Epilepsy Associated With Mitochondrial Encephalomyopathy, Lactic Acidosis, and Stroke-Like Episodes

Abstract

Objectives: The present study explored the clinical characteristics and prognostic factors of epilepsy in patients with mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes (MELAS).Methods: Thirty-four MELAS patients were included in the present study. They were diagnosed by clinical characteristics, genetic testing, muscle biopsy, and retrospective analysis of other clinical data. The patients were divided into three groups according to the effects of treatment after at least 2 years of follow-up.Results: Epilepsy was more common in male MELAS patients than in females (20/14). The age of onset ranged from 0.5 to 57 years, with an average of 22.6 years. Patients with epilepsy and MELAS had various forms of seizures. Focal seizures were the most common type affecting 58.82% of patients, and some patients had multiple types of seizures. The abnormal EEG waves were mainly concentrated in the occipital (69.57%), frontal (65.22%) and temporal lobes (47.83%). Overall, the prognosis of patients with epilepsy and MELAS was poor. Poor prognosis was associated with brain atrophy (P = 0.026), status epilepticus (P < 0.001), and use of anti-seizure medications with high mitochondrial toxicity (P = 0.015).Interpretation: Avoiding the application of anti-seizure medications with high mitochondrial toxicity, controlling seizures more actively and effectively, and delaying the occurrence and progression of brain atrophy as much as possible are particularly important to improve the prognosis of patients with MELAS and epilepsy.

Seizure Semiology, EEG, and Imaging Findings in Epilepsy Secondary to Mitochondrial Disease

“…In a series of 19 patients with POLG1, occipital rhythmic slowing was present in 7 patients and occipital interictal discharges was present in 18 patients, demonstrating an occipital predilection in POLG ( 15 ). This finding, as seen in our study over the disease course, is concordant with electrophysiologic data reported by other authors ( 10 , 16 , 28 , 29 ). Occipital status epilepticus and occipital seizures have also been previously reported in MELAS; this manifestation may precede other clinical signs of the disease and serve as a potential diagnostic clue ( 29 , 32 , 33 ).…”

“…Our findings are supported by previous patient series and literature reviews on epilepsy features in mitochondrial disorders (Table 3) (8,10,16,(28)(29)(30)(31). Focal seizures were the predominant seizure type in our series, which is in agreement with the previous review by Anagnostou et al in POLG and a recent case series in MELAS by Li et al (10,28).…”

“…Our findings are supported by previous patient series and literature reviews on epilepsy features in mitochondrial disorders ( Table 3 ) ( 8 , 10 , 16 , 28 – 31 ). Focal seizures were the predominant seizure type in our series, which is in agreement with the previous review by Anagnostou et al in POLG and a recent case series in MELAS by Li et al ( 10 , 28 ). In a series of 19 patients with POLG1, occipital rhythmic slowing was present in 7 patients and occipital interictal discharges was present in 18 patients, demonstrating an occipital predilection in POLG ( 15 ).…”

Ischemic and Metabolic Stroke Can Co-occur in m.3243A>G Carriers: A Case Report

“…Whether seizure activity triggered the development of the SLE, particularly the neuropsychological deficits at onset, remains speculative but is conceivable since SLEs are frequently accompanied by seizures [7]. Arguments against a seizure as the cause of the lesion are that relatives or caregivers did not observe a seizure shortly before or during admission, that the initial EEG did not show any epileptiform discharges, and that the lesion did not show an increase in volume, as is often found in seizure MRIs [8].…”

Mitochondrial Strokes: Diagnostic Challenges and Chameleons

“…Focal seizures are more common than generalised and EEG abnormalities tend to arise from the occipital, frontal, and temporal lobes. The mean age of onset is variable, with an average of 23 years [31]. The presence of epilepsy in MELAS is associated with a poor prognosis, particularly when they occur early in the disease course, if they are associated with status epilepticus, or if they are refractory to anticonvulsants [31,32].…”