Muscular Dystrophy: A Quick Overview

About this course

The term "muscular dystrophy" incorporates an assortment of hereditary disorders that lead to progressive, generalized disease of the muscle prompted by inadequate or missing glycoproteins in the muscle cell plasma membrane. Each form of muscular dystrophy has its own pattern of inheritance, onset period, signs and symptoms, and the rate at which muscle is lost. This course will overview muscular dystrophy, its types, how they are diagnosed, and interventions to help manage the condition.

Learning objectives

• Review the various types of muscular dystrophy and the areas of the body they are likely to affect.
• Review the pathophysiology as it relates to muscular dystrophy.
• Understand the diagnostic and laboratory data used to diagnose muscular dystrophy.
• Analyze nonpharmacological management of patients who are in the ambulatory and non-ambulatory stages of muscular dystrophy disease progression.
• Recognize nursing considerations that may be utilized when caring for a patient with muscular dystrophy.

Course outline

31 sections · finish in any order across devices

1. 1

   Introduction

   The term "muscular dystrophy" incorporates an assortment of hereditary disorders that lead to progressive, generalized disease of the muscle prompted by inadequate or missing glycoproteins in the muscle cell plasma membrane.1 It is a progressive condition that worsens over time, and often begins by

   4 min

2. 2

   Duchenne muscular dystrophy (DMD) is caused by a mutation of the dystrophin gene located on the X chromosome's small arm

   Duchenne muscular dystrophy patients typically present with progressive weakness of limb muscles, trunk muscles, and the diaphragm, leading to wasting, kyphoscoliosis, and severe respiratory problems.4 Most people afflicted with DMD succumb in their third decade of life due to respiratory complicati

   4 min

3. 3

   Myotonic Muscular Dystrophy

   Myotonic muscular dystrophy results from the impaired expression of the dystrophia myotonica protein kinase (DMPK).1 It is caused by an autosomal dominant abnormally expanded CTG trinucleotide repeat sequence located in the 3′ untranslated regions of the DMPK gene.1

   4 min

4. 4

   Limb-Girdle muscular dystrophy can be defined as a group of conditions that usually develop in late childhood or early a

   Some variants can progress quickly and be life-threatening, whereas others develop slowly.2 It affects males and females equally, and about 2 in 100,000 people of all ages.3 Limb-Girdle muscular dystrophy affects the upper arms and legs, heart, spine, hips, calves, and trunk.3

   4 min

5. 5

   Emery-Dreifuss Muscular Dystrophy

   Emery-Dreifuss muscular dystrophy is caused by an X-linked recessive defect in nuclear protein emerin at the Xq27-28 position.1 This variant can also result from an autosomal recessive or autosomal dominant defect in inner nuclear lamina proteins lamin A/C on chromosome 1.1

   4 min

6. 6

   Oculopharyngeal Muscular Dystrophy

   Oculopharyngeal muscular dystrophy is a type of muscular dystrophy that affects the extraocular and pharyngeal muscles is caused by an autosomal dominant GCG trinucleotide repeat resulting in deficient mRNA transfer from the nucleus.1 It does not usually develop until a person is between 50 and 60 y

   4 min

7. 7

   Distal muscular dystrophy is a class of muscular dystrophies that primarily affect distal muscles, which are those of th

   It begins in either childhood or adulthood and is slowly progressive. It does not affect the intellect and is not considered life-threatening.6 Distal muscular dystrophy is caused by a mutation in any of at least eight genes that affect proteins necessary to the function of muscles. It can be inheri

   4 min

8. 8

   Duchenne muscular dystrophy usually becomes apparent early in childhood.8 Affected children develop weakness and wasting

   As the disease progresses, muscle weakness and atrophy spreads to affect the lower legs, forearms, neck, and trunk.8 Another serious complication associated with DMD is weakness and deterioration of muscles in the rib cage.8 This can result in increased susceptibility to respiratory infections (pneu

   4 min

9. 9

   Becker Muscular Dystrophy

   Duchenne muscular dystrophy (DMD) and Becker muscular dystrophy (BMD) are often discussed together because they cause similar patterns of weakness and are inherited in the same way.7 However, BMD is less severe than DMD.7

