Myopathy

Myopathy
Myopathy: Metabolic {Acid maltase) Image courtesy of Professor Peter Anderson DVM PhD and published with permission © PEIR, University of Alabama at Birmingham, Department of Pathology
ICD-10	G71 - G72
ICD-9	359.4 - 359.9
DiseasesDB	8723
eMedicine	emerg/328
MeSH	D009135

Template:Search infobox Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]

Please Take Over This Page and Apply to be Editor-In-Chief for this topic: There can be one or more than one Editor-In-Chief. You may also apply to be an Associate Editor-In-Chief of one of the subtopics below. Please mail us [2] to indicate your interest in serving either as an Editor-In-Chief of the entire topic or as an Associate Editor-In-Chief for a subtopic. Please be sure to attach your CV and or biographical sketch.

In medicine, a myopathy is a neuromuscular disease 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 μυσ "muscle" + pathy Greek "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, and spasm can also be associated with myopathy.

Classes

Because myopathy is such a general term, there are several classes of myopathy.... (ICD-10 codes are provided where available.)

• (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, and eventually death, usually related to respiratory weakness.
• (G71.1) Myotonia
  • Neuromyotonia
• (G71.2) The congenital myopathies 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. Among others, different congenital myopathies include:
  • (G71.2) nemaline myopathy (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 are abnormally found in the center of the muscle fibers) is a rare muscle wasting disorder that occurs in three forms:
    • The most severe form is present at birth, which is inherited as an X-linked genetic trait, and can cause severe respiratory muscle weakness. This is the form of centronuclear myopathy currently referred to as myotubular myopathy.
    • A less severe form of centronuclear myopathy that may present itself at birth or in early childhood progresses slowly and is inherited as an autosomal recessive genetic trait.
    • The least severe of the three forms of centronuclear myopathy first appears during the second and third decades of life and is slowly progressive; it is inherited as an autosomal dominant genetic trait.
• (G71.3) Mitochondrial myopathies are due to defects in mitochondria, which provide a critical source of energy for muscle.
• (G72.3) Familial periodic paralysis
• (G72.4) Inflammatory myopathies are caused by problems with the immune system attacking components of the muscle, leading to signs of inflammation in the muscle.
• (G73.6) Metabolic myopathies result from defects in biochemical metabolism that primarily affect muscle
  • (G73.6/E74.0) Glycogen storage diseases may affect muscle
  • (G73.6/E75) Lipid storage disorder
• (M33.0-M33.1) Dermatomyositis, (M33.2) polymyositis, inclusion body myositis, and related myopathies
• (M61) Myositis ossificans
• (M62.89) Rhabdomyolysis and (R82.1) myoglobinurias
• Common muscle (R25.2) cramps and (M25.6) stiffness, and (R29.0) tetany

Causes

Life Threatening Causes

• Amyloidosis
• Malignancy
• Osteomalacia
• Polymyositis
• Sarcoidosis

Common Causes

• Aconitase deficiency 
• Becker muscular dystrophy
• Brody myopathy
• Caveolin-3 related distal myopathy
• Congenital muscular dystrophy
• Desmin-related myopathy
• Distal myopathy 2
• Duchenne muscular dystrophy
• Emery-dreifuss muscular dystrophy
• Familial partial lipodystrophy type 2
• Laing distal myopathy
• Lama2-related muscular dystrophy
• Limb girdle muscular dystrophy
• Mitochondrial myopathy
• Mitochondrial trifunctional protein deficiency
• Miyoshi muscular dystrophy 2
• Muscular dystrophy
• Myoneurogastrointestinal encephalopathy syndrome
• Myosin storage myopathy
• Myotonia congenita
• Myotonic dystrophy
• Nonaka myopathy
• Osteomalacia
• Polymyositis
• Rigid spine muscular dystrophy
• Rippling muscle disease
• Salih myopathy
• Spheroid body myopathy 
• Tubular aggregate myopathy
• Ullrich congenital muscular dystrophy
• Welander muscular dystrophy

