Myopathy: Causes, Symptoms, Diagnosis, Treatment and Daily Support
Updated: 3 days ago
Medically reviewed by Dr. Baraa Alnahhal, MD · Last reviewed: October 2026
Quick Answer: What is myopathy?
Myopathy is a general term for diseases that affect skeletal muscle fibers and can make muscles weak. They may be inherited or acquired from other disorders, infections, medications or hormone problems. Common signs include weakness in the shoulders and hips, cramps and difficulty climbing stairs. Treatment depends on the type and may include therapy, exercise and medicines.
What the research says
Weakness is very common in critical illness, and muscle loss is fast. In a systematic review and meta-analysis of 52 studies (3,251 critically ill adults), in the studies that measured muscle size (1,773 patients), patients lost an average of 1.75% of rectus femoris thickness per day during the first week of ICU care (95% CI −2.05 to −1.45), and in the studies that assessed weakness (1,478 patients), the overall prevalence of ICU-acquired weakness was 48% (95% CI 39%–56%). ICU-acquired weakness is a broader category than critical illness myopathy (Fazzini et al., Crit Care, 2023). [1]
Medicines can affect muscle, but muscle symptoms on a medicine do not always mean the medicine is the cause. In a meta-analysis of 13 randomized trials (1,868 participants) in people with a history of statin-associated muscle symptoms, muscle symptoms were not more frequent with statin-based therapy than with comparators (OR 1.19, 95% CI 0.86–1.64), although stopping because of muscle symptoms was more frequent (OR 1.48, 95% CI 1.03–2.12). The authors concluded that rechallenge may be possible, which is a decision for the prescribing clinician (Aebi et al., PLoS One, 2025). [2]
Some drug-related muscle disease is rare but serious and can involve swallowing and speech. A systematic review and pooled analysis of 136 patients with immune checkpoint inhibitor-related myositis, myocarditis and myasthenia gravis overlap found 39.0% in-hospital mortality; older age and complete conduction block were associated with worse outcomes, and a symptom cluster of difficulty swallowing, slurred speech and neck weakness was described. The evidence came mainly from case reports and small series (Wei et al., Front Immunol, 2026). [3]
What is myopathy?
Myopathy describes diseases that affect skeletal muscles. Skeletal muscles are the muscles that connect to bones and help you move, maintain posture and perform everyday activities.
In myopathy, muscle fibers are affected and the muscles may become weak. The word does not identify one single illness. It is an umbrella term that includes many conditions with different causes, ages of onset, patterns and treatments.
Some myopathies are inherited. Others are acquired later in life. The distinction matters because it helps guide the evaluation and the treatment plan.
What are the two broad types of myopathy?
The two broad types of myopathy are inherited myopathy, caused by a genetic change, and acquired myopathy, which develops later and may relate to another disorder, medication or toxin.
Category | What it means | Examples described in this guide |
Inherited myopathy | A muscle disease present because of an inherited or other genetic change | Congenital, mitochondrial, metabolic myopathies and muscular dystrophies |
Acquired myopathy | A muscle disease that develops later and may relate to another disorder, infection, medication, toxin, hormone problem, electrolyte imbalance or critical illness | Autoimmune/inflammatory, toxic, endocrine, infectious, electrolyte-related and critical illness myopathies |
Inherited myopathies
Inherited myopathies are often linked to an abnormal gene mutation passed through a family, although some genetic conditions can occur without a known family history.
Congenital myopathies often begin at birth or in early childhood, but symptoms may not appear until the teen years or adulthood. Weakness commonly affects all muscles rather than only the muscles closest to the center of the body, and it is often not progressive.
Mitochondrial myopathies result from defects in mitochondria, the energy-producing parts of cells. They cause muscle weakness and may also affect other organ systems, including the heart, brain and gastrointestinal tract.
Metabolic myopathies result from gene defects affecting enzymes needed for normal muscle function. They may cause exercise intolerance, pain in the shoulders or thighs after exertion, non-traumatic rhabdomyolysis or episodes of weakness separated by periods of normal strength.
Muscular dystrophies involve progressive degeneration of muscle tissue because structural support proteins are abnormal or insufficient. They can affect the arms and legs to varying degrees, and some forms also involve the muscles of the eyes or face.
Acquired myopathies
Acquired myopathies develop later in life. They may result from an autoimmune or inflammatory disorder, a toxin or medication, a hormone disorder, an infection, an electrolyte imbalance or critical illness.
