Muscular dystrophy
https://https://www.youtube.com/watch?v=DGOmN6rnsNk%7C350}} |
Muscular Dystrophy | |
ICD-10 | G71.0 |
---|---|
ICD-9 | 359.0-359.1 |
MedlinePlus | 001190 |
MeSH | D009136 |
For patient information click here
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [2]; Associate Editor(s)-in-Chief: Kalsang Dolma, M.B.B.S.[3]
Overview
Muscular dystrophy refers to a group of genetic, hereditary muscle diseases that cause progressive muscle weakness.[1][2] Muscular dystrophies are characterized by progressive skeletal muscle weakness, defects in muscle proteins, and the death of muscle cells and tissue.[3] Nine diseases including Duchenne, Becker, limb girdle, congenital, facioscapulohumeral, myotonic, oculopharyngeal, distal, and Emery-Dreifuss are always classified as muscular dystrophy[4] but there are more than 100 diseases in total with similarities to muscular dystrophy. Most types of MD are multi-system disorders with manifestations in body systems including the heart, gastrointestinal and nervous systems, endocrine glands, skin, eyes and other organs.[4]
Historical Perspective
In the 1860s, descriptions of boys who grew progressively weaker, lost the ability to walk, and died at an early age became more prominent in medical journals. In the following decade, French neurologist Guillaume Duchenne gave a comprehensive account of thirteen boys with the most common and severe form of the disease, which now carries his name—Duchenne muscular dystrophy.
It soon became evident that the disease had more than one form.[4]
Classification
Type | OMIM | Gene | Description |
---|---|---|---|
Becker's muscular dystrophy | 300376 | DMD |
|
Congenital muscular dystrophy | Multiple | Multiple |
|
Duchenne muscular dystrophy | 310200 | DMD |
|
Distal muscular dystrophy | 254130 | DYSF |
|
Emery-Dreifuss muscular dystrophy | 310300, 181350 | EMD, LMNA |
|
Facioscapulohumeral muscular dystrophy | 158900 | DUX4 |
|
Limb-girdle muscular dystrophy | Multiple | Multiple |
|
Myotonic muscular dystrophy | 160900, 602668 | DMPK, ZNF9 |
|
Oculopharyngeal muscular dystrophy | 164300 | PABPN1 |
Pathophysiology
Genetic
These conditions are inherited, and the different muscular dystrophies follow various inheritance patterns
The best-known type, Duchenne muscular dystrophy (DMD), is inherited in an X-linked recessive pattern, meaning that the mutated gene that causes the disorder is located on the X chromosome, one of the two sex chromosomes, and is thus considered sex-linked. In males (who have only one X chromosome) one altered copy of the gene in each cell is sufficient to cause the condition. In females (who have two X chromosomes) a mutation must generally be present in both copies of the gene to cause the disorder (relatively rare exceptions, manifesting carriers, do occur due to dosage compensation/X-inactivation). Males are therefore affected by X-linked recessive disorders much more often than females. A characteristic of X-linked inheritance is that fathers cannot pass X-linked traits to their sons. In about two thirds of DMD cases, an affected male inherits the mutation from a mother who carries one altered copy of the DMD gene. The other one third of cases probably result from new mutations in the gene. Females who carry one copy of a DMD mutation may have some signs and symptoms related to the condition (such as muscle weakness and cramping), but these are typically milder than the signs and symptoms seen in affected males. Duchenne muscular dystrophy and Becker's muscular dystrophy are caused by mutations of the gene for the dystrophin protein and lead to an overabundance of the enzyme creatine kinase.[13][14] The dystrophin gene is the second largest gene in mammals.[15]
