Mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes

Mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes
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Synonyms	MELAS syndrome
Pronounce
Specialty	Neurology, Genetics
Symptoms	Muscle weakness, headaches, loss of appetite, vomiting, seizures, stroke-like episodes
Complications
Onset	Typically before age 40
Duration	Long-term
Types
Causes	Genetic mutations (mostly in mitochondrial DNA)
Risks	Family history
Diagnosis	Muscle biopsy, genetic testing, MRI
Differential diagnosis	MERRF syndrome, Leigh syndrome, Alpers' syndrome
Prevention
Treatment	Supportive care, vitamins, coenzyme Q10
Medication
Prognosis	Variable
Frequency	Rare
Deaths

Mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes (MELAS) is a rare genetic disorder that affects the body's ability to produce energy at the cellular level. It is one of the most frequently encountered mitochondrial diseases and is characterized by a variety of symptoms including muscle weakness, neurological impairments, and episodic crises often described as stroke-like episodes.

Symptoms and Signs

MELAS syndrome presents a range of symptoms, which typically begin in childhood but can start at any age before 40. The hallmark features include:

• Muscle Weakness and Pain
• Neurological Impairments: Seizures, migraines, and cognitive decline.
• Stroke-like Episodes: Sudden episodes resembling strokes, including hemiparesis, altered consciousness, and visual disturbances.
• Lactic Acidosis: An abnormal buildup of lactic acid in the body, leading to nausea, vomiting, abdominal pain, and rapid breathing.

Causes

MELAS is primarily caused by mutations in the mitochondrial DNA, which are inherited in a matrilineal fashion. The most common mutation associated with MELAS is the m.3243A>G mutation in the MT-TL1 gene, which affects mitochondrial protein synthesis.

Diagnosis

Diagnosis of MELAS involves a combination of clinical evaluation, laboratory testing, and imaging studies. Key diagnostic tools include:

• Muscle Biopsy: Revealing ragged-red fibers indicative of mitochondrial abnormalities.
• Genetic Testing: Identifying specific mitochondrial DNA mutations.
• Magnetic Resonance Imaging (MRI): Showing stroke-like changes not confined to vascular territories.

Treatment and Management

There is no cure for MELAS, and treatment focuses on managing symptoms and slowing progression of the disease. Management strategies include:

• Supportive Care: Physical therapy, occupational therapy, and nutritional support.
• Medications: Anticonvulsants for seizures, pain relievers, and potentially Coenzyme Q10 and other vitamins to support mitochondrial function.

Prognosis

The prognosis for individuals with MELAS varies widely and depends on the severity of symptoms and the age of onset. The disease progression is unpredictable, with periods of stability interspersed with acute declines associated with stroke-like episodes.

Epidemiology

MELAS is a rare condition, though its exact prevalence is unknown. It is one of the more common mitochondrial disorders and can affect individuals of any ethnic background.

See Also

• Mitochondrial disease
• Leigh syndrome
• Kearns-Sayre syndrome
• Neuromuscular disease