From the Guidelines
Mitochondrial Encephalomyopathy, Lactic Acidosis, and Stroke-like episodes (MELAS) is a rare genetic disorder characterized by exercise intolerance, onset before 40 years of age, seizures, ragged-red fibers, lactic acidosis, and stroke-like manifestations. The cardinal features of MELAS include a combination of these symptoms, with many individuals also experiencing migraine-like headaches 1. The disorder is likely caused by altered cellular metabolism resulting in small cerebral vessels that impede blood flow to the affected cortex or indirectly owing to dysfunction of autoregulatory mechanisms 1. Key characteristics of MELAS include:
- Onset before 40 years of age
- Seizures
- Ragged-red fibers
- Lactic acidosis
- Stroke-like manifestations
- Migraine-like headaches Various interventions have been tried for MELAS, including coenzyme Q10, L-carnitine, idebenone, dichloracetate, vitamin C, riboflavins, and corticosteroids, but none of these is clearly effective 1. However, a recent study suggested that the nitric oxide precursor L-arginine may improve endothelial function in individuals with MELAS 1. The blood leukocyte DNA reveals the A3243G mutation in 80% of MELAS patients, which can aid in diagnosis 1. Management of MELAS focuses on symptom management rather than cure, and patients should be monitored by a multidisciplinary team due to the disorder's impact on multiple organ systems 1.
From the Research
Definition and Characteristics of MELAS Syndrome
- Mitochondrial Encephalomyopathy, Lactic Acidosis, and Stroke-like episodes (MELAS) syndrome is a rare neurodegenerative disease caused by the decreased ability of cells to produce sufficient energy in the form of adenosine 5'-triphosphate 2.
- It is one of the most common maternally inherited mitochondrial disorders, with a broad range of clinical manifestations and a highly variable course 2.
- The classic neurologic characteristics include encephalopathy, seizures, and stroke-like episodes 2.
Clinical Manifestations and Multisystem Effects
- In addition to its neurologic manifestations, MELAS syndrome exhibits multisystem effects including cardiac conduction defects, diabetes mellitus, short stature, myopathy, and gastrointestinal disturbances 2.
- Patients with MELAS syndrome may also experience metabolic derailment, especially in situations with increased stress, due to impaired mitochondrial energy production and subsequent lactic acidosis 3.
- Endocrine disorders, such as growth hormone deficiency and diabetes, may be one of the first manifestations of MELAS syndrome 4.
Treatment and Management
- There is currently no curative therapy for MELAS, and treatment focuses on managing complications that affect specific organs and functions 5.
- Many of the accepted therapies used in treating MELAS syndrome have been identified through a small number of clinical trials or isolated case reports, and include antioxidants and various vitamins aimed at minimizing the demands on the mitochondria and supporting and maximizing their function 2.
- Intraoperative parenteral nutrition may be used to counteract the formation of lactic acidosis in patients with MELAS syndrome undergoing anesthesia 3.
- Immunonutrients can be used as a therapeutic alternative in patients with MELAS syndrome 5.