Everything You Need to Know About Myopathy

Medically Reviewed By Meredith Goodwin, MD, FAAFP

“Myopathy” refers to the diseases and disorders that affect the muscles. There are many different causes and symptoms. However, the most common symptoms are muscle weakness and fatigue. Myopathy means “disease of muscle.” Typically, the muscles involved in myopathy are the muscles that control your voluntary movements.

The main symptom of myopathy is muscle weakness. However, other common symptoms include muscle spasms, stiffness, and cramps.

This article will further define what myopathy is, as well as discuss the symptoms, causes, and treatments.

What is myopathy?

Woman lying on a medical bed being examined by a doctor
Santi Nuñez/Stocksy United

Myopathy refers to diseases that affect muscle tissue.

Symptoms of diseases of the muscle include weakness, inflammation, spasms, and cramps.

Myopathy can develop as the result of inherited disorders, such as muscular dystrophies, or acquired conditions of the muscles, such as the common muscle cramp. Other causes of myopathy include immune disorders that cause inflammation and pain.

Numerous inherited myopathies exist. They are often associated with the following:

The signs and symptoms of myopathy will vary depending on its cause.

Treatment options for myopathy include medications, physical therapy, and surgery.

In rare cases, myopathy may be a sign of a serious neuromuscular disorder. Seek immediate medical care for serious symptoms Trusted Source PubMed Central Highly respected database from the National Institutes of Health Go to source , including:

  • severe weakness
  • quickly worsening weakness
  • trouble breathing

Symptoms of myopathy

Myopathy causes dysfunction of the muscles due to inflammation or disease. It can cause a number of symptoms. These symptoms can vary in intensity among individuals. They will also vary based on the cause and type of myopathy.

Shared symptoms of myopathy

There are some symptoms that are shared across myopathies. These include:

To learn more about when to see a doctor about fatigue, click here.

Contact your doctor if you experience any of these symptoms.

Types of myopathy

There are different types of myopathy. The varying types and specific conditions are grouped into the following categories:

  • Muscular: This type includes progressive weakness of the voluntary muscles and is sometimes evident at birth.
  • Mitochondrial: This type is caused by genetic abnormalities in the mitochondria, the structures in the cells that control energy. This includes Kearns-Sayre syndrome, myoclonic epilepsy with ragged red fibers, and mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes.
  • Congenital: This type of myopathy is evident by developmental delays in motor skills, as well as skeletal facial abnormalities often evident at birth. This type includes central core disease.
  • Glycogen storage diseases of muscle: These are due to mutations in the genes controlling the enzymes that metabolize blood sugar. These include Pompe disease, Andersen disease, and Cori disease.
  • Myoglobinuria: This type of myopathy is due to disorders in the metabolism of myoglobin, a fuel necessary for muscle activity. Diseases in this category include McArdle disease, Tarui disease, and Dimauro disease.
  • Myositis ossificans: In this condition, bone grows in muscle tissue.
  • Neuromyotonia: This features alternating episodes of twitching and stiffness.
  • Familial periodic paralysis: This features episodes of weakness in the arms and legs.
  • Stiff-person syndrome: This condition includes episodes of rigidity and reflex spasms.
  • Tetany: This features prolonged spasms of the arms and legs.

The common muscle cramp and stiffness in your muscles also count as myopathy.

For more information on muscle spasms, click here.


Dermatomyositis is an inflammatory condition of the skin and muscle. It causes a rash and, in some cases, cough, shortness of breath, or both.

Specific symptoms of dermatomyositis include:

  • weight loss
  • skin rash
  • low fever
  • calcium deposits under the skin
  • sensitivity to light

Polymyositis, inclusion body myositis, and others

These types are inflammatory myopathies that affect the skeletal muscles.

The specific symptoms include:

  • difficulty with day-to-day activities, such as buttoning a shirt
  • weakness in fingers, wrists, or both
  • difficulty lifting objects
  • difficulty reaching overhead
  • difficulty getting up from a seated position
  • conditions such as arthritis, congestive heart failure, or irregular heartbeat

Causes of myopathy

Myopathy refers to any disease or disorder that affects the muscles.

Diseases of the muscle can result in weakness, inflammation, spasms, and atrophy.

There are a few possible causes of myopathy, including:

  • genetics
  • metabolic disorders
  • endocrine disorders
  • muscle injuries
  • infections
  • medications
  • thyroid diseases
  • electrolyte levels

The causes of inflammatory myopathies are unknown.

Risk factors for myopathy

A number of factors increase the risk of developing myopathy. Not everyone with these risk factors will get myopathy.

Some myopathies, such as muscular dystrophy, are inherited.

Other risk factors for myopathy include:

Contact your doctor if you are concerned about any symptoms you have.

Diagnosis of myopathy

To diagnose myopathy, your doctor will first need to find the cause of it. This may include a referral to a specialist.

Your doctor will ask questions about your symptoms, family medical history, and personal medical history. They will then most likely order a series of tests.

These tests include:

Treatment of myopathy

Treatment options for myopathy depend on the specific type of condition or disease.

For some conditions, your doctor may only recommend supportive or symptomatic treatments, as these may be all that is needed or available.

Other possible treatments include:

  • medications
  • occupational therapy
  • physical therapy
  • advanced skin care
  • orthopedic and assistive devices

Certain myopathies, such as inflammatory types, can lead to permanent disability

when left untreated. Discuss any concerns you have with your doctor and follow the treatment plan they make for you.

Outlook for myopathy

For those diagnosed with myopathy, the prognosis can vary depending on the cause, type, and severity.

For many, this means a typical life span with little to no disability.

For those who are diagnosed with a progressive disorder, this may mean it becomes severely disabling, life threatening, or fatal.

Talk with your doctor about the outlook for your specific myopathy diagnosis.


The term “myopathy” refers to diseases and disorders that affect the muscles.

There are many different types and causes of myopathy. Common shared symptoms among these include muscle weakness and fatigue.

Treatment for myopathy generally includes medications and therapies.

Contact your doctor to discuss your symptoms, possible treatments, and the outlook for any myopathy condition you may have.

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Medical Reviewer: Meredith Goodwin, MD, FAAFP
Last Review Date: 2022 Mar 16
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