefalográfico: epilepsia mioclónica precoce

• Author(s): Monteiro, Tânia ; Martins, Esmeralda ; Chorão, Rui
• Date: 2011
• Persistent ID: http://hdl.handle.net/10400.16/1341
• Origin: Repositório Científico do Centro Hospitalar do Porto
• Subject(s): Supression-burst EEG pattern; early myoclonic epilepsy; nonketotic hyperglycinemia
• Document Type: Article
• Language: Portuguese

Description

ABSTRACT Introduction: The suppression-burst (SB) electroencephalographic pattern is rather common during the neonatal period and suggests severe encephalopathy. When significant hypoxic-ischemic insult is excluded, brain malformations and metabolic disorders have to be ruled out. Two distinctive epileptic syndromes are described: early epileptic encephalopathy with SB (Ohtahara syndrome) and early myoclonic epilepsy (EME). The later is frequently associated with neurometabolic disorders, one of the most common being nonketotic hyperglycinemia (NKH). Case report: A baby girl presented with multiple erratic clonic and myoclonic seizures from the second day of life, refractory to antiepileptic drugs. She was hypotonic, lethargic and had episodes of apnea. The electroencephalogram (EEG) showed multiple bursts of multifocal epileptiform activity with long periods of almost flat tracing; this pattern persisted beyond the neonatal period, it was present at the last EEG performed at age four months. Barbiturate-induced coma with mechanical ventilation was induced. She died at the age of five months. The second but not the first sample of cerebrospinal fluid (CSF) and blood revealed an increased CSF/serum glycine ratio (0,11 – normal<0,03). Post-morten liver tissue biopsy found a defi cit at the glycine cleavage system (GCS) (6,6 mkat/ kg - normal 45,0-195,0) and molecular studies detected a mutation in the gene GLDC molecular testing. This result allowed better parent’s genetic counseling. Conclusions: Early myoclonic epilepsy presents with multifocal seizures and SB on pattern on the EEG in the neonatal period, metabolic causes must be investigated, namely the neonatal form of NHK. CSF and plasma aminoacids, including glycine levels, should be measured, simultaneously and sometimes repeatedly. Enzymatic and molecular analysis may confirm this diagnosis and are useful for parent’s genetic counseling.