Causes by Organ System

Cardiovascular	Bezafibrate, Neutral lipid storage disease
Chemical/Poisoning	Brown recluse spider poisoning
Dental	No underlying causes
Dermatologic	Dermatomyositis, Malignant hyperthermia
Drug Side Effect	Atorvastatin, Chloroquine, Clevudine, Colchicine, Efavirenz, Ethanol, Niacin, Phencyclidine , Pravastatin, Prednisolone, Rosuvastatin, Simvastatin, Steroids, Telbivudine, Zidovudine
Ear Nose Throat	No underlying causes
Endocrine	Addison's disease, Amyloidosis, Carnitine deficiency, Cushing's disease, Forbes disease, Hyperparathyroidism, Hyperthyroidism, Hypothyroidism, Thyroid eye disease , Type iii glycogen storage disease
Environmental	Malignant hyperthermia
Gastroenterologic	Forbes disease, Glycogen branching deficiency , Glycogen storage diseases, Glycogenosis
Genetic	Aconitase deficiency , Aldolase a deficiency , Alpha-mannosidase deficiency, Amish nemaline myopathy, Anoctaminopathy, Arthrogryposis , Barth syndrome, Bethlem myopathy, Calpainopathy, Carey-fineman-ziter syndrome, Carnitine palmitoyltransferase 2 deficiency, Chanarin-dorfman disease, Christian syndrome 1, Cytochrome-c oxidase deficiency, Freeman-sheldon syndrome , Fukuyama congenital muscular dystrophy, Gigantism , Glutaric acidemia type 2, Glycerol kinase deficiency, Glycogen branching deficiency , Glycogen storage diseases, Glycogenosis , Hereditary fibrosing poikiloderma , Kearns-sayre syndrome , Lactate dehydrogenase deficiency, Marinesco-sjogren-garland syndrome, Melas , Merrf, Mitochondrial myopathy, Mitochondrial trifunctional protein deficiency, Miyoshi muscular dystrophy 2, Molybdenum cofactor deficiency, Myoneurogastrointestinal encephalopathy syndrome, Myosin storage myopathy, Myotonia congenita, Myotonic dystrophy, Periodic paralysis, Phosphogylcerate mutase 2 deficiency, Plasma membrane carnitine transporter deficiency, Short chain acyl-coa dehydrogenase deficiency, Stormorken syndrome, Subacute necrotising encephalomyelopathy, Tel hashomer camptodactyly syndrome, Tk2-related mitochondrial dna depletion syndrome, Triosephosphate isomerase deficiency, Udd-markesbery tardive muscular dystrophy, Walker-warburg syndrome, Welander muscular dystrophy, Wieacker-wolff syndrome, Woods black norbury syndrome, Xanthine oxidase deficiency
Hematologic	Chronic hypokalemia, Diabetes, Hypercalcemia, Hyperkalemia, Hypermagnesemia, Hypocalcaemia, Hypokalaemia, Hyponatremia, Long chain hydroxyacyl-coa dehydrogenase deficiency
Iatrogenic	No underlying causes
Infectious Disease	Hiv-1 disease, Pork tapeworm
Musculoskeletal/Orthopedic	Aconitase deficiency , Becker muscular dystrophy, Brody myopathy, Caveolin-3 related distal myopathy, Congenital muscular dystrophy, Desmin-related myopathy, Distal myopathy 2, Duchenne muscular dystrophy, Emery-dreifuss muscular dystrophy, Familial partial lipodystrophy type 2, Laing distal myopathy, Lama2-related muscular dystrophy, Limb girdle muscular dystrophy, Mitochondrial myopathy, Mitochondrial trifunctional protein deficiency, Miyoshi muscular dystrophy 2, Muscular dystrophy, Myoneurogastrointestinal encephalopathy syndrome, Myosin storage myopathy, Myotonia congenita, Myotonic dystrophy, Nonaka myopathy, Osteomalacia, Polymyositis, Rigid spine muscular dystrophy, Rippling muscle disease , Salih myopathy, Spheroid body myopathy , Tubular aggregate myopathy, Ullrich congenital muscular dystrophy, Welander muscular dystrophy
Neurologic	Arnold stickler bourne syndrome , Becker muscular dystrophy, Borud syndrome , Lundberg ii syndrome , Muscle-eye-brain disease, Polyneuropathy , Salih myopathy
Nutritional/Metabolic	Adenosine monophosphate deaminase deficiency, Chronic hypokalemia, Diabetes, Hypercalcemia, Hyperkalemia, Hypermagnesemia, Hypocalcaemia, Rickets
Obstetric/Gynecologic	No underlying causes
Oncologic	Malignancy
Ophthalmologic	Muscle-eye-brain disease, Progressive external ophthalmoplegia, Thyroid eye disease
Overdose/Toxicity	Alcoholism
Psychiatric	No underlying causes
Pulmonary	Sarcoidosis
Renal/Electrolyte	Hypokalaemia, Hyponatremia, Proximal renal tubular acidosis
Rheumatology/Immunology/Allergy	Amyloidosis, Dermatomyositis, Polymyositis, Sarcoidosis
Sexual	Hiv-1 disease
Trauma	No underlying causes
Urologic	No underlying causes
Miscellaneous	No underlying causes

Causes in Alphabetical Order

The unnamed parameter 2= is no longer supported. Please see the documentation for {{columns-list}}.

3

Treatment

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, bracing for support, surgery, and even acupuncture are current treatments for a variety of myopathies.

Prognosis

The prognosis for individuals with a myopathy varies. Some individuals have a normal life span and little or no disability. For others, however, the disorder may be progressive, severely disabling, life-threatening, or fatal.

Template:PNS diseases of the nervous system Template:SIB