A recent study published in the Journal of Neurology used electroencephalogram (EEG) and magnetic resonance imaging (MRI) scans to identify signs of status epilepticus in adults with mitochondrial diseases similar to thymidine kinase 2 deficiency (TK2d).
Epilepsy is fairly common among individuals with mitochondrial diseases, occurring in up to one-half of patients. Status epilepticus, which refers to one prolonged seizure or several seizures occurring close together, is a severe complication requiring immediate medical attention.
The study included 13 individuals with mitochondrial diseases who experienced at least one episode of status epilepticus. All participants received care at Pitié-Salpêtriere Hospital in Paris, France, between 2010 and 2021.
Focal seizures were the most commonly observed type of seizure, consistent with prior research. Only individuals with the mitochondrial disease myoclonus epilepsy with ragged-red fibers (MERRF) did not report focal seizures.
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Status epilepticus was not the first sign of mitochondrial disease for any of these individuals. Early signs included loss of coordination, deafness, retinopathy and muscle weakness.
Most individuals experienced one status epilepticus episode, though it varied in length from three up to 120 days. Some initial symptoms included confusion or altered consciousness, which were often followed by motor and visual signs. In four participants, potential triggers such as drug changes, stress and cardiac complications occurred prior to the beginning of a status epilepticus episode.
Of note, 12 participants reported stroke-like symptoms that began before the onset of status epilepticus. This was consistent with MRI findings, which revealed stroke-like lesions. The authors found that the development of these lesions coincided with the timing of status epilepticus in several individuals.
Furthermore, EEG testing revealed three distinct patterns of status epilepticus that differed in timing relative to the onset and duration of an episode.
“Future prospective studies incorporating standardized, serial EEG and MRI scans would be essential to better define the temporal dynamics of [status epilepticus] in [mitochondrial disease] and to refine our understanding of the electrophysiological correlates of seizures and metabolic dysfunction,” the authors concluded.
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