Case Of the Week (COW) 16 August 2015
MELAS
Findings
Multiple chronic infarcts involving bilateral gangliocapsular region , pons and corpus callosum Acute infarct involving right centrum semiovale region with slightly high ADC values ( 1.3x 10-3 mm2/s) Basal ganglia calcification Few microhemmorhages in the bilateral parietal lobe whitematter Spectroscopy- increased lactate levels
Discussion
The clinical diagnosis of MELAS is based on the following features: 1) encephalopathy with seizures and/or dementia, 2) stroke-like episodes occurring before the age of 40, 3) the presence of lactic acidosis, ragged red muscle fibres Additional criteria Recurrent headaches Recurrent vomiting CT Multiple infarcts involving multiple vascular territories may be either symmetrical or asymmetrical parieto-occipital and parieto-temporal involvement is most common Basal ganglial calcification -more prominent feature in older patients Atrophy MRI Acute infarcts Swollen gyri with increased T2 signal Mass effect May enhance Subcortical white matter involved Increased signal on DWI (T2 shine through) with little if any change on ADC: thought to represent vasogenic rather than cytotoxic oedema Chronic infarcts Involving multiple vascular territories May be either symmetrical or asymmetrical Parieto-occipital and parieto-temporal most common MR Spectroscopy May demonstrate elevated lactate peak at 1.3 ppm in otherwise normal appearing brain parenchyma or in CSF Decreased NAA spectrum and decreased NAA/Cr ratio Choline/Cr ratio was normal. This case is submitted to emphasise the role of MRI in diagnosing MELAS and guide the physician for mitochondrial DNA deletion analysis as early diagnosis leads to early treatment with succinate and arginine will reduce further morbidity.
Contributed By:
Prof. S Babu Peter, Dr. S. Arunprasad
Barnard Institute of Radiology
MELAS
Findings
Multiple chronic infarcts involving bilateral gangliocapsular region , pons and corpus callosum Acute infarct involving right centrum semiovale region with slightly high ADC values ( 1.3x 10-3 mm2/s) Basal ganglia calcification Few microhemmorhages in the bilateral parietal lobe whitematter Spectroscopy- increased lactate levels
Discussion
The clinical diagnosis of MELAS is based on the following features: 1) encephalopathy with seizures and/or dementia, 2) stroke-like episodes occurring before the age of 40, 3) the presence of lactic acidosis, ragged red muscle fibres Additional criteria Recurrent headaches Recurrent vomiting CT Multiple infarcts involving multiple vascular territories may be either symmetrical or asymmetrical parieto-occipital and parieto-temporal involvement is most common Basal ganglial calcification -more prominent feature in older patients Atrophy MRI Acute infarcts Swollen gyri with increased T2 signal Mass effect May enhance Subcortical white matter involved Increased signal on DWI (T2 shine through) with little if any change on ADC: thought to represent vasogenic rather than cytotoxic oedema Chronic infarcts Involving multiple vascular territories May be either symmetrical or asymmetrical Parieto-occipital and parieto-temporal most common MR Spectroscopy May demonstrate elevated lactate peak at 1.3 ppm in otherwise normal appearing brain parenchyma or in CSF Decreased NAA spectrum and decreased NAA/Cr ratio Choline/Cr ratio was normal. This case is submitted to emphasise the role of MRI in diagnosing MELAS and guide the physician for mitochondrial DNA deletion analysis as early diagnosis leads to early treatment with succinate and arginine will reduce further morbidity.
Contributed By:
Prof. S Babu Peter, Dr. S. Arunprasad
Barnard Institute of Radiology