case_images: PMC11176442_01
case_images: Timeline of MELAS and therapeutic regimens.
case_images: fgene-15-1367716-g001.jpg
case_images: PMC11176442_01_fgene-15-1367716-g001.jpg
case_images: F1
case_images: A 66-year-old female patient was first admitted to another hospital 1 day after the onset of acute cognitive impairment and psychobehavioural abnormalities, accompanied by hallucinations and fever (Figure 1). One year later, she was admitted to our hospital due to paroxysmal unconsciousness with limb rigidity (Figure 1).
case_images: MR imaging findings. (A) Diffusion weighted imaging (DWI) (a-d) and fluid-attenuated inversion recovery (FLAIR) (e-h) images at first presentation. FLAIR imaging reveals high-intensity lesions in the bilateral frontal lobe and paraventricular area. The left temporal, parietal, occipital and bilateral frontal lobes are hyperintense on DWI. (B) Diffusion weighted imaging (DWI) (a-d) and fluid-attenuated inversion recovery (FLAIR) (e-h) images of the case at second presentation. FLAIR reveals high-intensity lesions in cortical and subcortical areas of the right frontal, temporal, parietal and occipital lobes. The bilateral frontal lobes and corpus callosum are hyperintense on DWI.
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case_images: PMC11176442_01_fgene-15-1367716-g002.jpg
case_images: F2
case_images: Brain magnetic resonance imaging (MRI) revealed high-intensity lesions in the left temporoparietal and occipital areas and bilateral frontal lobe area on diffusion weighted imaging (DWI) and fluid-attenuated inversion recovery (FLAIR) imaging (Figure 2A). The right frontal, temporal, parietal, and occipital cortices showed oedema with a slightly elevated FLAIR signal (Figure 2B).
case_images: MR spectroscopy findings. Magnetic resonance spectroscopy (MRS) reveals a decreased N-acetyl aspartate (NAA) level and increased Cho and Cr levels and lactic acid peak in right frontal, temporal, parietal and occipital lesions relative to the contralateral, normal areas.
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case_images: PMC11176442_01_fgene-15-1367716-g003.jpg
case_images: F3
case_images: MRI perfusion imaging was performed, and the results showed a decrease in time to peak (TTP) and mean transit time (MTT) and an increase in cerebral blood volume (CBV) and cerebral blood flow (CBF) in the right frontal, temporal, parietal, and occipital areas, which were considered hyperperfusion manifestations, while hypoperfusion manifestations in the left lateral ventricle were considered a compensatory phase. Magnetic resonance spectroscopy (MRS) revealed an elevated and inverted lactate peak with a decreased N-acetyl-aspartate level (Figure 3).
case_images: Pathological findings from biopsied muscle. No RRF was found on modified Gomori trichrome (MGT) staining (A); no obvious disordered arrangement of myofibrillar reticulum was observed on nicotinamide adenine dinucleotide (NADH) staining (B); no ragged-blue fibres or succinate dehydrogenase (SDH) strongly reactive blood vessels were observed on SDH staining (C); no COX-negative fibres were found (D); no significant increase in fat droplets was observed on Oil Red O (ORO) staining (E); no significant increase in glycogen was detected with Periodic acid-Schiff (PAS) staining (F).
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case_images: PMC11176442_01_fgene-15-1367716-g004.jpg
case_images: F4
case_images: However, the muscle biopsy results did not reveal ragged-red fibres (RRFs), which are the classic manifestation of MELAS (Figure 4).