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]

Overview

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

• Aconitase deficiency 
• Addison's disease
• Adenosine monophosphate deaminase deficiency
• Alcoholism
• Aldolase a deficiency 
• Alpha-mannosidase deficiency
• Amish nemaline myopathy
• Amyloidosis
• Anoctaminopathy
• Arnold stickler bourne syndrome 
• Arthrogryposis
• Atorvastatin
• Barth syndrome
• Becker muscular dystrophy
• Bethlem myopathy
• Bezafibrate
• Borud syndrome 
• Brody myopathy
• Brown recluse spider poisoning 
• Calpainopathy
• Carey-fineman-ziter syndrome
• Carnitine deficiency
• Carnitine palmitoyltransferase 2 deficiency
• Caveolin-3 related distal myopathy
• Chanarin-dorfman disease
• Chloroquine
• Christian syndrome 1
• Chronic hypokalemia
• Clevudine
• Colchicine
• Congenital muscular dystrophy
• Cushing's disease
• Cytochrome-c oxidase deficiency
• Dermatomyositis
• Desmin-related myopathy
• Diabetes
• Distal myopathy 2
• Duchenne muscular dystrophy
• Efavirenz
• Emery-dreifuss muscular dystrophy
• Ethanol
• Familial partial lipodystrophy type 2
• Forbes disease
• 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
• Hiv-1 disease
• Hypercalcemia
• Hyperkalemia
• Hypermagnesemia
• Hyperparathyroidism
• Hyperthyroidism
• Hypocalcaemia
• Hypokalaemia
• Hyponatremia
• Hypothyroidism
• Kearns-sayre syndrome 
• Lactate dehydrogenase deficiency
• Laing distal myopathy
• Lama2-related muscular dystrophy
• Limb girdle muscular dystrophy
• Long chain hydroxyacyl-coa dehydrogenase deficiency
• Lundberg ii syndrome 
• Malignancy
• Malignant hyperthermia
• Marinesco-sjogren-garland syndrome
• Melas 
• Merrf
• Mitochondrial myopathy
• Mitochondrial trifunctional protein deficiency
• Miyoshi muscular dystrophy 2
• Molybdenum cofactor deficiency
• Muscle-eye-brain disease
• Muscular dystrophy
• Myoneurogastrointestinal encephalopathy syndrome
• Myosin storage myopathy
• Myotonia congenita
• Myotonic dystrophy
• Neutral lipid storage disease
• Niacin
• Nonaka myopathy
• Osteomalacia
• Periodic paralysis
• Phencyclidine 
• Phosphogylcerate mutase 2 deficiency
• Plasma membrane carnitine transporter deficiency
• Polymyositis
• Polyneuropathy
• Pork tapeworm 
• Pravastatin
• Prednisolone
• Progressive external ophthalmoplegia
• Proximal renal tubular acidosis
• Rickets
• Rigid spine muscular dystrophy
• Rippling muscle disease
• Rosuvastatin
• Salih myopathy
• Sarcoidosis
• Short chain acyl-coa dehydrogenase deficiency
• Simvastatin
• Spheroid body myopathy 
• Steroids
• Stormorken syndrome
• Subacute necrotising encephalomyelopathy
• Tel hashomer camptodactyly syndrome
• Telbivudine
• Thyroid eye disease 
• Tk2-related mitochondrial dna depletion syndrome
• Triosephosphate isomerase deficiency
• Tubular aggregate myopathy
• Type iii glycogen storage disease 
• Udd-markesbery tardive muscular dystrophy
• Ullrich congenital muscular dystrophy
• Walker-warburg syndrome
• Welander muscular dystrophy
• Wieacker-wolff syndrome
• Woods black norbury syndrome
• Xanthine oxidase deficiency
• Zidovudine

Differential Diagnosis of Muscle Weakness

To review the differential diagnosis of Proximal muscle weakness, click here.

To review the differential diagnosis of Distal muscle weakness, click here.

To review the differential diagnosis of inflammatory myopathy, click here.

To review the differential diagnosis of Muscle weakness and Fever, click here.

To review the differential diagnosis of Muscle weakness and Myalgia, click here.

To review the differential diagnosis of Muscle weakness and Gait abnormality, click here.

To review the differential diagnosis of Muscle weakness and Neuropathy, click here.

