Mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes
Last updated 8 Sept 2020
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Mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes (MELAS) is a condition that affects many of the body's systems, particularly the brain and nervous system (encephalo-) and muscles (myopathy). The signs and symptoms of this disorder most often appear in childhood following a period of normal development, although they can begin at any age. Early symptoms may include muscle weakness and pain, recurrent headaches, loss of appetite, vomiting, and seizures. Most affected individuals experience stroke-like episodes beginning before age 40. These episodes often involve temporary muscle weakness on one side of the body (hemiparesis), altered consciousness, vision abnormalities, seizures, and severe headaches resembling migraines. Repeated stroke-like episodes can progressively damage the brain, leading to vision loss, problems with movement, and a loss of intellectual function (dementia).
Description
Mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes (MELAS) is a condition that affects many of the body's systems, particularly the brain and nervous system (encephalo-) and muscles (myopathy). The signs and symptoms of this disorder most often appear in childhood following a period of normal development, although they can begin at any age. Early symptoms may include muscle weakness and pain, recurrent headaches, loss of appetite, vomiting, and seizures. Most affected individuals experience stroke-like episodes beginning before age 40. These episodes often involve temporary muscle weakness on one side of the body (hemiparesis), altered consciousness, vision abnormalities, seizures, and severe headaches resembling migraines. Repeated stroke-like episodes can progressively damage the brain, leading to vision loss, problems with movement, and a loss of intellectual function (dementia).
Most people with MELAS have a buildup of lactic acid in their bodies, a condition called lactic acidosis. Increased acidity in the blood can lead to vomiting, abdominal pain, extreme tiredness (fatigue), muscle weakness, and difficulty breathing. Less commonly, people with MELAS may experience involuntary muscle spasms (myoclonus), impaired muscle coordination (ataxia), hearing loss, heart and kidney problems, diabetes, and hormonal imbalances.
Inheritance patterns
The source lists the following possible inheritance patterns: mitochondrial. More than one pattern can apply in different cases.
Related genes
Other names
MELAS
MELAS syndrome
Mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes
Mitochondrial myopathy, lactic acidosis, stroke-like episode
Myopathy, mitochondrial-encephalopathy-lactic acidosis-stroke
Related patient information and medicines
Patient information leaflet
Arterial blood gases
Changes in the body cause chemical reactions to occur within the body cells all the time. As part of these reactions, both acid and alkali products will result. Some common causes are listed... Often there may be multiple abnormal processes at work and complex abnormalities may be seen. Causes of metabolic acidosis Build-up of lactic acid, a waste.
Patient information leaflet
Can I take Metformin and Quetiapine together?
Lactic acidosis Metformin can cause a rare but serious build-up of acid in the blood. Dementia in elderly patients There is an increased risk of stroke and death when quetiapine used to treat dementia-related psychosis in elderly patients. Food and drink warnings Alcohol It is best to avoi... Drinking alcohol with this medicine increases the risk.
Patient information leaflet
Can I take Co-codamol and Sukkarto together?
Co-codamol works on pain receptors... Lactic acidosis risk (dehydration) If you develop severe vomiting, diarrhoea, or a high fever, stop taking metformin and contact a doctor immediately. These conditions can lead to severe dehydration, which significantly increases the risk of a rare but life-threatening build-up of acid in the blood (lactic.
Patient information leaflet
Can I take Metformin and Mirtazapine together?
Yo... Lactic acidosis Metformin can cause a rare but serious build-up of acid in the blood. Seek urgent medical help if you experience extreme tiredness, muscle pain, or difficulty breathing. Food and drink warnings Alcohol It is best to avoid or strictly limit alcohol while taking metformin. Drinking alcohol with this medicine increases the risk.
Patient information leaflet
Can I take Metformin and Sertraline together?
Co... Lactic acidosis Metformin can cause a rare but serious build-up of acid in the blood. Seek urgent medical help if you experience extreme tiredness, muscle pain, or difficulty breathing. Food and drink warnings Alcohol It is best to avoid or strictly limit alcohol while taking metformin. Drinking alcohol with this medicine increases the risk.
Patient information leaflet
Can I take Metformin and Semaglutide together?
If you experience severe or persistent stomach upset, speak to your doctor. Important precautions Lactic acidosis Metformin can cause a rare but serious build-up of acid in the blood. Seek urgent medical help if you experience extreme tiredness, muscle pain, or difficulty breathing. Food a... Drinking alcohol with this medicine increases the risk.
Further reading and references
- Mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes; MedlinePlus, National Library of Medicine.
- Betts J, Jaros E, Perry RH, Schaefer AM, Taylor RW, Abdel-All Z, Lightowlers RN, Turnbull DM. Molecular neuropathology of MELAS: level of heteroplasmy in individual neurones and evidence of extensive vascular involvement. Neuropathol Appl Neurobiol. 2006 Aug;32(4):359-73. doi: 10.1111/j.1365-2990.2006.00731.x.
- El-Hattab AW, Almannai M, Scaglia F. MELAS. 2001 Feb 27 [updated 2018 Nov 29]. In: Adam MP, Bick S, Mirzaa GM, Wallace SE, Amemiya A, editors. GeneReviews(R) [Internet]. Seattle (WA): University of Washington, Seattle; 1993-2026. Available from http://www.ncbi.nlm.nih.gov/books/NBK1233/
- Goodfellow JA, Dani K, Stewart W, Santosh C, McLean J, Mulhern S, Razvi S. Mitochondrial myopathy, encephalopathy, lactic acidosis and stroke-like episodes: an important cause of stroke in young people. Postgrad Med J. 2012 Jun;88(1040):326-34. doi: 10.1136/postgradmedj-2011-130326. Epub 2012 Feb 10.
- Matsumoto J, Saver JL, Brennan KC, Ringman JM. Mitochondrial encephalomyopathy with lactic acidosis and stroke (MELAS). Rev Neurol Dis. 2005 Winter;2(1):30-4.
- Sproule DM, Kaufmann P. Mitochondrial encephalopathy, lactic acidosis, and strokelike episodes: basic concepts, clinical phenotype, and therapeutic management of MELAS syndrome. Ann N Y Acad Sci. 2008 Oct;1142:133-58. doi: 10.1196/annals.1444.011.
- Thambisetty M, Newman NJ. Diagnosis and management of MELAS. Expert Rev Mol Diagn. 2004 Sep;4(5):631-44. doi: 10.1586/14737159.4.5.631.
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