Muscle Diseases In Adults

  • 1st Revision: Anahit Navasardyan (Ann)
  • 2nd Revision: Kaamya MehtaLinkedin

Overview, Symptoms, Diagnosis and Treatment

Neuromuscular Disease (NMD) is a broad term that refers to a variety of disorders that affect muscle function, either directly through pathologies of the voluntary muscle or indirectly through pathologies of the peripheral nervous system or neuromuscular junctions. Other illnesses of the spinal cord or brain are not classified as "neuromuscular." NMD has an effect on the nerves that govern voluntary muscles. 

Voluntary muscles are muscles that can be controlled, such as the arms and legs. The messages that govern these muscles are sent by nerve cells, also known as neurons. Communication between the nervous system and muscles is disrupted when neurons become sick or die. Muscles weaken and fade away as a result. Twitching, cramps, aches and pains, as well as joint and movement issues, are all symptoms of weakness. It can also have an impact on cardiac function and breathing.

The following are some examples of NMD:

  • Motor Neuron Disease – amyotrophic lateral sclerosis,
  • Multiple sclerosis (MS),
  • Myasthenia gravis,
  • Atrophy of the spinal muscles.

Many NMDs are genetic, meaning they run in families or are caused by a gene mutation, as in muscle dystrophies. Myasthenia gravis is an example of an immune system disorder that can cause muscle dystrophy. Most muscular system illnesses are incurable. The good news is that they are frequently treatable and manageable. Symptom relief, illness progression delay, and improved quality of life are all possible treatment aims.

Drug therapy may be used as part of the treatment. Immunosuppressants, or medications that inhibit or prevent immune system overactivity, are one example. Some muscle and nerve illnesses may be treated with these medications. They can also be used to treat disorders that affect the nerves as well as the muscles. Muscle spasms and cramps may be treated with corticosteroids and other medicines.

Types of muscular dystrophy and neuromuscular diseases in adults

Myotonic Dystrophy

Age: 20-40 years

Myotonic dystrophy, often known as Steinert's disease, is a kind of muscular dystrophy that affects both men and women. The illness mostly affects the muscles of your face. The heart, thyroid, gastrointestinal tract, adrenal glands, and central nervous system are among the other body organs that may be damaged by Myotonic dystrophy. The illness progresses slowly, and the intensity of the symptoms varies from person to person.

Usually, the symptoms begin in the face and neck. The following are some of the most common symptoms of myotonic dystrophy:

  • Swallowing difficulties,
  • Vision problems,
  • Eyelids that droop,
  • Difficulty in lifting the neck,
  • Excessive sweating.

In women, myotonic dystrophy can cause irregular periods and infertility, while in men, it can cause impotence.

Facioscapulohumeral Muscular Dystrophy (FSHD)

Age: Teenage-early adulthood

Facioscapulohumeral muscular dystrophy (FSHD), also known as Landouzy-Dejerine disease, affects the face, shoulders, and hips. The illness progresses slowly but rapidly deteriorates. The illness can affect both men and women, and its severity can range from mild to extremely incapacitating.

The following are some of the symptoms of Facioscapulohumeral muscular dystrophy (FSHD):

  • Swallowing difficulties,
  • Chewing difficulty,
  • Changes in facial features,
  • Muscle weakness in the face,
  • Hearing issues or respiratory issues (rare)

Individuals with this illness, for the most part, have a normal lifespan. 

Oculopharyngeal Muscular Dystrophy (OPMD)

Age: 40-70 years 

The terms oculopharyngeal and pharyngeal apply to the eyes and the throat. Both men and women are susceptible to the illness, which mostly affects the muscles of the face, neck, and shoulders. Individuals with the illness may develop weakness in their pelvic and shoulder muscles as it advances. Individuals with a life expectancy of 50 to 60 years have a gradual course of the disease.

