TY - JOUR
T1 - Neuronal hyperexcitability in stroke-like episodes of MELAS syndrome
AU - Iizuka, T.
AU - Sakai, F.
AU - Suzuki, N.
AU - Hata, T.
AU - Tsukahara, S.
AU - Fukuda, M.
AU - Takiyama, Y.
PY - 2002/9/24
Y1 - 2002/9/24
N2 - Background: The pathogenesis of stroke-like episodes in patients with mitochondrial myopathy, encephalopathy, lactic acidosis and stroke-like episodes (MELAS) remains unknown. Methods: Fourteen stroke-like episodes in six patients with MELAS were studied using clinical, neuroradiologic, and electrophysiologic approaches. In two patients postmortem examination was done. Results: Headache and epileptic seizure were the most common presenting symptoms. In 13 of 14 episodes the cerebral cortex was primarily involved with variable subcortical edema particularly in the temporal, occipital, and parietal cortex. Repeated MRI performed in two episodes revealed progressive spread of the cortical lesion to the surrounding cortex for a few weeks after the onset of symptoms. In 6 of 11 episodes T1-weighted hyperintense cortical signal compatible with cortical laminar necrosis was seen during subacute stage of the episode. Fat-suppression MRI confirmed intracortical gyral hemorrhage in one episode. Petechial gyral microhemorrhages were also pathologically confirmed in the autopsy of another patient. In 9 of 11 episodes focal epileptiform discharges on EEG were noted in the acute brain lesion. In seven of nine episodes focal cortical hyperperfusion was seen in SPECT studies. Conclusion: The stroke-ike episodes in MELAS may reflect neuronal hyperexcitability, which increases energy demand and creates energy imbalance between energy requirement and adequate availability of adenosine triphosphate due to oxidative phosphorylation defect particularly in the susceptible neuronal population, causing cortical necrosis. The episodic nature of stroke-like episodes is unexplained.
AB - Background: The pathogenesis of stroke-like episodes in patients with mitochondrial myopathy, encephalopathy, lactic acidosis and stroke-like episodes (MELAS) remains unknown. Methods: Fourteen stroke-like episodes in six patients with MELAS were studied using clinical, neuroradiologic, and electrophysiologic approaches. In two patients postmortem examination was done. Results: Headache and epileptic seizure were the most common presenting symptoms. In 13 of 14 episodes the cerebral cortex was primarily involved with variable subcortical edema particularly in the temporal, occipital, and parietal cortex. Repeated MRI performed in two episodes revealed progressive spread of the cortical lesion to the surrounding cortex for a few weeks after the onset of symptoms. In 6 of 11 episodes T1-weighted hyperintense cortical signal compatible with cortical laminar necrosis was seen during subacute stage of the episode. Fat-suppression MRI confirmed intracortical gyral hemorrhage in one episode. Petechial gyral microhemorrhages were also pathologically confirmed in the autopsy of another patient. In 9 of 11 episodes focal epileptiform discharges on EEG were noted in the acute brain lesion. In seven of nine episodes focal cortical hyperperfusion was seen in SPECT studies. Conclusion: The stroke-ike episodes in MELAS may reflect neuronal hyperexcitability, which increases energy demand and creates energy imbalance between energy requirement and adequate availability of adenosine triphosphate due to oxidative phosphorylation defect particularly in the susceptible neuronal population, causing cortical necrosis. The episodic nature of stroke-like episodes is unexplained.
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U2 - 10.1212/WNL.59.6.816
DO - 10.1212/WNL.59.6.816
M3 - Article
C2 - 12297560
AN - SCOPUS:0037167550
VL - 59
SP - 816
EP - 824
JO - Neurology
JF - Neurology
SN - 0028-3878
IS - 6
ER -