Myopathy Causes, Symptoms, and Treatment

Myopathy refers to diseases of the muscles that connect to the bones (skeletal muscles). The symptoms of myopathy include muscle weakness, stiffness, and cramps.

If you have been diagnosed with myopathy, or if you are currently being evaluated for possible myopathy, there is a strong chance that you have not heard about myopathy until now, because it is not as common as other medical conditions.

This article covers how myopathy is diagnosed, what to anticipate in terms of prognosis and treatment, and whether other members of your family might also be at risk of myopathy.

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Myopathy refers to a disease of the muscles. In these cases, the muscles work less effectively than they should. That can occur when the muscles do not develop properly, when they have become damaged, or when they are lacking important components.

Muscles normally work by contracting, which means becoming shorter. A muscle is composed of proteins and other structural components that move in a coordinated manner to contract the muscle. When any of these components is defective, this may cause myopathy.

There are a number of different causes of muscle disease, and consequently, there are a number of different myopathies. Each of the different myopathies has its own specific name, cause, set of diagnostic tests, anticipated prognosis, and treatment.

Some myopathies are expected to worsen over time, while some are fairly stable. Several myopathies are hereditary, and many are not.

Types of Myopathy

Congenital myopathy means myopathy that a person is born with. Many of these conditions are believed to be hereditary and passed on from parents to children through genetics.

While the symptoms of congenital myopathies often begin at a very young age, that is not always the case. Sometimes a hereditary medical illness does not begin to produce symptoms until a person is a teenager or even an adult.


Inherited myopathies include:

  • Mitochondrial myopathy: This is a disease caused by a defect in the energy-producing part of the cell, the mitochondria. There are several types of mitochondrial myopathy. While they can be caused by hereditary mutations (abnormalities in the genes) they can also occur without any family history.
  • Metabolic myopathy: This group of diseases is caused by metabolic problems that interfere with muscle function. There are a number of hereditary metabolic myopathies caused by defects in the genes that code for certain enzymes that are necessary for normal muscle movement.
  • Nemaline myopathy: This is a group of disorders characterized by the presence of structures called "nemaline rods" in the muscles. Nemaline myopathy is often associated with respiratory muscle weakness.


Congenital myopathies include:

  • Central core myopathy: This is a hereditary myopathy, also called central core disease, that causes weakness, bone problems, and severe reactions to some medications. The severity of this disease varies, causing profound weakness among some people and only mild weakness in others.
  • Muscular dystrophy: This is a group of diseases caused by degeneration of the muscles or abnormally formed muscle cells. Technically, muscular dystrophy is not myopathy, but there is often overlap in the symptoms, and initial evaluation aims to determine which you have.

The main difference between myopathy and muscular dystrophy is that muscles do not function properly in myopathy, whereas the muscles degenerate in muscular dystrophy.


Myopathy can also be caused by a variety of illnesses that produce a range of physical problems in addition to issues with muscle contraction.

Commonly acquired myopathies include:

  • Inflammatory/ autoimmune myopathy: This occurs when the body attacks itself, causing muscle degeneration or interfering with function. Myopathies characterized by inflammation in or near the muscle include polymyositis, dermatomyositis, sarcoidosis, lupus, and rheumatoid arthritis.
  • Toxic myopathy: This occurs when a toxin, a medication, or a drug impairs muscle structure or function.
  • Endocrine myopathy: This occurs when a disorder of the hormones interferes with muscle function. The most common causes include thyroid or adrenal gland problems.
  • Infectious myopathy: This may happen when an infection prevents the muscles from functioning properly.
  • Myopathy secondary to electrolyte imbalance: Electrolyte problems, such as excessively high or low potassium levels, can interfere with the function of the muscles.

Myopathy Symptoms

In general, myopathy causes muscle weakness. The most common pattern of weakness is proximal weakness. This means that the muscles of the upper arms and upper legs are more obviously weakened than the muscles of the hands or feet.

Sometimes, myopathy weakens the respiratory muscles (muscles that control breathing).

Often, when people have had myopathy for years, muscle atrophy begins to develop. This is a thinning out and wasting away of muscles that further weakens them.

Myopathy is often associated with the abnormal shape of the bones, often because the muscles don't adequately support the bones.

Other characteristics of myopathy include fatigue, lack of energy, and worsening weakness as the day goes on, or progressive weakness with exertion.


In general, it can take a while to be diagnosed with myopathy. If you have symptoms of myopathy, there is a strong chance that you will get a referral to a neurologist or a rheumatologist, or both, depending on which of your symptoms is most prominent.