Oculopharyngeal muscular dystrophy symptoms include:

  • Swallowing difficulties
  • Walking difficulty
  • Eyelids that droop
  • Variations in the voice
  • Problems with vision
  • Heart and circulatory difficulties
  • Choking

Distal Muscular Dystrophy

Age: 40-60 years

Distal muscular dystrophy, also known as Distal Myopathy, is an uncommon disorder that affects your heart muscles and breathing system. The illness progresses slowly, eventually leading to total disability.

Distal muscular dystrophy symptoms include:

  • Walking difficulty,
  • Motor skills deterioration,
  • Muscle weakness in the shoulder, upper arm, and shin.

In comparison to other forms of the illness, the advancement is sluggish and only affects a few muscles. Aside from muscular dystrophies, the neuromuscular system is affected by three additional important illnesses. They are as follows:

Motor Neuron Diseases

It's an uncommon disorder that mostly affects the brain and nerves. Motor neurons are a sort of nerve cell that transmits messages around your body to allow you to move. The two primary types of motor neurons are upper motor neurons and lower motor neurons. When motor neurons die, it is difficult for muscles to receive electrical impulses from the brain, resulting in muscle atrophy. This illness involves a loss of control over motions; making walking, talking, breathing, and swallowing difficult.


Neuropathy, also known as peripheral neuropathy, is a condition in which one or more nerves are damaged, causing numbness, muscle weakness, and discomfort. The illness most usually affects the hands and feet, although it can also affect other regions of the body. Charcot-Marie-Tooth disease, diabetes, and chronic inflammatory demyelinating neuropathy are all disorders of the peripheral nerve (CIDP).

Neuromuscular Junction Disorders

The signal to contract a muscle is inhibited in neuromuscular junction disorders as it seeks to close the gap between the nerve and the muscle. The most prevalent of these diseases is myasthenia gravis, which is an inflammatory disease in which the immune system produces antibodies that attach to the neuromuscular junction and prevent nerve impulse transmission to the muscle.

What is the most common muscle disease in adults?

Myotonic dystrophy type 1 (DM1) is the most prevalent adult-onset muscular dystrophy, affecting roughly one in every 8,000 to 20,000 people in the general population. Myotonic dystrophy type 1 (DM1) and type 2 (DM2) prevalence vary substantially between countries and ethnic groups.

The overall prevalence and incidence of EDMD are unknown.  FSHD is the third most frequent kind of MD after dystrophinopathies and myotonic dystrophy, with an estimated frequency of 4 to 10 per 100,000.  The LGMDs are estimated to have a prevalence of 10 to 23 per 100,000. 7 MD affects around 250,000 persons in the United States.

What are the 7 most common diseases of the muscular system in adults?


Myositis is an inflammatory condition that affects muscles and the tissues that surround them, including blood vessels. Polymyositis (PM) is a very uncommon form of myositis. PM is more common in adults over the age of 20, especially women. Muscle inflammation and weakness are common symptoms of PM. A person with this syndrome may fall and have difficulty getting up after a fall. Other signs and symptoms include a chronic dry cough and/or swallowing difficulties.

There is no known cause for PM and it is uncurable. Fortunately, the problem is manageable.


Dermatomyositis (DM) is an inflammatory muscle condition that affects a small number of people. It can affect persons of any age or gender, though women are more likely to be affected. (4)

The following are some of the most common DM symptoms:

  • A rash that stands out,
  • Muscle deterioration,
  • Muscles that are inflamed and uncomfortable.

The cause, like that of other inflammatory myopathies, is unknown. There is no cure, however, medicines and other therapy can help manage the illness.

Myasthenia Gravis

Myasthenia gravis (MG) is a neuromuscular autoimmune disease. Problems with the way the nerves and muscles act together produce neuromuscular disorders. The immune system wrongly assaults the receptors that allow nerve cells and muscles to communicate in persons with MG. This causes muscle weakness by interfering with nerve signals to the muscles. The most frequent autoimmune neuromuscular condition is MG. It affects 20 persons out of every 100,000. The weakening of the voluntary skeletal muscles is the most common symptom of MG. Although there is no cure for MG, therapy can help to control the immune system's activity. The prognosis for MG varies from person to person. Some will only have minor symptoms. Others might become handicapped. Early intervention can help to reduce the severity of the condition.


