Myopathy

The medical term used to describe disorders that negatively affect skeletal muscles (the muscles that connect to bones) is myopathy. While some people get this condition from their biological parents, it can also be acquired later in life. Usually, people who experience this condition have problems with daily activities, including bathing, combing their hair, standing up from a chair, and others.

Types of Myopathy

Healthcare professionals have divided this condition into 2 categories based on the cause. For example, inherited myopathies and acquired myopathies.

Inherited Myopathies

The following types happen when children get an abnormal gene from their biological parents. These include:

Congenital myopathies – Commonly, people with this type of inherited myopathy begin to experience symptoms at birth or in early childhood. In rare cases, the symptoms may not appear until the teen years or later adulthood. In general, congenital myopathy is considered unique compared to other types of inherited myopathy because it negatively affects all muscles and is not progressive.
Mitochondrial myopathies – In such cases, muscle weakness occurs due to an error in the mitochondria. These are energy-producing parts of a cell. This type of inherited myopathy often affects the muscles, but may also impact the heart, brain, and gastrointestinal tract.
Metabolic myopathies – This form of inherited myopathy often happens due to defective genes that code for enzymes required for normal muscle function and movement. People with a metabolic myopathy cannot perform physical activity.
Muscular dystrophies – These conditions cause progressive degeneration of muscles. Usually, it occurs due to abnormal or a lack of structural support proteins.

Acquired Myopathies

The following types of myopathy usually occur later in life. Other disorders, infections, prolonged exposure to certain medicines, and electrolyte imbalances can cause acquired myopathies.

Autoimmune Myopathy

In such cases, the condition occurs because the immune system mistakenly attacks the muscles instead of viruses, bacteria, and other germs that can make you ill.

Toxic Myopathy

This type of myopathy happens due to a toxin or medicine that negatively affects the muscle structure. For example:

Toxins – Tolurene (a vapor in spray paint), alcohol, and others.
Medicines – Corticosteroids (such as Prednisone), statins (cholesterol-lowering medicines), checkpoint inhibitor immunotherapy (including Nivolumab and Pembrolizumab), Colchicine, Chloroquine, antiviral drugs, protease inhibitors (used to treat HIV infection), Omeprazole, and others.

Endocrine Myopathy

This type of myopathy happens when certain hormones interfere with the muscle function. For example:

Thyroid – Hypothyroidism (underactive thyroid gland) or hyperthyroidism (overactive thyroid gland).
Parathyroid – Increased Calcium levels in the blood may also affect muscle function. It often occurs due to hyperparathyroidism (overactive parathyroid glands).
Adrenal – Usually, the muscles are affected by an underlying disorder. For example, Cushing syndrome, Addison’s disease, and others.

Infectious Myopathy

This type of myopathy happens due to an infection that affects the muscles. Check some examples below:

Lyme disease
Bacterial pyomyositis
Viral infections (including HIV, Epstein-Barr, influenza)
Parasitic infections (such as toxoplasmosis, cysticercosis, or trichinosis)
Fungal infections (such as Candida, Coccidiomycosis, and others)

Electrolyte Imbalance Myopathy

In some cases, myopathy may occur due to an electrolyte imbalance. These include hypokalemia (reduced Potassium levels in the blood), hyperkalemia (increased Potassium levels in the blood), or hypermagnesemia (increased Magnesium levels in the blood).

Critical Illness Myopathy

This form of myopathy is a disease that negatively affects the limbs and the muscles that help you breathe (also known as the respiratory muscles). While it happens, a person is cared for in an intensive care unit, it may also occur due to prolonged immobility, or by a medicine that is used during your care. These include corticosteroids, sedatives, or muscle relaxants.

What Are The Symptoms of Myopathy?

Usually, people with myopathy experience the following symptoms. Check some general symptoms below:

Muscle weakness (one of the most common symptoms of myopathy, and it often affects the upper arms, shoulders, and thighs)
Muscle stiffness, spasms, and cramps
Lack of energy
Extreme tiredness (fatigue)
Difficulty performing daily activities (including bathing, dressing, and others)
Dyspnea (shortness of breath)
Trouble getting out of a chair, climbing stairs, and others.
Problems with speech and swallowing

If any of the previous symptoms occur, immediately contact your healthcare professional.

Risk Factors

This condition can affect anyone, but the following factors can increase the risk even more. For example:

Family history – The risk of developing myopathy significantly increases if you have a parent or sibling with this condition.
Sex – Males are more likely to develop myopathy than females.
Autoimmune, metabolic, or endocrine disorders
Long-term exposure to some medicines or toxins

How Common is Myopathy?

Generally, this condition happens rarely, but it depends on the type. For instance, endocrine and inflammatory myopathies are more common than other and they often affect mostly women. Moreover, approximately 25% to 80% of people with an underactive thyroid gland also develop myopathy. The most common types of myopathy are Duchenne’s and Becker’s muscular dystrophies, and they affect about 7 per 100,000 people worldwide.