Differential Diagnosis
Muscular dystrophy must be differentiated from other diseases that cause muscle weakness, hypotonia, or paralysis:[16][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31]
Diseases | History and Physical | Diagnostic tests | Other Findings | ||||||||
---|---|---|---|---|---|---|---|---|---|---|---|
Motor Deficit | Sensory deficit | Cranial nerve Involvement | Autonomic dysfunction | Proximal/Distal/Generalized | Ascending/Descending/Systemic | Unilateral (UL)
or Bilateral (BL) or No Lateralization (NL) |
Onset | Lab or Imaging Findings | Specific test | ||
Adult Botulism | + | - | + | + | Generalized | Descending | BL | Sudden | Toxin test | Blood, Wound, or Stool culture | Diplopia, Hyporeflexia, Hypotonia, possible respiratory paralysis |
Infant Botulism | + | - | + | + | Generalized | Descending | BL | Sudden | Toxin test | Blood, Wound, or Stool culture | Flaccid paralysis (Floppy baby syndrome), possible respiratory paralysis |
Guillian-Barre syndrome[32] | + | - | - | - | Generalized | Ascending | BL | Insidious | CSF: ↑Protein
↓Cells |
Clinical & Lumbar Puncture | Progressive ascending paralysis following infection, possible respiratory paralysis |
Eaton Lambert syndrome[33] | + | - | + | + | Generalized | Systemic | BL | Intermittent | EMG, repetitive nerve stimulation test (RNS) | Voltage gated calcium channel (VGCC) antibody | Diplopia, ptosis, improves with movement (as the day progresses) |
Myasthenia gravis[34] | + | - | + | + | Generalized | Systemic | BL | Intermittent | EMG, Edrophonium test | Ach receptor antibody | Diplopia, ptosis, worsening with movement (as the day progresses) |
Electrolyte disturbance[35] | + | + | - | - | Generalized | Systemic | BL | Insidious | Electrolyte panel | ↓Ca++, ↓Mg++, ↓K+ | Possible arrhythmia |
Organophosphate toxicity[36] | + | + | - | + | Generalized | Ascending | BL | Sudden | Clinical diagnosis: physical exam & history | Clinical suspicion confirmed with RBC AchE activity | History of exposure to insecticide or living in farming environment. with : Diarrhea, Urination, Miosis, Bradycardia, Lacrimation, Emesis, Salivation, Sweating |
Tick paralysis (Dermacentor tick)[37] | + | - | - | - | Generalized | Ascending | BL | Insidious | Clinical diagnosis: physical exam & history | - | History of outdoor activity in Northeastern United States. The tick is often still latched to the patient at presentation (often in head and neck area) |
Tetrodotoxin poisoning[38] | + | - | + | + | Generalized | Systemic | BL | Sudden | Clinical diagnosis: physical exam & dietary history | - | History of consumption of puffer fish species. |
Stroke[39] | +/- | +/- | +/- | +/- | Generalized | Systemic | UL | Sudden | MRI +ve for ischemia or hemorrhage | MRI | Sudden unilateral motor and sensory deficit in a patient with a history of atherosclerotic risk factors (diabetes, hypertension, smoking) or atrial fibrillation. |
Poliomyelitis[40] | + | + | + | +/- | Proximal > Distal | Systemic | BL or UL | Sudden | PCR of CSF | Asymmetric paralysis following a flu-like syndrome. | |
Transverse myelitis[41] | + | + | + | + | Proximal > Distal | Systemic | BL or UL | Sudden | MRI & Lumbar puncture | MRI | History of chronic viral or autoimmune disease (e.g. HIV) |
Neurosyphilis[42][31] | + | + | - | +/- | Generalized | Systemic | BL | Insidious | MRI & Lumbar puncture | CSF VDRL-specifc | History of unprotected sex or multiple sexual partners.