Diagnostic testing includes a careful physical evaluation, including examination of your skin, reflexes, muscle strength, balance, and sensation. Your healthcare provider will take a detailed medical history and ask you about your family's medical history.

There are also a number of tests that you may need, depending on your medical history and the findings of your physical examination. These tests include blood tests, such as a complete blood count (CBC) and electrolyte levels.

Other blood tests include erythrocyte sedimentation rate (ESR), which measures inflammation, and the antinuclear antibody test (ANA), which looks for autoimmune activity. Creatine kinase in the blood can evaluate muscle breakdown. Thyroid tests, metabolic, and endocrine tests may be needed.

Another test called an electromyography (EMG) is an electrical test that assesses muscle function through the use of needles that detect several characteristics of your muscle structure and movement. Sometimes, specialized tests such as muscle biopsy and genetic testing can help diagnose certain types of myopathy.


When there is an identifiable cause, such as an endocrine problem, correcting the cause can help improve the symptoms of myopathy and prevent it from worsening.

Often, respiratory support is the key component in advanced myopathy, so that your breathing can be safely maintained.


In general, congenital myopathy is expected to worsen or stabilize over time and is not typically expected to improve. The myopathies that are not congenital, such as infectious, metabolic, or toxic myopathies, may improve once the cause of the myopathy is well controlled.

If you have a type of myopathy that is not expected to improve, you should pay close attention to issues such as atrophy, pressure sores, and making sure that you maintain optimal participation in physical therapy so that you can function at your best.

Is Myopathy Hereditary?

Yes, some myopathies are hereditary. If you have a hereditary myopathy, then there is a chance that some of your siblings, children, nieces, and nephews, or other relatives could also develop myopathy.

It is important to let your family know about your condition, as an early diagnosis can help them get earlier treatment and supportive care.

A Word From Verywell

Myopathy is not a very common condition. Muscle disease can impair your quality of life. However, many individuals who are diagnosed with myopathy are able to maintain productive lives, including hobbies, physical activities, maintaining satisfying employment, and enjoying a happy family and social life.

Frequently Asked Questions

  • Is there a cure for myopathy?

    No, there is not a cure for myopathy itself. However, it can be treated to improve symptoms. If myopathy is related to an illness, like a virus or electrolyte imbalance, the muscle symptoms will improve when the underlying condition resolves. Immunosuppressants can help relieve symptoms of certain types of myopathy. With many types of chronic myopathy, support such as physical and occupational therapy, dietary management, and speech or swallow therapy is crucial.

  • What causes mitochondrial myopathy?

    Mitochondrial myopathy is caused by genetic mutations. Mitochondrial myopathy affects a cell’s ability to manufacture adenosine triphosphate (ATP), which provides energy for actions such as muscle contraction. When muscles are deprived of ATP, they become fatigued and may be permanently damaged.

11 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. National Institute of Neurological Disorders and Stroke. Mitochondrial myopathy fact sheet.

  2. Tarnopolsky MA. Metabolic myopathies. Continuum (Minneap Minn). 2016;22(6):1829-1851. doi:10.1212/CON.0000000000000403

  3. Genetic and Rare Diseases Information Center (NIH). Nemaline myopathy.

  4. Genetic and Rare Diseases Information Center (NIH). Central core disease.

  5. National Institute of Neurological Disorders and Stroke. Muscular dystrophy information page.

  6. Lundberg IE, Miller FW, Tjärnlund A, Bottai M. Diagnosis and classification of idiopathic inflammatory myopathies. Intern Med. 2016;280(1):39-51. doi:10.1111/joim.12524

  7. Pasnoor M, Barohn RJ, Dimachkie MM. Toxic myopathies. Neurol Clin. 2014;32(3):647-70, viii. doi:10.1016/j.ncl.2014.04.009

  8. Katzberg HD, Kassardjian CD. Toxic and endocrine myopathies. Continuum (Minneap Minn). 2016;22(6):1815-1828. doi:10.1212/CON.0000000000000407

  9. Chawla J. Stepwise approach to myopathy in systemic disease. Front Neurol. 2011;2:49. doi:10.3389/fneur.2011.00049

  10. National Institute of Neurological Disorders and Stroke. Myopathy information page.

  11. National Institute of Neurological Disorders and Stroke. Mitochondrial myopathy fact sheet.

By Heidi Moawad, MD
Heidi Moawad is a neurologist and expert in the field of brain health and neurological disorders. Dr. Moawad regularly writes and edits health and career content for medical books and publications.