Rhabdomyolysis is a condition that causes skeletal muscle breakdown. Myoglobin is released into the bloodstream as a result of this breakdown. Myoglobin is a protein that helps muscles store oxygen. Kidney injury can occur if there is too much myoglobin in the blood.

Rhabdomyolysis can be caused by a variety of factors, including medications for trauma, infection, and inflammation. Toxins are linked to a variety of genetic and metabolic problems.

The severity of the symptoms and the occurrence of complications determine the course of treatment.


Cardiomyopathy, often known as heart muscle disease, is a condition affecting the heart muscle. The heart becomes abnormally enlarged, thickened, and/or rigid in cardiomyopathy. This makes it more difficult for the heart muscle to efficiently pump blood. This could eventually lead to cardiac failure. Blood and other bodily fluids may back up into the lungs and other organs. Cardiomyopathy can also result in irregular heart rhythms and difficulties with the heart valves.


Sarcopenia, commonly known as geriatric muscular disease, is a prevalent ailment among the elderly. In elderly persons, other types of muscular illnesses are less common. Sarcopenia is a 14 per cent risk in older persons aged 65 to 70. Over the age of 80, this risk increases to 53%. Muscle mass and strength are lost because of sarcopenia. The following are some of the risk factors:

  • Nutritional deficiencies,
  • Chronic illness,
  • Hormone levels are lower.

Muscle weakness can strike anyone at any time. Others experience it gradually over many years.

What about neuromuscular disorders in children?

Neuromuscular disorders are caused by a faulty, duplicated, or absent gene in children and adults (a genetic disorder). The majority of neuromuscular diseases start at birth. Many people, however, go misdiagnosed for years, either because symptoms take time to show or because the disorders are so uncommon that diagnosing them can be difficult.

Carriers are people who pass on faulty genes to their children. Most carriers are unaware of the problem until their child is identified since they rarely experience the effects of the faulty gene. A child will not show symptoms of several illnesses unless both parents are carriers. In many circumstances, the same two parents may have children who are affected and children who are not. The child is frequently the first member of the family to develop the disease. It's unclear whether environmental variables play a role in the development of genetic defects. Neuromuscular problems, on the other hand, are rarely induced by accidents or injuries.

Summary and Conclusion

Muscle diseases can emerge on their own or because of other illnesses. Muscle diseases include ailments that induce muscle inflammation as well as neuromuscular problems.

Muscle diseases can cause muscle weakness, difficulty moving and balancing, as well as other symptoms such as numbness, droopy eyelids, and difficulty eating or breathing.

Muscle illnesses can be caused by a variety of factors, including heredity and autoimmune diseases. In certain cases, the cause is unknown.

A test that monitors electrical activity in the muscles is frequently used to diagnose muscle disorders. Although most of these conditions are incurable, many of them can be treated.


  1. Barhum, L. (2020). Muscular System Diseases and How They Affect Muscles. [online] Verywell Health. Available at:
  2. Royal College of Nursing (2021). Neuromuscular disorders | Neuroscience nursing | Royal College of Nursing. [online] The Royal College of Nursing. Available at:
  3. URMC (2020). Types of Muscular Dystrophy and Neuromuscular Diseases - Health Encyclopedia - University of Rochester Medical Center. [online] Available at:
  4. NHS Choices (2020). Types - Muscular dystrophy. [online] NHS. Available at:
This content is purely informational and isn’t medical guidance. It shouldn’t replace professional medical counsel. Always consult your physician regarding treatment risks and benefits. See our editorial standards for more details.

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Ankita Thakur

Postgraduate Degree, MSc. Biotechnology and Management, University of Glasgow
Experienced as a Healthcare Management Intern and Healthcare Writer.

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