Myopathy - An Overview

Introduction

Diseases affecting the skeletal muscles, which attach to bones, are collectively referred to as myopathies. Myopathies can arise later in life (acquired) or be hereditary and passed down via generations. Individuals who have myopathy may find it difficult to do everyday tasks like brushing their hair, taking a shower, or getting out of a chair.

What Is Myopathy?

A group of illnesses known as myopathies target skeletal muscles. These illnesses weaken muscles by attacking the muscular fibers. Myopathies are genetic or acquired disorders that frequently make it difficult to carry out daily activities. Skeletal muscles are the body's muscles attached to the skeleton. They make up the majority of the muscles in the body and are voluntary, so they have control over their actions. However, myopathies can result in various issues with the entire body because skeletal muscles comprise most of the muscles.

What Are the Types of Myopathy?

Myopathies are divided into two groups:

1. Inherited Myopathy: A broad class of muscle illnesses known as hereditary myopathies and muscular dystrophies, includes weakness, motor delay, respiratory and bulbar dysfunction, and other frequent complaints and clinical symptoms. Hereditary myopathies include the following conditions:

• Cognitive Myopathy: Congenital myopathies typically cause symptoms from birth or early childhood; however, they can also manifest in adolescence or even later in adults.

• Mitochondrial Myopathy: A malfunction in the mitochondria, the parts of cells that produce energy, results in mitochondrial myopathy. Muscle weakness is one of the many signs of these ailments. Mitochondrial abnormalities also usually impact other organ systems, such as the heart, brain, and gastrointestinal tract.

• Metabolic Myopathy: Metabolic myopathies are caused by errors in the genes that code for enzymes necessary for healthy muscular contraction and movement.

• Muscular Dystrophies: The progressive deterioration of muscle tissue resulting from aberrant or inadequate structural support proteins is the hallmark of muscular dystrophies.

2. Acquired Myopathies: Acquired myopathies can arise from a variety of causes, including electrolyte imbalances, infections, exposure to specific drugs, and other medical conditions.

• Inflammatory and Immune Myopathies: A class of uncommon disorders known as inflammatory myopathies are characterized by long-term, persistent muscular inflammation, muscle weakening, and, in certain situations, muscle discomfort.

• Autoimmune or Inflammatory Myopathy: Diseases known as autoimmune/inflammatory myopathies occur when the body targets itself, impairing muscular function.

• Myopathy Caused By Toxins: When a poison or drug affects the structure or function of muscles, it can result in toxic myopathy. Alcohol and toluene, a gas found in spray paint and other drugs that substance abusers may inhale, are examples of toxins.

• Endocrine Disorders: Hormones can cause endocrine myopathies, disorders that impair muscle function.

• Thyroid: While hyperthyroidism (high thyroid) can potentially cause issues, hypothyroidism (low thyroid) is more common.

• Parathyroid: Elevated calcium levels due to hyperparathyroidism.

• Adrenal: Cushing syndrome and Addison's illness.

3. Infectious Myopathy

Infections that impair muscle function can lead to infectious myopathies. Among them are:

• Viral diseases such as Epstein-Barr, HIV, and influenza.

• Bacteria-induced pyomyositis.

• Lyme illness.

• Parasitic diseases such as cysticercosis, toxoplasmosis, and trichinosis.

• Fungal diseases such as coccidiomycosis and candida.

• Imbalance of electrolytes.

The following electrolyte levels, either high or low, might affect how muscles contract:

• Potassium.

• Low and high levels of hypokalemia.

• Hypermagnesemia.

• High in magnesium.

• Myopathy in critical illness.

Serious Disease Myopathy: This is a disorder of the limbs and the respiratory muscles, which are responsible for breathing. It occurs when receiving treatment in an intensive care unit. It may be brought on partly by extended immobility from bed rest or by drugs used to treat the patient, such as sedatives, corticosteroids, or muscle relaxants.

What Are the Symptoms of Myopathy?

Common symptoms are present in several myopathies. Among these typical symptoms are:

• Muscle weakness, usually in the legs, shoulders, and upper arms.

• Spasms, cramps, and rigidity in the muscles.

• Exhaustion after a workout.

• Insufficient vigor.

Other specific symptoms are present in some myopathies.

• Muscle weakness in muscular dystrophy progresses over time and frequently starts in the shoulders, hips, and face. An inability to relax a particular muscle may be the initial symptom of several forms of muscular dystrophy.

What Is a Diagnosis of Myopathy?

The doctor will inquire about symptoms, past prescription drug use, and medical and family history. The doctor will check skin, reflexes, muscle strength, balance, and sensitivity during the physical examination. Healthcare practitioners could request the following tests:

• Blood Tests: Certain myopathies cause the breakdown of muscle fibers, so muscle enzymes like creatine kinase (CK) or aldolase may be increased, as well as amounts of electrolytes, including calcium, phosphorus, magnesium, potassium, and sodium.

What Is the Treatment?

Healthcare professionals will identify the exact type of myopathy and create a treatment strategy tailored to individual symptoms. Physical therapy, occupational therapy, and exercise are the mainstays of treatment. Certain therapies vary depending on the kind of myopathy. Most acquired myopathies can generally be effectively managed to reduce symptoms and weakness. Several treatments for some hereditary myopathies can halt the disease's progression. There are no particular treatments for most hereditary myopathies; however, physical therapy and specialized exercise regimens can be beneficial.

1. Autoimmune and Inflammatory Myopathies: The aim of treatment is to reduce inflammation and the body's autoimmune reaction. Often, these myopathies are managed with Methotrexate, Cyclosporine, Tacrolimus, Azathioprine, Mycophenolate, Rituximab, and corticosteroids such as Methylprednisolone and Prednisone.

2. Genetic and Inherited Myopathies: Most hereditary and genetic myopathies have no known cure or treatment. Management focuses on controlling symptoms and utilizing various therapies. Numerous clinical trials investigating treatments and gene therapy are underway in several scientific fields. Certain medications can be used to treat illnesses, including Pompe disease and Duchenne muscular dystrophy.

3. Additional Acquired Myopathies: Medical professionals address the underlying illness that causes the acquired myopathy, such as endocrine, toxic, and viral myopathies. Stopping the offending substance (alcohol, for example) or medicine (Statins, for example) is the treatment for toxin-related myopathies. Antibiotic treatment immediately addresses the infection, causing the muscle symptoms that arise from infections resulting from viruses, bacteria, or other infectious organisms.

Conclusion

A diverse range of illnesses known as myopathies mostly impact skeletal muscle's structure, metabolism, or channel function. Typically, they have muscle weakness that interferes with their day-to-day activities. Additionally, rhabdomyolysis (a rare muscular injury called rhabdomyolysis that causes muscles to break down) is linked to some myopathies, and muscle discomfort is frequently observed.