Neurology: Case of the Month

Test Yourself — Patient 87

Symptomatic Localization-Related Epilepsy associated with a mitochondrial disorder, MELAS (mitochondrial myopathy, encephalopathy, lactic acidosis and stroke-like episodes)

  1. Is the most common mutation in MELAS the A3243G tRNA mitochondrial gene mutation?
    • [ A ] True.
    • [ B ] False.
  2. Which of the following is INCORRECT regarding mitochondrial disease?
    • [ A ] Maternal inheritance.
    • [ B ] It is a disease of mitochondrial gene mutations.
    • [ C ] There are multiple phenotypes that may be seen with the same mitochondrial gene mutation.
    • [ D ] Pathophysiology of mitochondrial disorders can be secondary to heteroplasmy.
    • [ E ] Paternal inheritance.
  3. What is the typical presentation for MELAS?
    • [ A ] Myoclonic epilepsy with ragged red fibers.
    • [ B ] Progressive optic neuropathy with loss of central vision and scotoma.
    • [ C ] Myopathy, encephalopathy, lactic acidosis and stroke-like episodes.
    • [ D ] Peripheral neuropathy, ataxia and retinitis pigmentosa.
    • [ E ] Progressive external opthalmoplegia, cardiomyopathy, conduction block, short stature.
  4. Which of the following is an INCORRECT sign or finding indicative of MELAS?
    • [ A ] Typically present at greater than 50 years of age.
    • [ B ] Encephalopathy with seizures.
    • [ C ] High serum or CSF lactate.
    • [ D ] Ragged-red fibers.
    • [ E ] Cognitive impairments.
  5. Which of the following imaging findings for MELAS is INCORRECT?
    • [ A ] Stroke-like episodes shows ischemia according to known cerebrovascular distribution.
    • [ B ] Magnetic resonance spectroscopy tends to show a lactate peak and decreased N-acetylaspartate/creatine peak at the location of the lesion.
    • [ C ] Lesions are asymmetric and tend to involve the parietal and occipital lobes.
    • [ D ] Angiographic imaging tends to be normal.
    • [ E ] Ischemic lesions tend to involve the cortex rather than the white matter.

 

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