Mitochondrial Encephalomyopathy With Lactic Acidosis and Stroke-Like Episodes (MELAS): An Overview

Introduction:

Mitochondrial Encephalomyopathy With Lactic Acidosis and Stroke-Like Episodes, commonly known as MELAS syndrome, is a complex mitochondrial disorder that affects various systems in the body. Although a rare condition, it is one of the most common mitochondrial disorders that impacts the mitochondria of cells. MELAS syndrome poses significant challenges in diagnosis, management, and prognosis. This article briefly explains MELAS syndrome, including its causes, symptoms, diagnosis, complications, treatment, and prognosis.

What Is MELAS Syndrome?

MELAS stands for mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes, also known as MELAS syndrome. MELAS syndrome is a rare genetic disease that begins in childhood or early adulthood, primarily affecting the nervous system and muscles. The condition is caused by a change in genes that help to create mitochondria, impairing the function of mitochondria, particularly in tissues with high energy demands, such as the brain, muscles, and heart. Mitochondria is a cell structure that converts food into energy, and a by-product of this process is lactic acid. MELAS syndrome causes the buildup of lactic acid in the body (lactic acidosis) and also results in stroke-like symptoms.

Who Gets MELAS Syndrome?

MELAS syndrome is a common mitochondrial disease that affects 1 in 4000 people. Both men and women are equally affected, but only women can pass the condition on to their children.

What Causes MELAS Syndrome?

MELAS syndrome is caused by a change in genes that help to create mitochondria. Mitochondria are essential organelles responsible for producing energy for cellular functions. Within each cell, there can be hundreds to thousands of mitochondria. This mutation leads to impaired energy production and mitochondrial dysfunction, particularly in tissues with high energy demands, such as the brain, muscles, and heart.

What Are the Risk Factors of MELAS Syndrome?

Individuals who have a family history of MELAS syndrome, particularly those with an affected mother who has MELAS syndrome, are at an increased risk of developing the condition.

What Are the Symptoms of MELAS Syndrome?

Symptoms of MELAS syndrome may vary depending on the area of the body affected. Symptoms include:

• Short stature.

• Anorexia.

• Seizures.

• Hallucinations.

• Changes in behavior.

• Vomiting.

• Abdominal pain.

• Fatigue.

• Muscle weakness.

• Difficulty breathing.

The condition is also linked with stroke-like episodes which may present with the following symptoms:

• Severe headache.

• Weakness or numbness of an arm or leg or one side of the body.

• Vision problems in one eye or both eyes.

• Dizziness.

• Slurred speech.

• Imbalance and falling.

• Confusion.

How Is MELAS Syndrome Diagnosed?

Diagnosis of MELAS syndrome involves physical examination, medical history, and diagnostic tests.

1. Physical Examination and Medical History: The physician may inquire about family history and symptoms such as stroke-like episodes, muscle weakness, headache, and other symptoms associated with MELAS syndrome.

2. Diagnostic Test:

• Biochemical Analysis: The increased level of lactic acid in blood and cerebrospinal fluid is the hallmark feature of MELAS syndrome.

• Genetic Testing: Genetic testing is the only way to diagnose MELAS positively.

• Magnetic Resonance Imaging (MRI): Magnetic resonance imaging (MRI) is a useful diagnostic tool for identifying characteristic findings associated with MELAS syndrome during stroke-like episodes.

• Magnetic Resonance Spectroscopy (MRS): This test is used to detect lactate peaks in the brain.

• Muscle Biopsy: in some cases, muscle biopsy is performed. During this procedure, a needle is used to take a small amount of tissue, which is studied under a microscope. If the individual has MELAS syndrome, ragged red fibers are seen in biopsy tissue.

What Are the Complications of MELAS Syndrome?

MELAS syndrome can lead to serious medical complications, such as:

• Cardiac failure.

• Pulmonary embolism.

• Renal failure.

• Aspiration pneumonia.

What Is the Treatment of MELAS Syndrome?

There is no treatment for MELAS syndrome. However, some treatment options can help manage the symptoms and improve the quality of life for patients with this condition. These treatments focus on symptomatic relief, which include:

• Anticonvulsant Medications: Seizures in MELAS syndrome are often managed with anticonvulsant medications. However, caution should be taken with certain drugs like Valproate, which may exacerbate MELAS-related epilepsy in some cases.

• Cochlear Implants: these are the electronic devices that are used to treat deafness.

• Coenzyme Q10 or L-Carnitine: Vitamins such as coenzyme Q10 or L-carnitine can decrease the effects of the illness and enhance energy production by mitochondria.

• L-Arginine: L-arginine might be used during acute events to minimize brain damage, reducing the frequency of stroke-like episodes in MELAS patients.

• Physical Therapy: Physical therapy is given to improve muscle function and stability

• Genetic Counseling: Since MELAS syndrome is a genetic disorder, genetic counseling may be beneficial for affected individuals and their families to know the pattern of inheritance of the condition and make informed choices about family planning.

What Is the Differential Diagnosis of MELAS Syndrome?

MELAS syndrome may present symptoms that are similar to other conditions

1. Kearns-Sayre: this condition shares the same symptoms as that of MELAS syndrome but has some other distinctive features like:

• Chronic progressive external ophthalmoplegia (Eye movement weakness)

• Atypical retinitis pigmentosa (Abnormal pigmentation in the retina)

• Pigment loss in the retina

2. Myoclonus Epilepsy Associated With Ragged Red Fibers (MERRF): This condition is often confused with MELAS syndrome as they both involve seizures, mental deterioration, and myopathy with ragged red fibers on biopsy.

3. Leigh Syndrome: the condition also presents with seizures, and vomiting mainly in young children. Although it shares some symptoms with MELAS syndrome, the age of onset and specific features are different.

What Is the Prognosis of MELAS Syndrome?

The severity of MELAS syndrome varies significantly between individuals. The overall prognosis of MELAS is poor. Since there is no cure for the disease, supportive therapies can improve the quality of life and potentially slow progression.

Conclusion:

MELAS syndrome is a rare and complex mitochondrial disorder characterized by migraine-like headaches, muscle weakness, and stroke-like episodes. The conditions provide various challenges in diagnosis, management, and prognosis as there is no cure for the disease. The current treatment focuses on symptom management. Supportive care like medications, vitamins such as coenzyme Q10 or L-carnitine, genetic counseling, and physical therapy may improve the quality of life of individuals suffering from this condition. Ongoing research may offer hope for improving the outcomes of the condition.