To review the differential diagnosis of Muscle weakness and stiffness, click here.

To review the differential diagnosis of Muscle weakness and Myoglobinuria, click here.

To review the differential diagnosis of Muscle weakness and Atrophy, click here.

Organ system	Disease	Symptoms												History	Physical Examination	Diagnosis
		Age of onset	Muscle weakness	Fever	Myalgia	Contractures	Gait abnormality	Neuropathy	Atrophy	Stiffness	Myoglobinuria	Other features	Laboratory Findings			Creatine Kinase	Muscle Biopsy	Electromyogram
Medication−induced	Corticosteroids	Variable	Proximal	−	+	−	−	−	+	−	−	Central obesity Excessive sweating Insomnia Reduced libido  Amenorrhea Infertility  Psychological disturbances	Positive h/o medications	Facial and sphincter muscles are usually spared	Positive ACTH stimulation test 24-hour urine cortisol Low dose dexamethasone suppression test	Normal	Normal	Normal
	Statins	60+	Proximal	−	+	−	−	−	−	−	−/+(Rhabdomyolysis)	N/A	Positive h/o medications H/o other medication use	Tenderness Muscle aches	↑↑ Liver enzymes	↑↑	Necrosis Degeneration, and regeneration of fibers Phagocytic infiltration	Normal
	Alcohol	Variable	Proximal	−	−	−	+	+/−	−	−	−	Swelling Tender Erythema and induration	Alcohol intoxication	Change in mental status Telangiectasia Peripheral neuropathy	Monspecific and are normal in many patients	Normal or ↑↑	Normal	Normal
Organ system	Disease	Age of onset	Muscle weakness	Fever	Myalgia	Contractures	Gait abnormality	Neuropathy	Atrophy	Stiffness	Myoglobinuria	Other features	History	Physical Examination	Laboratory Findings	Creatine Kinase	Muscle Biopsy	Electromyogram
Endocrine	Cushing's disease	25 −45	Proximal	−	−	−	−	−	+	−	−	Decreased libido Obesity/weight gain Plethora Round face Menstrual changes Hirsutism Hypertension Ecchymoses Lethargy Depression Dorsal fat pad Abnormal glucose tolerance	N/A	Facial and sphincter muscles are usually spared Overweight Straie Moon face HTN Hyperpigmentation	Positive ACTH stimulation test 24-hour urine cortisol Low dose dexamethasone suppression test	Normal	Atrophy of type 2 muscle fibers, especially type 2B	Normal
	Adrenal insufficiency	30−50 years	Proximal	−	+	−	−	−	−	+	−	Signs of glucocorticoid, mineralocorticoid, and, androgen deficiency	Signs of postural hypotension History of tuberculosis History of malignancy History of other autoimmune disease	Hypotension  Hyperpigmentation  Auricular−cartilage calcification  Vitiligo	Electrolyte abnormalities Hypoglycemia	Normal	Normal	Normal
	Hyperaldosteronism with myopathy	50	Proximal & distal	−	−	−	−	−	−	−	+ Rhabdomyolysis	Palpitations Hypertension	Episodes of increased heart beats	Hyperpigmentation	Hypokalemia	Normal	Normal	Normal
	Hyperthyroidism	40	Proximal	−	−	−	−	−	+	+	+	Signs of hyperthyroidism	H/o of weight loss	Sweating Tremor Neck swelling	Decreased TSH	↑↑	Non specific	Myotonic
	Hypothyroidism	55	Proximal	−	+	+	−	−	+	+	+ Rhabdomyolysis	Signs of hypothyroidism	H/o weight gain	Myxoedema  Muscle pseudohypertrophy	Increased TSH	↑↑	Nonspecific	Normal
	Diabetic infraction	45	Proximal	+	+	−	−	+	+	−	−	Cramps Sudden onset of pain Anterior thigh muscles are most commonly involved	H/O long standing diabetes	Swelling Tenderness	Elevated ESR Leukocytosis	Normal	Necrosis Edema	Normal
Organ system	Disease	Age of onset	Muscle weakness	Fever	Myalgia	Contractures	Gait abnormality	Neuropathy	Atrophy	Stiffness	Myoglobinuria	Other features	History	Physical Examination	Laboratory Findings	Creatine Kinase	Muscle Biopsy	Electromyogram
