Dados do Trabalho

Título

ICTAL BRADYCARDIA AS A CLUE TO SCN8A MUTATION DIAGNOSIS

Apresentação do Caso

A 2 month-year-old male started having recurrent epileptic seizures after a period of normal development. At 3 months he was admitted to our hospital with the diagnosis of status epilepticus. Laboratory exams, including cerebrospinal fluid, and neuroimaging were normal. He was then admitted to the Intensive Care Unit, where he received optimized treatment with antiseizure medications, including phenobarbital, phenytoin, levetiracetam, topiramate, as well as benzodiazepines. During the hospitalization, he developed daily seizures associated with dysautonomia, including significant bradycardia (27 to 60 bpm). Cardiac holter demonstrated sinus bradycardia exclusively associated to the epileptic events. The video-electroencephalogram confirmed ictal bradycardia. Considering the possibility of an epileptic encephalopathy associated with mutations of the sodium channel subunits, more specifically, a mutation in the SCN8A gene, carbamazepine was started. He evolved with outstanding seizure control. In the evolution, the child presented a single seizure in the 6-months follow-up. He also presented slowly improvement of the neurodevelopment and a frontotemporal atrophy in the control neuroimaging. At 10 months of life, he had orolingual dyskinesia, appendicular hypertonia and could sit on his own. The next-generation sequencing confirmed the SCN 8A mutation.

Discussão

Among the etiologies of the epileptic encephalopathies in infancy, the channelopathies play an important role. The sodium channel variants are the most frequent and some of those, such as SCN1A mutation, can be worsened by the administration of sodium channel blockers. On the other hand, the SCN8A mutation, a less known cause of epileptic encephalopathy, can respond dramatically with sodium channel blockers.

Comentários Finais

In this case, the diagnosis of this SCN8A channelopathy is especially important due to the treatment implications. However we can’t always count on fast genetic results, specially in public health

systems. The ictal bradycardia was the clue to this diagnosis. The possibility of SCN8A mutation should be considered in infants with focal seizures and bradycardia.

Referências (se houver)

Larsen, Jan & Carvill, Gemma & Gardella, Elena & Kluger, Gerhard & Schmiedel, Gudrun & Barisic, Nina & Depienne, Christel & Brilstra, E.H. & Mang, Yuan & Nielsen, Jens & Kirkpatrick, Martin & Goudie, David & Goldman, Rebecca & Jähn, Johanna & Jepsen, Birgit & Gill, Deepak & Döcker, Miriam & Biskup, Saskia & McMahon, Jacinta & Møller, Rikke. (2015). The phenotypic spectrum of SCN8A encephalopathy. Neurology. 84. 10.1212/WNL.0000000000001211.

Trivisano, Marina & Pavia, Giusy & Ferretti, Alessandro & Fusco, Lucia & Vigevano, Federico & Specchio, Nicola. (2019). Generalized tonic seizures with autonomic signs are the hallmark of SCN8A developmental and epileptic encephalopathy. Epilepsy & Behavior. 96. 219-223. 10.1016/j.yebeh.2019.03.043.

Declaração de conflito de interesses de TODOS os autores

Não há conflito de interesses de nenhum dos autores