In medicine

Medicine

Medicine is the science and art of healing. It encompasses a variety of health care practices evolved to maintain and restore health by the prevention and treatment of illness....

, a myopathy is a muscular disease

Disease

A disease is an abnormal condition affecting the body of an organism. It is often construed to be a medical condition associated with specific symptoms and signs. It may be caused by external factors, such as infectious disease, or it may be caused by internal dysfunctions, such as autoimmune...

 in which the muscle fibers do not function for any one of many reasons, resulting in muscular weakness. "Myopathy" simply means muscle disease (myo- Greek

Greek language

Greek is an independent branch of the Indo-European family of languages. Native to the southern Balkans, it has the longest documented history of any Indo-European language, spanning 34 centuries of written records. Its writing system has been the Greek alphabet for the majority of its history;...

 μυο "muscle" + pathos -pathy

Pathos

Pathos represents an appeal to the audience's emotions. Pathos is a communication technique used most often in rhetoric , and in literature, film and other narrative art....

 Greek

Greek language

Greek is an independent branch of the Indo-European family of languages. Native to the southern Balkans, it has the longest documented history of any Indo-European language, spanning 34 centuries of written records. Its writing system has been the Greek alphabet for the majority of its history;...

 "suffering"). This meaning implies that the primary defect is within the muscle, as opposed to the nerves ("neuropathies" or "neurogenic" disorders) or elsewhere (e.g., the brain etc.). Muscle cramps, stiffness

Stiffness

Stiffness is the resistance of an elastic body to deformation by an applied force along a given degree of freedom when a set of loading points and boundary conditions are prescribed on the elastic body.-Calculations:...

, and spasm

Spasm

In medicine a spasm is a sudden, involuntary contraction of a muscle, a group of muscles, or a hollow organ, or a similarly sudden contraction of an orifice. It is sometimes accompanied by a sudden burst of pain, but is usually harmless and ceases after a few minutes...

 can also be associated with myopathy.

Muscular disease can be classified as neuromuscular

Neuromuscular disease

Neuromuscular disease is a very broad term that encompasses many diseases and ailments that either directly, via intrinsic muscle pathology, or indirectly, via nerve pathology, impair the functioning of the muscles....

 or musculoskeletal

Musculoskeletal disorders

Musculoskeletal disorders can affect the body's muscles, joints, tendons, ligaments and nerves. Most work-related MSDs develop over time and are caused either by the work itself or by the employees' working environment...

 in nature. Some conditions, such as myositis

Myositis

Myositis is a general term for inflammation of the muscles. Many such conditions are considered likely to be caused by autoimmune conditions, rather than directly due to infection It is also a documented side effect of the lipid-lowering drugs statins and fibrates.Elevation of creatine kinase in...

, can be considered both neuromuscular and musculoskeletal.

Classes

There are many types of myopathy. ICD-10

ICD

The International Statistical Classification of Diseases and Related Health Problems is a medical classification that provides codes to classify diseases and a wide variety of signs, symptoms, abnormal findings, complaints, social circumstances, and external causes of injury or disease...

 codes are provided here where available.

Inherited Forms

• (G71.0) Dystrophies (or muscular dystrophies) are a subgroup of myopathies characterized by muscle degeneration and regeneration. Clinically, muscular dystrophies are typically progressive, because the muscles' ability to regenerate is eventually lost, leading to progressive weakness, often leading to use of a wheelchair
  Wheelchair
  A wheelchair is a chair with wheels, designed to be a replacement for walking. The device comes in variations where it is propelled by motors or by the seated occupant turning the rear wheels by hand. Often there are handles behind the seat for someone else to do the pushing...
  
  , and eventually death, usually related to respiratory weakness.
• (G71.1) Myotonia
  Myotonia
  Myotonia is a symptom of a small handful of certain neuromuscular disorders characterized by the slow relaxation of the muscles after voluntary contraction or electrical stimulation. Generally, repeated effort is needed to relax the muscles, and the condition improves after the muscles have warmed...
  
  
  • Neuromyotonia
    Neuromyotonia
    Neuromyotonia , also known as Isaacs' syndrome, is a form of peripheral nerve hyperexcitability that causes spontaneous muscular activity resulting from repetitive motor unit action potentials of peripheral origin.-Causes:...
    