History of genital ulcer (chancre), diffuse maculopapular rash. |
Muscular dystrophy[44] | + | - | - | - | Proximal > Distal | Systemic | BL | Insidious | Genetic testing | Muscle biopsy | Progressive proximal lower limb weakness with calf pseudohypertrophy in early childhood. Gower sign positive. |
Multiple sclerosis exacerbation[45] | + | + | + | + | Generalized | Systemic | NL | Sudden | ↑CSF IgG levels
(monoclonal) |
Clinical assessment and MRI [46] | Blurry vision, urinary incontinence, fatigue |
Amyotrophic lateral sclerosis[47] | + | - | - | - | Generalized | Systemic | BL | Insidious | Normal LP (to rule out DDx) | MRI & LP | Patient initially presents with upper motor neuron deficit (spasticity) followed by lower motor neuron deficit (flaccidity). |
Inflammatory myopathy[48] | + | - | - | - | Proximal > Distal | Systemic | UL or BL | Insidious | Elevated CK & Aldolase | Muscle biopsy | Progressive proximal muscle weakness in 3rd to 5th decade of life. With or without skin manifestations. |
Natural History, Complications and Prognosis
Prognosis
- The severity of disability depends on the type of muscular dystrophy. All types of muscular dystrophy slowly get worse, but how fast this happens varies widely.
- Some types of muscular dystrophy, such as Duchenne muscular dystrophy, are deadly. Other types cause little disability and people with them have a normal lifespan.
Complications
- Cardiomyopathy with heart failure
- Cataracts
- Decreased ability to care for self
- Decreased movement
- Depression
- Respiratory failure
- Contractures
- Mental impairment (varies)
- Scoliosis
Diagnosis
Symptoms
Principal symptoms include:
- Mental retardation (only present in some types of the condition)
- Muscle weakness that slowly gets worse
- Delayed development of muscle motor skills
- Difficulty using one or more muscle groups
- Drooling
- Eyelid drooping (ptosis)
- Frequent falls
- Loss of strength in a muscle or group of muscles as an adult
- Loss in muscle size(muscle atrophy)
- Problems walking (delayed walking)
Physical Examination
Heart
Arrythmia may be present.
Extremities
- Loss of muscle mass (wasting)
- Hypotonia
- Scoliosis
- Joint contractures (club foot, claw hand and others)
- Calf pseudohypertrophy
Laboratory Findings
Creatine Phosphokinase
Early in the disease process, creatine phosphokinase (CPK) levels are 50-300 times greater than normal levels, but the levels tend to decrease as the muscle mass decreases.
Electrocardiography
May show right ventricular strain pattern.
Electromyography
Myopathic disease has these defining EMG characteristics:
- A decrease in duration of the action potential
- A reduction in the area to amplitude ratio of the action potential
- A decrease in the number of motor units in the muscle (in extremely severe cases only)
Muscle Biopsy
- The diagnosis of muscular dystrophy is based on the results of a muscle biopsy. In some cases, a DNA blood test may be all that is needed.
- The optimal site for biopsy is the vastus lateralis muscle.
Treatment
- There is no known cure for muscular dystrophy. Inactivity (such as bed-rest and even sitting for long periods) can worsen the disease.
- Physical therapy and orthopedic instruments (e.g., wheelchairs, standing frames) may be helpful.
- Physical therapy to prevent contractures (a condition when an individual with a muscular dystrophy grows and the muscles don't move with the bones and can easily be slowed down and/or make the individual's body straighter by daily physical therapy), orthoses (orthopedic appliances used for support) and corrective orthopedic surgery may be needed to improve the quality of life in some cases.
- The cardiac problems that occur with Emery-Dreifuss muscular dystrophy and myotonic muscular dystrophy may require a pacemaker.
- The myotonia (delayed relaxation of a muscle after a strong contraction) occurring in myotonic muscular dystrophy may be treated with medications such as quinine, phenytoin, or mexiletine.
Research Projects
A grid computing-based research project called "Help Cure Muscular Dystrophy" was launched on December 19, 2006 by Décrypthon (a collaboration between French Muscular Dystrophy Association, French National Center for Scientific Research and IBM).
