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Mitochondrial encephalomyopathy — RACP Paediatrics MCQ

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HardGenetics and metabolicMitochondrial encephalomyopathyRACP Paediatrics

A 10-year-old has recurrent episodes of vomiting, ptosis and exercise intolerance. Lactate is persistently elevated and MRI during one episode shows cortical signal change not confined to a vascular territory. His mother has hearing loss. What is the most likely diagnosis?

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Correct answer: B — Mitochondrial encephalomyopathy

Multisystem disease with maternal inheritance clues, lactic acidosis and stroke-like MRI lesions not respecting vascular territories suggests mitochondrial encephalomyopathy. Carotid dissection would usually cause a vascular-territory infarct and does not explain chronic ptosis and maternal hearing loss. The pearl is that mitochondrial disease often crosses organ systems, including muscle, brain, hearing and endocrine function.

Reference: RCH Clinical Practice Guidelines; GeneReviews: Mitochondrial disorders