Precipitation of stroke-like event by chickenpox in a child with MELAS syndrome.

The mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes syndrome (MELAS) is a rare congenital disorder of mitochondrial DNA (mtDNA). Herein we report a case of MELAS, whose second stroke-like episode was provoked by chickenpox. A point mutation at nucleotide (nt) 3243 in mtDNA supported the diagnosis of MELAS in this case. History of myopathy, the presence of lesions that did not conform to accepted distributions of vascular territories on cranial magnetic resonance imaging (MRI), normal result of cranial magnetic resonance angiography, hyperintensity on diffusion weighted MRI and apparent diffusion coefficient mapping indicating the presence of vasogenic edema in the fresh stroke-like lesion, and mitochondrial DNA analysis helped to exclude the diagnosis of ischemic cerebral infarction which can also be induced by chickenpox.