Inflammatory/ Rheumatologic	Dermatomyositis	40s−50s Can affect children	Proximal	+	+	−	−	−	−	+	−	Rash Dyspnea Weight loss Cough	Viral infections Cancer	Heliotrope rash on face and hands Telangiectasia Erythema Mechanic's hands Gottron's sign ( violaceous scaly eruption )	↑↑ ESR ↑↑ CRP	↑↑	Perimysial mononuclear infiltrate	Myopathic
	Polymyositis	> 18 years	Proximal	+	+	−	−	−	−	+	−	Similar to dermatomyositis without mucous and skin involvement	N/A	N/A	↑↑ ESR ↑↑ CRP	↑↑	Endomysial mononuclear infiltrate Patchy necrosis
	Inclusion body myositis	50s	Proximal & distal	−	−	−	−	−	−	−	−	Dysphagia Asymmetric weakness	Retrovirus (most common)	N/A	Antibodies to cytoplasmic 5'−nucleotidase	↑↑	Inflammatory cells Invading muscle cells Vacuolar degeneration Inclusions or plaques	Neurogenic
	Fibromyalgia	40−50s	Generalized	−	−	−	−	+	−	−	−	Anxiety or depression features Fatigue Sleep disturbance Numbness Muscle spasms	History of depression	Tenderness in the soft tissue anatomical location	Normal	Normal	Normal	Normal
	Polymyalgia Rheumatica	50s	Diffuse	+	+	−	−	−	−	+	−	Weight loss	History of joints stiffness, worse in the morning	Restricted shoulder motion	↑↑ ESR ↑↑ CRP	Normal	Normal	Normal
Organ system	Disease	Age of onset	Muscle weakness	Fever	Myalgia	Contractures	Gait abnormality	Neuropathy	Atrophy	Stiffness	Myoglobinuria	Other features	History	Physical Examination	Laboratory Findings	Creatine Kinase	Muscle Biopsy	Electromyogram
Genetic	Becker muscular dystrophy	<13yrs	Proximal	−	−	+	+	−	+	−	−	Milder form of Duchenne	Growth delay Age of onset of symptoms is much delayed than duchenne	Positive Grower sign	Decreased amount of dystrophin.	↑↑	Muscle fibril degeneration, regeneration Isolated fiber hypertrophy Muscle replacement with fat and connective tissue	Myopathic
	Duchenne muscular dystrophy	<13 yrs	Proximal	−	−	+	+	−	+	−	−	Calf psedohypertrophy Cardiomyopathy Kyphoscoliosis Cognitive impairment	Early onset	Positive Grower sign	Errors in the Xp21 gene. Absence of dystrophin.	↑↑
	Limb−girdle muscular dystrophies	<15 yrs	Proximal	−	+	+	+	−	+	−	−	Calf hypertrophy Scapular winging Cardiomyopathy Cardiac arrhythmias Respiratory muscle weakness	Autosomal dominant Deterioration of ability to run/walk	Muscle weakness is generally symmetric	LMNA gene CAV3 gene	↑↑	N/A	Myopathic
	Myotonic dystrophy	<18 years	Proximal & distal	−	−	+	+	−	−	+	−	Myotonia Cataracts Diabetes mellitus Frontal balding Cardiac arrhythmias Cholecystitis Pregnancy Eyelid ptosis	Positive family history	Muscles often contract and are unable to relax	Mutations in the DMPK gene	N/A	N/A	Myopathic
	Glycogen storage disease	Variable	Proximal	−	−	−	−	−	+	−	−	AR Faituge Hypoglycemia	Exercise intolerance	Hypotonia Hepatomegaly	Lactic acidosis Elevated liver enzymes Ketosis	↑↑	Normal	Normal
Organ system	Disease	Age of onset	Muscle weakness	Fever	Myalgia	Contractures	Gait abnormality	Neuropathy	Atrophy	Stiffness	Myoglobinuria	Other features	History	Physical Examination	Laboratory Findings	Creatine Kinase	Muscle Biopsy	Electromyogram
Infectious	Lyme disease	Variable	Proximal	+	+	−	+/−	+	−	−	−	Erythema Migrans Flu−like symptoms Lyme arthritis Neurological manifestations	H/o tick bite Hiking trip	Target−like lesions HSM	Clinical diagnosis +Serology	N/A	N/A	N/A