Autoimmune or inflammatory myopathies occur when the body attacks itself and interferes with muscle function.
Toxic myopathy occurs when a toxin or medication affects muscle structure or function. Examples discussed in clinical care include alcohol, toluene, some immunotherapy medicines, corticosteroids, statins, amiodarone, colchicine, chloroquine, some antivirals and protease inhibitors used for HIV, and omeprazole.
Endocrine myopathies occur when hormones interfere with muscle function. They can be associated with low or high thyroid activity, hyperparathyroidism, Addison’s disease or Cushing syndrome.
Infectious myopathies can follow viral, bacterial, parasitic or fungal infections. Examples include HIV, influenza, Epstein-Barr virus, bacterial pyomyositis, Lyme disease, trichinosis, toxoplasmosis, cysticercosis, Candida and coccidioidomycosis.
Electrolyte-related myopathy can occur when potassium or magnesium levels interfere with muscle function.
Critical illness myopathy affects limb muscles and the muscles that help with breathing. It develops during intensive care and may be related in part to prolonged immobility or medicines used during critical illness, including muscle relaxants, corticosteroids or sedatives.
What are the common symptoms of myopathy?
Many myopathies share a pattern of muscle weakness that is similar on both sides of the body. Weakness is often most noticeable in proximal muscles, the muscles closest to the center of the body.
Symptom or pattern | How it may affect daily life |
Weakness in shoulders and upper arms | Difficulty reaching overhead, combing hair or changing a ceiling light bulb |
Weakness in hips and thighs | Trouble standing from a chair, climbing stairs or walking with usual endurance |
Symmetric weakness | Similar weakness on both sides of the body |
Muscle cramps, stiffness or spasms | Painful or uncomfortable muscle activity during rest or movement |
Fatigue with exertion | Muscles tire during activity more quickly than expected |
Lack of energy | Reduced ability to sustain routine tasks |
Shortness of breath with exertion | Breathing may feel difficult during activity, depending on the muscles involved |
Swallowing or speech difficulty | Problems with muscles that control swallowing or speech may cause choking or slurred words |
The hands and feet are not usually the main areas affected. Symptoms vary depending on the specific type of myopathy.
Weakness may be non-progressive, very slowly progressive or intermittent. Some disorders cause episodes of weakness with periods of normal strength between episodes.
Myopathy in children
Children may show slower development of motor skills such as walking, hopping, climbing stairs or grasping a spoon or pencil. A child may also struggle to keep up with peers during sports or games.
A child’s abilities should be considered in context, without assuming that every difference in strength or endurance represents myopathy. A qualified healthcare professional can evaluate persistent or concerning patterns.
Who can develop myopathy?
Anyone can develop a myopathy, but certain factors may increase the likelihood of particular forms.
Factor | Why it may matter |
Family history | May increase the chance of inheriting an abnormal gene associated with muscle disease |
Sex-linked inheritance | Some myopathies are carried on the X chromosome and affect more males, while other inherited forms affect people of all sexes |
Autoimmune, metabolic or endocrine disorder | May increase the likelihood of an acquired myopathy |
Medication or toxin exposure | Some medicines and toxins can interfere with muscle structure or function |
Intensive-care stay | Prolonged immobility and medicines used during critical illness may contribute to critical illness myopathy |
How common myopathy is depends on the type. Some inherited forms are rare, while muscular dystrophies are among the more common inherited myopathies.
When should you talk with a healthcare professional about myopathy?
Start with a primary care clinician if you are concerned about ongoing muscle weakness, unusual fatigue with exertion, repeated cramps or difficulty with everyday tasks. Depending on the symptoms, you may be referred to a neurologist or rheumatologist.
Arrange an evaluation if weakness is persistent, affects both sides of the body, interferes with bathing or dressing, makes it difficult to stand or climb stairs, or is accompanied by swallowing, speech or breathing-muscle concerns.
If breathing or swallowing changes are sudden, severe or rapidly worsening, seek prompt medical care. Do not assume that a new breathing or swallowing problem is simply a matter of being out of shape.
How is myopathy diagnosed?
Diagnosis begins with a detailed review of symptoms and history. A healthcare professional may ask about when weakness began, whether it changes over time, family history, prescription medicines, possible toxin exposure and other medical conditions.
The physical examination may assess the skin, reflexes, muscle strength, balance and sensation.