The Jain Foundation is involved in research into Miyoshi myopathy, a form of distal muscular dystrophy and LGMD2B, a limb-girdle muscular dystrophy.[49]
MY0-029
MYO-029 is an experimental myostatin inhibiting drug developed by Wyeth Pharmaceuticals for the treatment of muscular dystrophy. Myostatin is a protein that inhibits the growth of muscle tissue, MYO-029 is a recombinant human antibody designed to bind and inhibit the activity of myostatin. A 2005/2006 trial was completed by Wyeth in Collegeville, PA. As of April 2007, the results of the study have not yet been made public, but it is one of the few known drugs in development for the treatment for muscular dystrophy.
National research and support in the United States
Within the United States, the three primary federally funded organizations that focus on Muscular Dystrophy include the National Institute of Neurological Disorders and Stroke (NINDS), National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS), and National Institute of Child Health and Human Development (NICHD).[4]
In 1966, the Muscular Dystrophy Association began its annual Jerry Lewis MDA Telethon, which has arguably done more to raise awareness of muscular dystrophy than any other event or initiative.
On December 18, 2001 the MD CARE Act was signed into law and amends the Public Health Service Act to provide research for the various muscular dystrophies. This law also established the Muscular Dystrophy Coordinating Committee to help focus research efforts through a coherent research strategy.[50][51]
References
- ↑ Harrison's Principle's of Internal Medicine. 2005. p. 2527. doi:10.1036/0071402357. Unknown parameter
|coauthors=
ignored (help) - ↑ Muscular Dystrophy Campaign Retrieved 9 April 2007.
- ↑ Emery AE (2002). "The muscular dystrophies". Lancet. 359 (9307): 687–695. PMID 11879882.
- ↑ 4.00 4.01 4.02 4.03 4.04 4.05 4.06 4.07 4.08 4.09 4.10 4.11 May 2006 report to Congress on Implementation of the MD CARE Act, as submitted by Department of Health and Human Service's National Institutes of Health
- ↑ 5.0 5.1 [1]: MD USA Website (accessed 03SEP2007)
- ↑ "Congenital Muscular Dystrophy (CMD)". MDA. Retrieved 27 April 2012.
- ↑ 7.0 7.1 http://www.nlm.nih.gov/medlineplus/ency/article/000705.htm
- ↑ Emedicine re EDMD Retrieved 30 July 2007.
- ↑ Kolata, Gina (19 August 2010). "Reanimated 'Junk' DNA Is Found to Cause Disease". New York Times. Retrieved 29 August 2010.
- ↑ Lemmers, Richard (19 August 2010). "A Unifying Genetic Model for Facioscapulohumeral Muscular Dystrophy". Science. 329 (5999): 1650–3. doi:10.1126/science.1189044. PMID 20724583. Unknown parameter
|coauthors=
ignored (help) - ↑ Jenkins, Simon P.R. (2005). Sports Science Handbook:I - Z. Brentwood, Essex: Multi-Science Publ. Co. p. 121. ISBN 0906522-37-4.
- ↑ Turner, C (2010). "The myotonic dystrophies: diagnosis and management". J Neurol Neurosurg Psychiatry. 81: 358–367. doi:10.1136/jnnp.2008.158261. PMID 20176601. Unknown parameter
|coauthors=
ignored (help) - ↑ Medline Plus Medical Encyclopedia Retrieved 8 May 2007.
- ↑ Centres for Disease Control and Prevention Retrieved 8 May 2007.
- ↑ Living with Cerebral Palsy Retrieved 8 May 2007.
- ↑ 16.0 16.1 Kira R (February 2018). "[Acute Flaccid Myelitis]". Brain Nerve (in Japanese). 70 (2): 99–112. doi:10.11477/mf.1416200962. PMID 29433111.