	Influenza	Variable	Proximal and Distal	+	+	−	+	−	−	−	+	Fever Malaise Rhinorrhea Muscle pain worse with movement	Cold weather H/o Ill contacts	Muscle weakness, tenderness, and swelling.	↑↑ Liver enzymes Positive PCR	↑↑	N/A	N/A
	Polio	<5 yrs	Proximal	−	−	−	+	+	+	−	−	Asymmetrical paralysis Muscle atrophy Tremors Skeletal deformities	History of skipped immunization.	Normal Meningeal signs Asymmetrical flaccid paralysis Pharyngeal paralysis	Isolation from pharyngealsecretions, CSF Positive serology	N/A	N/A	Neurological pattern
	Syphilis	Variable	Negative	−	−	−	+	+	−	−	−	Chancre Lymphadenopathy Condylomata lata Neuro syphilis Cardiovascular syphilis	History of risk factors (MSM, unprotected sex, multiple sex partners)	Non−tender chancre in primary syphilis. Followed by rash Generalized lymphadenopathy in secondary syphilis	Darkfield examinations VDRL RPR FTA−ABS	N/A	N/A	N/A
	Pyomyositis	Variable	Proximal & Distal	+	+	−	−	−	−	+	−	Fever Malaise Psoas abscess	Immunocompromised	Muscles are painful, swollen, tender, and indurated. Depending on the site of involvement, it may mimic appendicitis (psoas muscle), septic arthritis of the hip (iliacus muscle), or epidural abscess (piriformis muscle).	Leukocytosis Elevated ESR	N/A	N/A	N/A
Organ system	Disease	Age of onset	Muscle weakness	Fever	Myalgia	Contractures	Gait abnormality	Neuropathy	Atrophy	Stiffness	Myoglobinuria	Other features	History	Physical Examination	Laboratory Findings	Creatine Kinase	Muscle Biopsy	Electromyogram
Neurologic	ALS	>35	Proximal & Distal Distal	−	−	−	−	+	+	+	−	Dysphagia Spasticity Hyperreflexia Babinski's +	N/A	Both upper and lower motor neuron signs	Clinical diagnosis	Normal	Nonspecific findings of chronic denervation with reinnervation	Neuropathic
	Stroke	>65	Proximal & distal	−	−	−	+	+	+	−	−	Dysphagia Unilateral/Bilateral weakness	H/o HTN, dyslipidaemia DM	Weakness of the involved arm	Head CT	Normal	Normal	Neuropathic
	GBS	18 −350	Proximal	−	−	−	+	−	−	+	−	Ascending paralysis	Precedes a gastrointestinal disease	Weakness of lower extremities followed by upper extremities	Cytologic albumin ratio	Normal	Normal	Neuropathic
	Multiple Sclerosis	30's	Proximal & distal	−	−	−	+	+	−	−	−	Ocular findings Urinary incontinence Problems with speech or swallowing	Attacks or exacerbation	Localized weakness Focal sensory disturbances Hyper reactive reflexes Increased tone or stiffness	Head CT ologo−clonal bands	Normal	N/A	Neuropathic
Organ system	Disease	Age of onset	Muscle weakness	Fever	Myalgia	Contractures	Gait abnormality	Neuropathy	Atrophy	Stiffness	Myoglobinuria	Other features	History	Physical Examination	Laboratory Findings	Creatine Kinase	Muscle Biopsy	Electromyogram
Neuromuscular	Botulinum	Variable	Distal	−	−	−	+	−	−	+	−	Double vision Blurred vision Drooping eyelids Slurred speech Difficulty swallowing	H/O food exposure	Hyporeflexia Decreased strength	+Toxin	Normal	N/A	Myopathic
	Lambert−Eaton syndrome	Variable	Distal	−	−	+	+	−	−	+	−	Weakness of the bulbar muscles Ocular Limb weakness	Weaknessa is often relieved temporarily after exertion or physical exercise.		Antibodies against voltage−gated calcium channels
	Myasthenia gravis	Variable	Proximal	−	−	+	+	−	−	+	−	Ocular Bulbar  Limb weakness Isolated neck, limbs and respiratory weakness	Weakness often worsens with activity		Antibodies that block or destroy nicotinic acetylcholine receptors

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.