Tests that may be used
Test or evaluation | What it can contribute |
Blood tests | May measure muscle enzymes such as creatine kinase or aldolase, electrolytes, autoimmune markers, inflammation markers and thyroid hormones |
Electromyography and nerve-conduction studies | Assess electrical conduction in nerves and the type and degree of muscle damage |
Muscle MRI | Provides images of muscle tissue |
Genetic testing | Looks for gene changes associated with inherited myopathy |
Muscle biopsy | Removes a small piece of muscle tissue for testing |
Not everyone needs every test. The evaluation is selected according to the symptoms, examination and suspected type of myopathy.
Preparing for an appointment
Bring a list of prescription and nonprescription medicines, supplements and recent changes. Write down when weakness began, which activities are difficult, whether symptoms are symmetric, and whether cramps, stiffness, spasms, swallowing or speech changes occur.
If relatives have had unexplained muscle weakness or a diagnosed muscle disorder, mention that history. A short activity and symptom record may also help describe patterns that come and go.
How is myopathy treated?
Treatment is tailored to the specific myopathy and the person’s symptoms. Many plans include physical therapy, occupational therapy and some form of exercise.
Supportive therapy and exercise
Physical therapy can help address movement and function. Occupational therapy can help with everyday activities and practical adaptations. Exercise may be part of care, but the appropriate intensity and type depend on the myopathy.
Discuss an exercise plan with a clinician before starting, especially if you are considering weight lifting or if activity causes marked weakness, pain or fatigue.
Treatment for inflammatory or autoimmune myopathy
The goal is to reduce inflammation and the body’s autoimmune response. Treatment may include immunomodulatory or immunosuppressant medicines, immunoglobulin given intravenously or under the skin, and corticosteroids.
Treatment for inherited or genetic myopathy
Many inherited or genetic myopathies do not currently have a specific treatment or cure. Management may focus on symptoms and therapy. Some conditions, including Duchenne muscular dystrophy and Pompe disease, have specific medicines. Research and clinical trials continue in several areas, including gene therapy.
Treatment for other acquired myopathies
Treatment may focus on the underlying disorder. Endocrine myopathies are managed by addressing the hormone condition. Toxic myopathy may improve when the offending toxin or medication is stopped under clinical guidance. Infectious myopathy is treated by addressing the infection, which may include antibiotics for bacterial causes.
Do not stop a prescribed medicine without speaking with the clinician who prescribed it. A medication change should be planned safely.
How can people live well with myopathy?
Myopathy may be a long-term condition, whether inherited or acquired. Daily support focuses on preserving function, following the treatment plan and noticing changes early.
Area of daily support | General direction |
Nutrition | Eat a balanced diet with a variety of fruits and vegetables |
Activity | Stay active with mild cardiovascular exercise when appropriate; discuss weight lifting and other demanding exercise first |
Weight | Work toward a healthy weight with individualized guidance |
Skin protection | If a dermatomyositis rash is present, protect skin from sunlight with covering and sunscreen with SPF 30 or higher |
Swallowing | If swallowing is difficult, ask about soft or semisolid foods and safer eating strategies |
Positioning | If bedbound, eat sitting up in bed as directed by a qualified professional |
Therapies | Participate in physical, occupational or speech therapy when recommended |
Medicines | Take medications as prescribed and discuss concerns before making changes |
Follow-up | Track changes in symptoms and attend scheduled visits so the plan can be adjusted |
Adapting everyday tasks
Simple tasks such as bathing, dressing, grooming, standing from a chair or reaching overhead may become difficult when proximal muscles are weak. Occupational therapy can help identify practical ways to conserve energy, change the setup of a task or use an assistive strategy.
Ask for help when a task feels unsafe. Needing support with an activity is not a personal failure; it is information that can help the care team adapt the plan.
Swallowing, speech and breathing muscles
Some myopathies affect the muscles involved in swallowing and speech, which can lead to choking or slurred words. Critical illness myopathy can affect the muscles that help with breathing. Report these changes to a qualified healthcare professional so they can be assessed.
What questions should you ask about myopathy at an appointment?
Useful questions about myopathy include which muscles are involved, whether a medication or other factor may contribute, whether it is inherited and which tests and exercises are appropriate.
What pattern of weakness do you see, and which muscles are involved?
Could a medication, toxin, infection, hormone problem or electrolyte imbalance be contributing?
Does my family history suggest an inherited form?
Which tests are most useful for my symptoms?
Should I see a neurologist, rheumatologist, therapist or another specialist?