    
• (G71.2) The congenital myopathies
  Congenital myopathy
  Congenital myopathy is a term for any muscle disorder present at birth. By this definition the congenital myopathies could include hundreds of distinct neuromuscular syndromes and disorders...
  
   do not show evidence for either a progressive dystrophic process (i.e., muscle death) or inflammation, but instead characteristic microscopic changes are seen in association with reduced contractile ability of the muscles. Congenital myopathies include, but are not limited to:
  • (G71.2) nemaline myopathy
    Nemaline myopathy
    Nemaline myopathy is a congenital, hereditary neuromuscular disorder that causes muscle weakness, generally nonprogressive, of varying severity....
    
     (characterized by presence of "nemaline rods" in the muscle),
  • (G71.2) multi/minicore myopathy (characterized by multiple small "cores" or areas of disruption in the muscle fibers),
  • (G71.2) centronuclear myopathy (or myotubular myopathy) (in which the nuclei
    Cell nucleus
    In cell biology, the nucleus is a membrane-enclosed organelle found in eukaryotic cells. It contains most of the cell's genetic material, organized as multiple long linear DNA molecules in complex with a large variety of proteins, such as histones, to form chromosomes. The genes within these...
    
     are abnormally found in the center of the muscle fibers), a rare muscle wasting
    Wasting
    In medicine, wasting refers to the process by which a debilitating disease causes muscle and fat tissue to "waste" away. Wasting is sometimes referred to as "acute malnutrition" because it is believed that episodes of wasting have a short duration, in contrast to stunting, which is regarded as...
    
     disorder
• (G71.3) Mitochondrial myopathies, which are due to defects in mitochondria, which provide a critical source of energy for muscle
• (G72.3) Familial periodic paralysis
• (G72.4) Inflammatory myopathies
  Inflammatory myopathy
  Inflammatory myopathy is a form of myopathy that involves inflammation of the muscle.Inflammatory myopathy is generally synonymous to the term dermatopolymyositis, which, according to ICD-10 encompasses three related diseases: polymyositis, dermatomyositis, and inclusion-body...
  
  , which are caused by problems with the immune system attacking components of the muscle, leading to signs of inflammation
  Inflammation
  Inflammation is part of the complex biological response of vascular tissues to harmful stimuli, such as pathogens, damaged cells, or irritants. Inflammation is a protective attempt by the organism to remove the injurious stimuli and to initiate the healing process...
  
   in the muscle
• (G73.6) Metabolic myopathies
  Metabolic myopathy
  Metabolic myopathies are Myopathies that result from defects in biochemical metabolism that primarily affect muscle. They include:1- Glycogen storage diseases2- Lipid storage disorder3- Phosphocreatine stores disorder- External links :* - eMedicine...
  
  , which result from defects in biochemical metabolism that primarily affect muscle
  • (G73.6/E74.0) Glycogen storage disease
    Glycogen storage disease
    Glycogen storage disease is the result of defects in the processing of glycogen synthesis or breakdown within muscles, liver, and other cell types. GSD has two classes of cause: genetic and acquired. Genetic GSD is caused by any inborn error of metabolism involved in these processes...
    
    s, which may affect muscle
  • (G73.6/E75) Lipid storage disorder
    Lipid storage disorder
    Lipid storage disorders are a group of inherited metabolic disorders in which harmful amounts of lipids accumulate in some of the body’s cells and tissues. People with these disorders either do not produce enough of one of the enzymes needed to metabolize lipids or they produce enzymes that do...
    
    

Acquired

• (G72.0 - G72.2) External substance induced myopathy
  • (G72.0) Drug-induced myopathy
    • Glucocorticoid
      Glucocorticoid
      Glucocorticoids are a class of steroid hormones that bind to the glucocorticoid receptor , which is present in almost every vertebrate animal cell...
      
       myopathy is caused by this class of steroids increasing the breakdown
      Catabolism
      Catabolism is the set of metabolic pathways that break down molecules into smaller units and release energy. In catabolism, large molecules such as polysaccharides, lipids, nucleic acids and proteins are broken down into smaller units such as monosaccharides, fatty acids, nucleotides, and amino...
      
       of the muscle proteins leading to muscle atrophy
      Muscle atrophy
      Muscle atrophy, or disuse atrophy, is defined as a decrease in the mass of the muscle; it can be a partial or complete wasting away of muscle. When a muscle atrophies, this leads to muscle weakness, since the ability to exert force is related to mass...
      
