What is A 48-year-old right-handed man was admitted with a 3-day history of brief generalised tonic-clonic seizures,muscle weakness, a 3-month history of weight loss with increasing difficulty in eating and a 1-week history of word finding difficulties and speech apraxia with reduced fine motor skills.He had a diagnosis of type 2 diabetes mellitus, epilepsy and a history of a left temporal lobe infarct 3 years ago. MRI of the brain showing bilateral coical-based signal abnormality with associated oedema, with corresponding diffusion hyperintensity. MR spectroscopy showing a lactate doublet peak. HPE of muscle biopsy was shown below.What is the most probable diagnosis? and explain in detail?
The clinical scenario shows a child who had normal development previously and then presenting with symptoms of lactic acidosis and stroke(seizures with focal neurological deficits). The microscopy of muscle biopsy with modified Gomori trichrome staining shows ragged red fibers (arrowhead). Based on these features, the child is probably suffering from mitochondrial encephalopathy, lactic acidosis, and stroke (MELAS), which is a mitochondrial inherited condition due to complex I or complex IV deficiency. Treatment options for MELAS are limited and largely focus on suppoive therapy. Reference: Harpers illustrated biochemistry 30th edition