   4 min

10. 10

    Myotonic Dystrophy

    Unlike other muscular dystrophies, muscle weakness in myotonic dystrophy is accompanied by myotonia (delayed relaxation of muscles after contraction) and by various other non-muscular symptoms.7 The first muscles to be affected by weakness are those of the face, neck, hands, forearms, and feet.7

    4 min

11. 11

    Limb-Girdle Muscular Dystrophy

    Although there are some common themes recognizable in the main types of LGMD, the age at onset, severity, and progression of symptoms associated with LGMD may vary greatly from case to case, even among members of the same family.10 The major symptoms of LGMD are:10

    4 min

12. 12

    Facioscapulohumeral Muscular Dystrophy

    On average, Facioscapulohumeral (FSH) muscular dystrophy progresses slowly, and the level of severity eventually is minimal enough to where patients usually retain the ability to walk and have a normal life span.7

    4 min

13. 13

    Congenital Muscular Dystrophy

    In most cases of congenital muscular dystrophy, the initial symptoms are present at birth or in the first few months.7

    4 min

14. 14

    Distal Muscular Dystrophy

    There are many different types of distal muscular dystrophies, each varying in their signs, symptoms, progression, and age of onset.13 For instance, in Welander Distal Myopathy, certain muscles of the hands and feet (intrinsic muscles and long extensors) and certain muscles of the fingers and toes (

    4 min

15. 15

    Pathophysiology

    In DMD, both dystrophin and Dystrophin-glycoprotein complex (DGC) proteins are missing, leading to excessive membrane fragility and permeability, dysregulation of calcium homeostasis, and oxidative damage.14

    4 min

16. 16

    Diagnosis

    A diagnosis of DMD is made based upon a thorough clinical evaluation, a detailed patient history, and a variety of specialized tests, including molecular genetic tests.8 If the genetic tests are not informative, surgical removal and biopsy of affected muscle tissue may reveal characteristic changes

    4 min

17. 17

    Creatinine Kinase Measurements

    Serum Creatinine Kinase (CK) is an enzyme that shows abnormally high levels when a muscle is damaged.8 Creatinine Kinase measurements are often elevated before the development of clinical symptoms. Levels peak by age two and can be more than 10 to 20 times above the upper limit of normal.14 Asymptom

    4 min

18. 18

    Muscle Biopsy

    A muscle biopsy will demonstrate endomysial connective tissue proliferation, scattered degeneration, and regeneration of myofibers, muscle fiber necrosis with a mononuclear cell infiltrate, and replacement of muscle with adipose tissue and fat.14 Various techniques such as immunostaining, immunofluo

    4 min

19. 19

    Gene Testing

    Molecular genetic tests involve the examination of deoxyribonucleic acid (DNA) to identify mutations, including deletions, duplications, or single-point mutations.8

    4 min

20. 20

    Duchenne Muscular Dystrophy Interventions

    No medical cure exists, and the disease has a poor prognosis.14 Treatments are aimed at the specific symptoms present in each individual.8 For instance; treatment options should include8

    4 min

21. 21

    Glucocorticoid Therapy

    Glucocorticoid therapy decreases the rate of apoptosis of myotubes and can decelerate myofiber necrosis.14 Studies have shown that glucocorticoid treatment is associated with improved pulmonary function, delayed development of scoliosis, reduced incidence and progression of cardiomyopathy, and overa

    4 min

22. 22

    Exercise And Nutrition

    Patients with DMD are recommended to take care of their physical health. Guidelines recommend all patients participate in a gentle exercise to avoid muscular atrophy. A combination of swimming pool and recreation-based exercises is recommended.14 However, activity should be reduced if myoglobinuria

    4 min

23. 23

    International Standards Of Care

    The international standards of care for DMD were first published in 2010 and have recently been updated and expanded.15

    4 min

24. 24

    Neuromuscular Management

    A neuromuscular specialist is the first-line medical advisor to patients and their families as they define and revise their individual care goals over time, helping them to personalize their risk-to-benefit analysis of therapeutic interventions.15 The advisor also addresses issues such as the transi

    4 min

25. 25

    Rehabilitation Management

    During the patient's lifetime, comprehensive, multidisciplinary examinations should be conducted regularly, including standardized assessments, such as range of motion, the North Star Ambulatory Assessment, timed function tests, and muscle function measures.15