Diagnosis

Usually, the diagnosis of myopathy starts with a physical examination in which doctors check for abnormalities linked to the disease. Thereafter, they will ask some questions about the symptoms and medical history to gather more information about your disease. In any case, to exclude or confirm this disease, your physician may perform the following tests. These include:

Blood tests – These tests are done to check for muscle enzymes (such as creatine kinase or aldolase), electrolyte levels (including phosphorus, calcium, potassium, sodium, and others), autoimmune disorders, and hormone levels.
Electromyography (EMG) – This test also includes examination of the electrical conduction of the nerves.
MRI (magnetic resonance imaging) scans
Genetic tests
Muscle biopsy – During this procedure, doctors will take a small amount of the affected muscle for testing.

Treatment

Usually, physicians prescribe different treatments for people with myopathy because they depend on several factors. Examples include the severity and type of the condition, overall health, age, gender, and preferences. While all people with myopathy need physical and occupational therapy, doctors may prescribe more specific options.

Autoimmune-Related Myopathy Treatment

In such cases, the treatment goal is to relieve the symptoms and prevent serious complications. Physicians often prescribe:

Immunosuppressants (such as Methotrexate, Cyclosporine, Tacrolimus, Azathioprine, Mycophenolate, Rituximab, and intravenous or subcutaneous immunoglobulin)
Corticosteroids (such as Prednisone or Methylprenisolone) to reduce inflammation.

Inherited and Genetic Myopathy Treatment

Usually, these myopathies do not have specific treatments or a cure. That’s why the goal of the treatment is to manage the symptoms, prevent life-threatening complications, and improve your quality of life. Usually, doctors prescribe specific medicines (especially for Duchenne muscular dystrophy and Pompe disease), gene therapy, and clinical trials.

Acquired Myopathy Treatment

Usually, acquired myopathy occurs due to an underlying condition, and treating it often helps get rid of the symptoms. Doctors may prescribe antivirals, antibiotics, anti-fungal medicines, or recommend stopping the medicine or the offending agent (including alcohol) that causes it.

Frequently Asked Questions

How do I take care of myself?

Doctors often recommend the following tips to manage the condition. For example:

Physical exercise – You should aim for 30 minutes of physical exercise, at least 5 days a week. It also helps get or maintain a healthy weight.
Dietary changes – Add to your diet more fresh fruits, vegetables, and whole grains.
Use a sunscreen with an SPF (sun-protective factor) of at least 30, especially when outdoors.
Administer the medicines exactly as recommended by your doctor (especially antibiotics).

What are myopathy symptoms?

Commonly, people with this condition experience the following symptoms. These include progressive and symmetric muscle weakness, movement problems, fatigue (extreme tiredness), pain, and delayed motor skills.

What is the life expectancy of a person with myopathy?

In general, the life expectancy varies among people with myopathy. It often ranges from a full lifespan to a significantly shortened one.

Can myopathy be cured?

The possibility of a cure depends on the type of myopathy. Some acquired forms may improve or resolve when the underlying cause is treated. However, many inherited myopathies do not currently have a cure, and treatment focuses on managing symptoms, maintaining muscle function, and improving quality of life.

What causes myopathy?

Myopathy can be caused by inherited genetic mutations, autoimmune diseases, hormonal disorders, infections, electrolyte imbalances, exposure to toxins, certain medications, or critical illnesses. In some cases, the exact cause may be difficult to identify.

Is myopathy the same as muscular dystrophy?

No. Myopathy is a broad term that refers to diseases affecting the muscles, while muscular dystrophy is a specific group of inherited myopathies that cause progressive muscle weakness and degeneration over time.

Can exercise help people with myopathy?

Yes, appropriate exercise can help maintain muscle strength, flexibility, and overall physical function. Exercise programs should be tailored to the individual’s condition and supervised by a healthcare professional to avoid overexertion and muscle damage.

Can myopathy affect breathing?

Yes. Certain forms of myopathy can weaken the respiratory muscles, making breathing more difficult. People may experience shortness of breath, especially during physical activity or while lying down. Severe cases may require specialized respiratory support.

Does myopathy affect the heart?

Some types of myopathy, particularly certain inherited forms such as mitochondrial myopathies and muscular dystrophies, can affect the heart muscle. This may lead to heart rhythm abnormalities or cardiomyopathy, making regular cardiac evaluations important.

When should I see a doctor about muscle weakness?

You should contact a healthcare professional if you experience unexplained muscle weakness, difficulty climbing stairs, frequent falls, trouble swallowing, breathing difficulties, or symptoms that gradually worsen over time. Early diagnosis and treatment may help prevent complications. Ask your healthcare provider if you have additional questions.