Which forms of exercise are appropriate, and which should I avoid?
What changes in swallowing, speech, breathing or strength should prompt earlier follow-up?
What practical changes could make bathing, dressing, stairs or reaching safer?
Conclusion
Myopathy is a broad term for diseases that affect skeletal muscles. It can be inherited or acquired, and the symptoms and treatment depend on the specific form. Symmetric weakness in the shoulders, upper arms, hips or thighs, along with cramps, fatigue or difficulty with everyday activities, deserves a thoughtful clinical evaluation.
Diagnosis may involve history, examination, blood tests, EMG, MRI, genetic testing or muscle biopsy. Treatment may include physical and occupational therapy, carefully selected exercise, medicines for inflammatory disease, treatment of infection or hormone disorders, medication review and practical daily support.
If weakness is persistent, worsening or interfering with daily life, start a conversation with a qualified healthcare professional. Changes involving swallowing, speech or breathing muscles deserve prompt attention.
Frequently Asked Questions
Is myopathy one disease?
No. Myopathy is a general term for diseases that affect skeletal muscles. It includes inherited and acquired conditions with different causes, patterns and treatments.
What is the most common symptom of myopathy?
Many myopathies cause symmetric muscle weakness, especially in the shoulders, upper arms, hips and thighs. Cramps, stiffness, spasms, fatigue with exertion and low energy can also occur.
Can myopathy cause trouble climbing stairs?
Yes. Weakness in the hips and thighs can make climbing stairs, standing from a chair or reaching overhead more difficult.
Can myopathy affect swallowing or speech?
Some myopathies affect the muscles that control swallowing and speech. This can lead to choking or slurred words and should be discussed with a healthcare professional.
Can myopathy affect breathing?
Some myopathies involve the respiratory muscles. Critical illness myopathy can affect the muscles used for breathing, and shortness of breath with exertion can occur in some myopathies.
Are myopathies inherited?
Some are. Inherited forms can be related to abnormal gene changes and include congenital, mitochondrial, metabolic myopathies and muscular dystrophies. Other myopathies develop later in life and are acquired.
What tests are used to diagnose myopathy?
Possible tests include blood tests, EMG and nerve-conduction studies, muscle MRI, genetic tests and muscle biopsy. The exact evaluation depends on symptoms and examination findings.
Is there a treatment for myopathy?
Treatment depends on the specific type. Physical therapy, occupational therapy and appropriate exercise are common parts of care. Other treatments may include immunosuppressive medicines, corticosteroids, immunoglobulin, specific medicines for some inherited conditions, or treatment of an infection, hormone disorder, toxin or medication cause.
Should I exercise if I have muscle weakness?
Exercise may be part of treatment, but the type and intensity should be individualized. Discuss an exercise routine with a qualified healthcare professional before starting, especially weight lifting or activity that causes marked symptoms.
What should I do if I suspect myopathy?
Start by contacting a primary care clinician. Depending on the symptoms, you may be referred to a neurologist, rheumatologist or another specialist. Bring information about symptoms, family history, medicines and possible exposures.
Related Reading
Learn more in our guide to Creatine Kinase (CK) Test: What It Is, Normal Levels and High CK Causes.
References
Fazzini B, Märkl T, Costas C, et al. The rate and assessment of muscle wasting during critical illness: a systematic review and meta-analysis. Crit Care. 2023;27(1):2. PMID 36597123. https://doi.org/10.1186/s13054-022-04253-0
Aebi PS, Villoz F, Bührer J, et al. Safety outcomes of statin vs non-statin lipid-lowering interventions in patients with prior statin-associated muscle symptoms: a systematic review and meta-analysis. PLoS One. 2025;20(12):e0338575. PMID 41379822. https://doi.org/10.1371/journal.pone.0338575
Wei M, Hu T, Yang L, et al. Immune checkpoint inhibitor-related myositis, myocarditis, and myasthenia gravis overlap syndrome: a systematic review and pooled analysis of individual cases. Front Immunol. 2026;17:1854723. PMID 42591394. https://doi.org/10.3389/fimmu.2026.1854723
Disclaimer
This article is for general educational purposes and is not a substitute for professional medical advice, diagnosis or treatment. Always seek the advice of a qualified healthcare professional with any questions about a medical condition or treatment.
Persistent weakness, or any change in swallowing, speech or breathing, needs professional evaluation. Do not stop a prescribed medicine or start an exercise program for muscle weakness without guidance from a qualified clinician.
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