MELAS (Mitochondrial Encephalomyopathy, Lactic Acidosis, and Stroke-like Episodes)

What this deck covers

MELAS (Mitochondrial Encephalomyopathy, Lactic Acidosis, and Stroke-like Episodes) in eighteen clinical teaching cases with worked explanations. Each case gives you a clinical vignette, four options, the correct answer, and an explanation of why each of the other three is wrong.

Diagnoses and management options tested

Across the eighteen cases you are asked to choose between options such as: Seizures, intellectual disability and hypotonia, Ophthalmoplegia, retinitis pigmentosa and cardiac block, Myoclonic epilepsy, ataxia and ragged-red fibres, Before 2 years of age, 15 to 40 years of age, After 40 years of age, Lesions follow the middle cerebral artery territory, Lesions do NOT conform to vascular territories, Proximal muscle weakness with exercise intolerance, Distal muscle wasting with foot drop, Fasciculations and hyperreflexia, Facial diplegia and ptosis, m.3243A>G in the MTTL1 gene, m.8344A>G in the MTTK gene, Deletion of mtDNA segments of 4–5 kb, m.3271T>C in the MTTL1 gene, Defective lysosomal enzyme activity, Abnormal peroxisomal fatty acid oxidation, Impaired oxidative phosphorylation and ATP production, Deficiency of cytoplasmic ribosomes, Elevated lactate:pyruvate ratio in serum and CSF, Decreased serum glucose with ketonaemia, Elevated serum ammonia with normal lactate, Elevated serum creatinine with proteinuria, Cerebrospinal fluid (CSF), Peripheral blood lymphocytes only.

Clinical pearls from this deck

• The name is the triad: encephalomyopathy (seizures, dementia, altered consciousness), lactic acidosis from the shift to anaerobic glycolysis, and stroke-like episodes producing hemiparesis and hemianopia by a non-vascular mechanism.
• MELAS typically manifests between 2 and 15 years, with peak onset in the school-age years — and crucially after a period of entirely normal early development.

The eighteen worked cases in this deck, with the images and the full explanation of every option, are part of Pediatric Case Review membership. See what is included.

More from this system: all metabolic and genetic decks and question sets · pediatric reference values.