- ↑ Hopkins SE (November 2017). "Acute Flaccid Myelitis: Etiologic Challenges, Diagnostic and Management Considerations". Curr Treat Options Neurol. 19 (12): 48. doi:10.1007/s11940-017-0480-3. PMID 29181601.
- ↑ Messacar K, Schreiner TL, Van Haren K, Yang M, Glaser CA, Tyler KL, Dominguez SR (September 2016). "Acute flaccid myelitis: A clinical review of US cases 2012-2015". Ann. Neurol. 80 (3): 326–38. doi:10.1002/ana.24730. PMC 5098271. PMID 27422805.
- ↑ Chong PF, Kira R, Mori H, Okumura A, Torisu H, Yasumoto S, Shimizu H, Fujimoto T, Hanaoka N, Kusunoki S, Takahashi T, Oishi K, Tanaka-Taya K (February 2018). "Clinical Features of Acute Flaccid Myelitis Temporally Associated With an Enterovirus D68 Outbreak: Results of a Nationwide Survey of Acute Flaccid Paralysis in Japan, August-December 2015". Clin. Infect. Dis. 66 (5): 653–664. doi:10.1093/cid/cix860. PMC 5850449. PMID 29028962.
- ↑ Messacar K, Asturias EJ, Hixon AM, Van Leer-Buter C, Niesters H, Tyler KL, Abzug MJ, Dominguez SR (August 2018). "Enterovirus D68 and acute flaccid myelitis-evaluating the evidence for causality". Lancet Infect Dis. 18 (8): e239–e247. doi:10.1016/S1473-3099(18)30094-X. PMID 29482893. Vancouver style error: initials (help)
- ↑ Chen IJ, Hu SC, Hung KL, Lo CW (September 2018). "Acute flaccid myelitis associated with enterovirus D68 infection: A case report". Medicine (Baltimore). 97 (36): e11831. doi:10.1097/MD.0000000000011831. PMC 6133480. PMID 30200066.
- ↑ "Botulism | Botulism | CDC".
- ↑ McCroskey LM, Hatheway CL (May 1988). "Laboratory findings in four cases of adult botulism suggest colonization of the intestinal tract". J. Clin. Microbiol. 26 (5): 1052–4. PMC 266519. PMID 3290234.
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- ↑ Dimachkie MM, Barohn RJ (May 2013). "Guillain-Barré syndrome and variants". Neurol Clin. 31 (2): 491–510. doi:10.1016/j.ncl.2013.01.005. PMC 3939842. PMID 23642721.
- ↑ Walling AD, Dickson G (February 2013). "Guillain-Barré syndrome". Am Fam Physician. 87 (3): 191–7. PMID 23418763.
- ↑ Gilhus NE (2011). "Lambert-eaton myasthenic syndrome; pathogenesis, diagnosis, and therapy". Autoimmune Dis. 2011: 973808. doi:10.4061/2011/973808. PMC 3182560. PMID 21969911.
- ↑ Krishnan C, Kaplin AI, Deshpande DM, Pardo CA, Kerr DA (May 2004). "Transverse Myelitis: pathogenesis, diagnosis and treatment". Front. Biosci. 9: 1483–99. PMID 14977560.
- ↑ Amato AA, Greenberg SA (December 2013). "Inflammatory myopathies". Continuum (Minneap Minn). 19 (6 Muscle Disease): 1615–33. doi:10.1212/01.CON.0000440662.26427.bd. PMID 24305450.
- ↑ 31.0 31.1 Berger JR, Dean D (2014). "Neurosyphilis". Handb Clin Neurol. 121: 1461–72. doi:10.1016/B978-0-7020-4088-7.00098-5. PMID 24365430.
- ↑ Talukder RK, Sutradhar SR, Rahman KM, Uddin MJ, Akhter H (2011). "Guillian-Barre syndrome". Mymensingh Med J. 20 (4): 748–56. PMID 22081202.