    4 min

26. 26

    Respiratory Management

    During the ambulatory stages, spirometry (functional ventilation capacity, [FVC]) or sleep studies are only recommended when suspicious clinical symptoms appear.15

    4 min

27. 27

    Orthopedic Management

    During the early and late ambulatory stages:15

    4 min

28. 28

    Cardiac Management

    In the ambulatory stages:15

    4 min

29. 29

    Risk For Falls

    Nursing interventions include:16

    4 min

30. 30

    Risk For Injury

    Nursing interventions include:16

    4 min

31. 31

    Conclusion

    During the last 20 years, the number of preclinical, animal-based studies, and clinical trials in DMD has risen significantly.15 Based on the growing knowledge of the genetics and pathophysiology of this disease, the following therapeutic pathways have been taken via molecular-genetic methods or wit

    4 min

This course satisfies

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References and resources

• LaPelusa A, Kentris M. Muscular Dystrophy. PubMed. Published 2021. https://www.ncbi.nlm.nih.gov/books/NBK560582/
• NHS Choices. Overview - Muscular Dystrophy. NHS. Published 2019. https://www.nhs.uk/conditions/muscular-dystrophy/
• CDC. What is Muscular Dystrophy? | CDC. Centers for Disease Control and Prevention. Published November 27, 2019. https://www.cdc.gov/ncbddd/musculardystrophy/facts.html#:~:text=Muscular%20dystrophies%20are%20a%20group
• Biressi S, Filareto A, Rando TA. Stem cell therapy for muscular dystrophies. Journal of Clinical Investigation. 2020;130(11):5652-5664. doi:10.1172/jci142031
• Emery-Dreifuss Muscular Dystrophy (EDMD) - Causes / Inheritance | Muscular Dystrophy Association. Muscular Dystrophy Association. Published December 18, 2015. https://www.mda.org/disease/emery-dreifuss-muscular-dystrophy/causes-inheritance
• Diseases - Distal Myopathies - Top Level. Muscular Dystrophy Association. Published December 18, 2015. https://www.mda.org/disease/distal-myopathies
• Services D of H & H. Muscular dystrophy. www.betterhealth.vic.gov.au. Accessed November 11, 2022. https://www.betterhealth.vic.gov.au/health/conditionsandtreatments/muscular-dystrophy#facioscapulohumeral-dystrophy-fsh
• Duchenne Muscular Dystrophy. NORD (National Organization for Rare Disorders). https://rarediseases.org/rare-diseases/duchenne-muscular-dystrophy/#standard-therapies
• Salari N, Fatahi B, Valipour E, et al. Global prevalence of Duchenne and Becker muscular dystrophy: a systematic review and meta-analysis. Journal of Orthopaedic Surgery and Research. 2022;17(1). doi:10.1186/s13018-022-02996-8
• Limb-Girdle Muscular Dystrophies - NORD (National Organization for Rare Disorders). NORD (National Organization for Rare Disorders). Published 2015. https://rarediseases.org/rare-diseases/limb-girdle-muscular-dystrophies/
• Emery Dreifuss Muscular Dystrophy. NORD (National Organization for Rare Disorders). https://rarediseases.org/rare-diseases/emery-dreifuss-muscular-dystrophy/
• Oculopharyngeal Muscular Dystrophy. NORD (National Organization for Rare Disorders). https://rarediseases.org/rare-diseases/oculopharyngeal-muscular-dystrophy/
• Distal Myopathy - NORD (National Organization for Rare Disorders). NORD (National Organization for Rare Disorders). Published 2019. https://rarediseases.org/rare-diseases/distal-myopathy/
• Venugopal V, Pavlakis S. Duchenne Muscular Dystrophy. PubMed. Published 2020. https://www.ncbi.nlm.nih.gov/books/NBK482346/
• Korinthenberg R. A new era in the management of Duchenne muscular dystrophy. Developmental Medicine & Child Neurology. Published online December 16, 2018. doi:10.1111/dmcn.14129
• Muscular Dystrophy Nursing Diagnosis and Nursing Care Plan. NurseStudy.net. Published January 17, 2021. https://nursestudy.net/muscular-dystrophy-nursing-diagnosis/

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