MELAS (Mitochondrial Myopathy and Encephalopathy, Lactic Acidosis, and Stroke Episodes)

  • An-Guor Wang


A 43-year-old female presented with complaints of sudden-onset blurred vision in both eyes this afternoon. She reported a past medical history of bilateral hearing impairment, type 1 diabetes mellitus, and hypertension. Her family history was positive for type 1 diabetes mellitus. Since yesterday, the patient had been experiencing nausea and diarrhea. Her headaches began in the morning, and by the afternoon, she reported blurred vision. At the emergency room, her vision was finger counting at 20 cm in the right eye and hand motion at 50 cm in the left eye. Intraocular pressures were normal. Her eyeballs showed nystagmoid movement with a fast phase to the left. There was full range of eye motion. Slit lamp examination showed normal anterior segments. Pupil response was also normal. Ophthalmoscopic examination revealed bilateral temporal optic disc pallor (Fig. 21.1). A confrontation test showed homonymous left field defects in both eyes. A CT scan of the brain showed symmetric calcification over the bilateral caudate, putamen, and pallidum (Fig. 21.2). Elevated blood lactate (22.2 mg/dL) was noted, and supportive treatment was given during the acute period. A brain MRI also revealed similar lesions in the basal ganglion which were hyperintense on a T1-weighted image and hypointense on FLAIR and T2-weighted images (Fig. 21.3). In addition, there was a diffuse, hyperintense lesion over the right temporo-occipital area on T2-weighted, FLAIR, and diffusion scans. However, the lesion did not show low values on ADC on the second day after onset (Fig. 21.4) and became depressed on the fourth day (Fig. 21.5). A visual field examination on the fourth day showed near total obscuration in both eyes (Fig. 21.6). Muscle biopsy showed nonspecific type 2 muscle atrophy. Peripheral blood DNA analysis revealed a mtDNA 3243 A>G mutation. The patient was diagnosed with mitochondrial myopathy and encephalopathy, lactic acidosis, and stroke episodes (MELAS). On the eighth day, her vision recovered to 6/8.6 in the right eye and 6/10 in the left eye. Four months later, her visual field recovered almost completely (Fig. 21.7).


  1. 1.
    Thambisetty M, Newman NJ. Diagnosis and management of MELAS. Expert Rev Mol Diagn. 2004;4(5):631–44.CrossRefPubMedGoogle Scholar
  2. 2.
    Sproule DM, Kaufmann P. Mitochondrial encephalopathy, lactic acidosis, and strokelike episodes: basic concepts, clinical phenotype, and therapeutic management of MELAS syndrome. Ann N Y Acad Sci. 2008;1142:133–58.CrossRefPubMedGoogle Scholar
  3. 3.
    Iizuka T, Sakai F. Pathophysiology of stroke-like episodes in MELAS: neuron-astrocyte uncoupling in neuronal hyperexcitability. Future Neurol. 2010;5:61–83.CrossRefGoogle Scholar
  4. 4.
    Goto YI, Horai S, Matsuoka T, et al. Mitochondrial myopathy, encephalopathy, lactic acidosis, and strokelike episodes (MELAS): a correlative study of the clinical features and mitochondrial DNA mutation. Neurology. 1992;42:545–50.CrossRefPubMedGoogle Scholar
  5. 5.
    Koga Y, Povalko N, Nishioka J, Katayama K, Kakimoto N, Matsuishi T. MELAS and L-arginine therapy: pathophysiology of stroke-like episodes. Ann N Y Acad Sci. 2010;1201:104–10.CrossRefPubMedGoogle Scholar
  6. 6.
    DiMauro S, Hirano M. MELAS. In: Pagon RA, Adam MP, Ardinger HH, Wallace SE, Amemiya A, Bean LJH, Bird TD, Ledbetter N, Mefford HC, Smith RJH, Stephens K, editors. GeneReviews® [Internet]. Seattle: University of Washington, Seattle; 1993–2017.Google Scholar
  7. 7.
    Hirano M, Pavlakis SG. Mitochondrial myopathy, encephalopathy, lactic acidosis, and strokelike episodes (MELAS): current concepts. J Child Neurol. 1994;9:4–13.CrossRefPubMedGoogle Scholar
  8. 8.
    Pauli W, Zarzycki A, Krzyształowski A, Walecka A. CT and MRI imaging of the brain in MELAS syndrome. Pol J Radiol. 2013;78(3):61–5.CrossRefPubMedPubMedCentralGoogle Scholar
  9. 9.
    Lin CM, Thajeb P. Valproic acid aggravates epilepsy due to MELAS in a patient with an A3243G mutation of mitochondrial DNA. Metab Brain Dis. 2007;22(1):105–9.CrossRefPubMedGoogle Scholar
  10. 10.
    Chiyonobu T, Noda R, Yoshida M, et al. Intestinal pseudo-obstruction in a patient with mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes (MELAS) associated with phenytoin therapy. Brain Dev. 2008;30(6):430–3.CrossRefPubMedGoogle Scholar

Copyright information

© Springer Nature Singapore Pte Ltd. 2018

Authors and Affiliations

  • An-Guor Wang
    • 1
  1. 1.Department of OphthalmologyTaipei Veterans General Hospital, National Yang-Ming University School of Medicine, Yun-San Ophthalmology Education Research FoundationTaipeiTaiwan

Personalised recommendations