- ↑ Merino-Ramírez MÁ, Bolton CF (2016). "Review of the Diagnostic Challenges of Lambert-Eaton Syndrome Revealed Through Three Case Reports". Can J Neurol Sci. 43 (5): 635–47. doi:10.1017/cjn.2016.268. PMID 27412406.
- ↑ Gilhus NE (2016). "Myasthenia Gravis". N Engl J Med. 375 (26): 2570–2581. doi:10.1056/NEJMra1602678. PMID 28029925.
- ↑ Ozono K (2016). "[Diagnostic criteria for vitamin D-deficient rickets and hypocalcemia-]". Clin Calcium. 26 (2): 215–22. doi:CliCa1602215222 Check
|doi=
value (help). PMID 26813501. - ↑ Kamanyire R, Karalliedde L (2004). "Organophosphate toxicity and occupational exposure". Occup Med (Lond). 54 (2): 69–75. PMID 15020723.
- ↑ Pecina CA (2012). "Tick paralysis". Semin Neurol. 32 (5): 531–2. doi:10.1055/s-0033-1334474. PMID 23677663.
- ↑ Bane V, Lehane M, Dikshit M, O'Riordan A, Furey A (2014). "Tetrodotoxin: chemistry, toxicity, source, distribution and detection". Toxins (Basel). 6 (2): 693–755. doi:10.3390/toxins6020693. PMC 3942760. PMID 24566728.
- ↑ Kuntzer T, Hirt L, Bogousslavsky J (1996). "[Neuromuscular involvement and cerebrovascular accidents]". Rev Med Suisse Romande. 116 (8): 605–9. PMID 8848683.
- ↑ Laffont I, Julia M, Tiffreau V, Yelnik A, Herisson C, Pelissier J (2010). "Aging and sequelae of poliomyelitis". Ann Phys Rehabil Med. 53 (1): 24–33. doi:10.1016/j.rehab.2009.10.002. PMID 19944665.
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- ↑ Ho EL, Marra CM (2012). "Treponemal tests for neurosyphilis--less accurate than what we thought?". Sex Transm Dis. 39 (4): 298–9. doi:10.1097/OLQ.0b013e31824ee574. PMC 3746559. PMID 22421697.
- ↑ Falzarano MS, Scotton C, Passarelli C, Ferlini A (2015). "Duchenne Muscular Dystrophy: From Diagnosis to Therapy". Molecules. 20 (10): 18168–84. doi:10.3390/molecules201018168. PMID 26457695.
- ↑ Filippi M, Preziosa P, Rocca MA (2016). "Multiple sclerosis". Handb Clin Neurol. 135: 399–423. doi:10.1016/B978-0-444-53485-9.00020-9. PMID 27432676.
- ↑ Giang DW, Grow VM, Mooney C, Mushlin AI, Goodman AD, Mattson DH; et al. (1994). "Clinical diagnosis of multiple sclerosis. The impact of magnetic resonance imaging and ancillary testing. Rochester-Toronto Magnetic Resonance Study Group". Arch Neurol. 51 (1): 61–6. PMID 8274111.
- ↑ Riva N, Agosta F, Lunetta C, Filippi M, Quattrini A (2016). "Recent advances in amyotrophic lateral sclerosis". J Neurol. 263 (6): 1241–54. doi:10.1007/s00415-016-8091-6. PMC 4893385. PMID 27025851.
- ↑ Michelle EH, Mammen AL (2015). "Myositis Mimics". Curr Rheumatol Rep. 17 (10): 63. doi:10.1007/s11926-015-0541-0. PMID 26290112.
- ↑ Jain Foundation Inc: Research into Miyoshi/LGMD2B
- ↑ H.R. 717--107th Congress (2001): MD-CARE Act, GovTrack.us (database of federal legislation), (accessed Jul 29, 2007)
- ↑ Public Law 107-84, PDF as retrieved from NIH website
Template:Muscular Dystrophy
Template:PNS diseases of the nervous system
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