Muscular Dystrophy

What is muscular dystrophy (MD)?

Muscular dystrophy is a group of diseases that involves a progressive loss of muscle mass and weakness of muscles leading to life-threatening conditions.

There are different types of MD:

• Duchenne MD – seen in younger boys
• Myotonic dystrophy – progressive muscle weakness or muscle wasting where smaller muscles are affected first. It affects both men and women with equal frequency.
• Facioscapulohumeral MD – affects the face, shoulders, arms and calves
• Becker MD – mostly affects boys, but less severe than Duchenne MD
• Limb-girdle MD – affects the big muscles like shoulder and hip muscles
• Oculopharyngeal MD – begins in the later years of life (50 years and above) and affects the muscles of eyes and throat
• Emery-Dreifuss MD – begins in adolescence and involves muscle contractions in arms, neck and feet

What are its main signs and symptoms?

Early symptoms include:

• Abnormal gait
• Pain and stiffness in the muscles
• Difficulty in running and jumping
• Difficulty sitting up or standing
• Walking on toes
• Learning and speech disabilities
• Frequent falls

Progressive symptoms include:

• Limited movements
• Breathing problems
• Spinal curvature
• Weakened heart muscles
• Swallowing problems
• Reduced life expectancy

What are the main causes?

MD is a genetic disorder that occurs due to mutations in genes that are responsible for the production of a muscle protein called dystrophin. A family history of muscular dystrophy increases the chances of an individual being affected.

How is it diagnosed and treated?

Diagnosis:

• Investigation of symptoms like difficulty in standing, lifting objects or ability to play sports
• Analysing the family history
• Physical examination     
• Blood test to assess creatine kinase that is released in the blood if muscles are damaged and to look for antibodies against muscle cells
• Electrical test on muscle and nerves to observe muscle contractions and nerve impulses
• Muscle biopsy that involves removing a sample of muscle tissue to examine for proteins under microscope
• MRI and CT scan to view detailed images of the affected muscles and identify the extent of muscle damage
• Chest X-ray, ECG and 2D echocardiogram to monitor breathing and heart symptoms
• Genetic testing to check for mutations in the dystrophin gene

Treatment:

• Currently, there is no cure for MD.
• Medications like corticosteroids and heart medications might help in slowing the progression of MD and alleviate symptoms. Eteplirsen is a new drug identified to treat Duchenne MD.
• General exercises can combat the inevitable inward movement of limbs.
• Breathing assistance to improve oxygen delivery
• Mobility aids that help the patient stay mobile
• Braces help keep the muscles and tendons stretched and flexible.
• Surgery is recommended to correct spinal curvature.

1. National Health Service [Internet]. UK; Muscular dystrophy.
2. MedlinePlus Medical Encyclopedia: US National Library of Medicine; Muscular Dystrophy.
3. Center for Disease Control and Prevention [internet], Atlanta (GA): US Department of Health and Human Services; Muscular Dystrophy.
4. National Institute of Neurological Disorders and Stroke [internet]. US Department of Health and Human Services; Muscular Dystrophy Information Page.
5. Better health channel. Department of Health and Human Services [internet]. State government of Victoria; Muscular dystrophy.