      .
  • (G72.1) Alcoholic myopathy
  • (G72.2) Myopathy due to other toxic agents
• (M33.0-M33.1)
  • Dermatomyositis
    Dermatomyositis
    Dermatomyositis is a connective-tissue disease related to polymyositis and Bramaticosis that is characterized by inflammation of the muscles and the skin.- Causes :...
    
     produces muscle weakness and skin changes. The skin rash is reddish and most commonly occurs on the face, especially around the eyes, and over the knuckles and elbows. Ragged nail folds with visible capillaries can be present. It can often be treated by drugs like corticosteroids or immunosuppressants. (M33.2)
  • Polymyositis
    Polymyositis
    Polymyositis is a type of chronic inflammation of the muscles related to dermatomyositis and inclusion body myositis.-Signs and symptoms:...
    
     produces muscle weaknesss. It can often be treated by drugs like corticosteroids or immunosuppressants.
  • Inclusion body myositis
    Inclusion body myositis
    Inclusion body myositis is an inflammatory muscle disease, characterized by slowly progressive weakness and wasting of both distal and proximal muscles, most apparent in the muscles of the arms and legs...
    
     is a slowly progressive disease that produces weakness of hand grip and straightening of the knees. No effective treatment is known.
• (M61) Myositis ossificans
  Myositis ossificans
  Myositis ossificans comprises two syndromes characterized by heterotopic ossification of muscle.-Classification:* In the first, and by far most common type, nonhereditary myositis ossificans , calcifications occur at the site of injured muscle, most commonly in the arms or...
  
  
• (M62.89) Rhabdomyolysis
  Rhabdomyolysis
  Rhabdomyolysis is a condition in which damaged skeletal muscle tissue breaks down rapidly. Breakdown products of damaged muscle cells are released into the bloodstream; some of these, such as the protein myoglobin, are harmful to the kidneys and may lead to kidney failure...
  
   and (R82.1) myoglobinuria
  Myoglobinuria
  Myoglobinuria is the presence of myoglobin in the urine, usually associated with rhabdomyolysis or muscle destruction. Myoglobin is present in muscle cells as a reserve of oxygen.-Causes:...
  
  s

Symptoms

• Common muscle weakness. Also (R25.2) cramps (M25.6) stiffness
  Stiffness
  Stiffness is the resistance of an elastic body to deformation by an applied force along a given degree of freedom when a set of loading points and boundary conditions are prescribed on the elastic body.-Calculations:...
  
  , and (R29.0) tetany
  Tetany (medical sign)
  Tetany is a medical sign consisting of the involuntary contraction of muscles, which may be caused by disease or other conditions that increase the action potential frequency...
  
  

Treatments

Because different types of myopathies are caused by many different pathways, there is no single treatment for myopathy. Treatments range from treatment of the symptoms to very specific cause-targeting treatments. Drug therapy, physical therapy

Physical therapy

Physical therapy , often abbreviated PT, is a health care profession. Physical therapy is concerned with identifying and maximizing quality of life and movement potential within the spheres of promotion, prevention, diagnosis, treatment/intervention,and rehabilitation...

, bracing for support, surgery

Surgery

Surgery is an ancient medical specialty that uses operative manual and instrumental techniques on a patient to investigate and/or treat a pathological condition such as disease or injury, or to help improve bodily function or appearance.An act of performing surgery may be called a surgical...

, massage, and even acupuncture

Acupuncture

Acupuncture is a type of alternative medicine that treats patients by insertion and manipulation of solid, generally thin needles in the body....

are all current treatments for a variety of myopathies.

External links

• GeneReviews/NCBI/NIH/UW entry on Myopathy with Deficiency of ISCU
• See http://neuromuscular.wustl.edu/ for medical descriptions.