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- Lennox-Gastaut syndrome (LGS) is a challenging diagnosis in epileptology as could be misunderstood with different etiologies as focal cortical dysplasia (FCD) (Bourgeois et al., 2014).<\/li>\n
- If patient has many seizure types is more probably to be wrong diagnosed (Camfield & Camfield, 2007).<\/li>\n
- Moreover, mesial surface lesions (MSL) could result in false localizations leading to EEG misinterpretation.<\/li>\n
- In turn, patients with mesial lesions could have secondary bilateral synchrony (SBS) in EEG as showed by T\u00fckel and Jasper since the fifties (T\u00fckel & Jasper, 1952). It is described as 2-4Hz high-amplitude, synchronous, almost symmetric diffuse slow sharp waves<\/i> (DSSW).<\/li>\n<\/ul>\n
Objectives<\/strong><\/p>\n
To highlight SBS as an EEG\u2019s pitfall describing a case of FCD mimicking LGS.<\/p>\n
Case Report<\/strong><\/p>\n
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- A 9yo boy from Acre with previous LGS diagnosis performed pre-surgical evaluation for callosotomy in our epilepsy center.<\/li>\n
- His mother had malaria during pregnancy needing medications nonetheless without complications (term delivery).<\/li>\n
- His neurodevelopment was normal until 3yo when left focal motor seizures started and quickly evolved to tonic-clonic, tonic and drop seizures plus atypical absences.<\/li>\n
- Consequently, moderate neuro-psychomotor impairment occurred as mild left hemiparesis.<\/li>\n
- Serial EEGs showed LGS\u2019s hallmarks: 2.5Hz DSSW and generalized fast rhythm.<\/li>\n
- However, awake background activity was normal, an unexpected finding<\/i> in LGS due to be slow and poorly organized since its onset.<\/li>\n<\/ul>\n
Figure 1: <\/b>EEG records findings \u2013 pro and against LGS diagnosis.\u00a0<\/span><\/p>\n
![\"\"](\"https:\/\/elastic-goodall.132-148-76-14.plesk.page\/latam\/wp-content\/uploads\/2017\/03\/Imagem1_eng-300x197.png\")
<\/a>legend: (A, B) <\/b>In LGS\u2019s EEG pattern is expected a triad with 2.5Hz DSSW, generalized fast rhythm and poorly organized background. (C) <\/b>However, in this reported case a curious finding was his normal background when awake not fitting with LGS diagnosis.<\/span><\/p>\n- \n
- Video-EEG revealed stereotyped and predominantly focal seizures<\/i> beginning at right <\/i>fronto<\/i>-central <\/i>(RFC) regions that quickly diffuse bilaterally<\/i> as DSSW. In addition, all mentioned seizures were clinically recorded.<\/li>\n<\/ul>\n
Figure 2: <\/b>One electrographic seizure recorded during video-EEG with a focal beginning.<\/span><\/p>\n
- Video-EEG revealed stereotyped and predominantly focal seizures<\/i> beginning at right <\/i>fronto<\/i>-central <\/i>(RFC) regions that quickly diffuse bilaterally<\/i> as DSSW. In addition, all mentioned seizures were clinically recorded.<\/li>\n<\/ul>\n
![\"\"](\"https:\/\/elastic-goodall.132-148-76-14.plesk.page\/latam\/wp-content\/uploads\/2017\/03\/Imagem1_eng.png\")
<\/a>legend: (A, B) <\/b>In LGS\u2019s EEG pattern is expected a triad with 2.5Hz DSSW, generalized fast rhythm and poorly organized background. (C) <\/b>However, in this reported case a curious finding was his normal background when awake not fitting with LGS diagnosis.<\/span><\/p>\n