Muscular dystrophies are an inherited group of disorders characterized by the variable distribution of muscle wasting and weakness, onset depends on the age of onset, the pattern of inheritance, rate of progression, and clinical severity.
A muscular dystrophy is a group of diseases that cause progressive weakness and loss of muscle mass.
in muscular dystrophy, abnormal genes (mutations) interfere with the production of proteins needed to form healthy muscle
There are different types of muscular dystrophy, including the following:
Duchenne_muscular_dystrophy_(DMD:
> is one of the most severe forms of inherited muscular dystrophies. It is the most common hereditary neuromuscular disease and does not exhibit a predilection for any race or ethnic group. Mutations in the dystrophin gene lead to progressive muscle fiber degeneration and
Weakness
.> DMD is a genetic disease due to the mutation of the dystrophin gene, located on chromosome Xp21. It is inherited as an X- linked recessive trait; however, approximately 30% of cases are due to new mutations
> Mutations in the dystrophin gene result in diseases known as dystrophinopathies, which encompass Duchenne muscular dystrophy,
> DMD is inherited as an X-linked recessive manner, boys are more frequently affected than girls.
Becker_muscular_dystrophy:
Similar symptoms to Duchenne but with a later onset and slower progression; death usually occurs in the mid-forties.
Myotonic_(Steinert’s disease):
The myotonic form is the most common adult-onset form. It is characterized by an inability to relax a muscle once it has contracted. The muscles of the face and neck are often affected first. Symptoms also include cataracts, sleepiness, and arrhythmia.
Congenital: This type can be obvious from birth or before the age of 2 years. It affects girls and boys. Some forms progress slowly whereas others can move swiftly and cause significant impairment.
Facioscapulohumeral (FSHD):
Onset can be at almost any age but is most commonly seen during teenage years. The muscular weakness often begins in the face and shoulders. People with FSHD may sleep with their eyes slightly open and have trouble fully closing their eyelids. When an individual with FSHD raises their arms, their shoulder blades protrude like wings.
Limb_girdle: This variant begins in childhood or teenage years and first affects the shoulder and hip muscles. Individuals with the limb-girdle muscular dystrophy might have trouble raising the front part of the foot, making tripping a common problem.
Oculopharyngeal_muscular_dystrophy
: Onset is between the ages of 40 and 70 years. Eyelids, throat, and face are first affected, followed by the shoulder and pelvis.
So Let me start, the discussion over here for the most common form of muscular dystrophy is Duchenne muscular dystrophy
Pathophysiology : ( in brief )
Dystrophin is a large cytoskeletal protein that facilitates interactions between the cytoskeleton, cell membrane, and extracellular matrix. It is located at the plasma membrane in both muscle and non-muscle tissues. Dystrophin is a critical part of the dystrophin-glycoprotein complex (DGC), which plays an important role as being a structural unit of muscle. In DMD, both dystrophin and DGC proteins are missing, leading to excessive membrane fragility and permeability, dysregulation of calcium homeostasis, oxidative damage. These factors play a crucial role in muscle cell necrosis. As patients with DMD age, the regenerative capacity of the muscles appears to be exhausted, and connective and adipose tissue gradually replaces muscle fibers
Cause: .
Muscular dystrophy is caused by genetic mutations that interfere with the production of muscle proteins that are needed to build and maintain healthy muscles. The causes are genetic.
A family history of muscular dystrophy will increase the chance of it affecting an
Individual
Symptoms :
Early symptoms include :
waddling gait
Calf pseudohypertrophy
pain and stiffness in the muscles
difficulty with running and jumping
walking on toes
difficulty sitting up or standing
learning disabilities, such as developing speech later than usual
frequent falls
Later symptoms
Wheelchair Bounded
Respiratory Failure ( weak diaphragm muscle )
Scoliosis
Dilated Cardiomyopathy
Arrhythmias
Prognosis :
The prognosis is typically poor for affected patients. Patients are often wheelchair dependent by the age of 12 years. Death occurs as a result of respiratory or cardiac complications in the teens or 20s. Other causes of death are pneumonia, aspiration, or airway
Diagnosis_\evaluation
dystrophinopathy should be suspected in patients with symptoms of weakness,
characteristic physical examination and a possible family history of the disease.
Laboratory testing
Creatinine Kinase Measurements
Muscle Biopsy
Electromyography
Gene Analysis and
ECG Findings for Cardiomyopathy
Trouble_walking. Some people with muscular dystrophy eventually need to use a wheelchair
Trouble_using_arms. Daily activities can become more difficult if the muscles of the arms and shoulders are affected.
Shortening of muscles or tendons around joints (contractures). Contractures can further limit mobility.
Breathing_problems. Progressive weakness can affect the muscles associated with breathing. People with muscular dystrophy might eventually need to use a breathing assistance device (ventilator), initially at night but possibly also during the day.
Curved_spine (scoliosis). Weakened muscles might be unable to hold the spine straight.
Heart_problems. Muscular dystrophy can reduce the efficiency of the heart muscle.
Swallowing_problems. If the muscles involved with swallowing are affected, nutritional problems and aspiration pneumonia can develop. Feeding tubes might be an option.
Treatment :
Currently, there is no cure for muscular dystrophy. Medications and various therapies help slow the progression of the disease and keep the patient mobile for the longest possible time.
Glucocorticoid: GluGlucocorticoid therapy decreases the rate of apoptosis of myotubes and can decelerate myofiber necrosis. Prednisone is used in patients four years and older in whom muscle function is declining or plateauing.
Treatment with angiotensin-converting enzyme (ACE) inhibitors and/or beta-blockers is recommended. Early studies suggest that early treatment with ACE inhibitors may slow the progression of the disease and prevent the onset of heart failure
Pulmonary_Interventions
pulmonary function must be tested prior to the exclusive use of a wheelchair. This should be repeated twice a year once the patient reaches 12 years of age, must use a wheelchair or vital capacity is found to be less than 80% of predicted.
Physiotherapy_and_Orthotics_Intervention
General_exercises: A range of motion and stretching exercises can help combat the inevitable inward movement of the limbs as muscles and tendons shorten. Limbs tend to become fixed in position, and these types of activities can help keep them mobile for longer. Standard low-impact aerobic exercises such as walking and swimming can also help slow the disease’s progression.
Breathing_assistance: As the muscles used for breathing become weaker, it may be necessary to use devices to help improve oxygen delivery through the night. In the most severe cases, a patient may need to use a ventilator to breathe on their behalf.
Mobility_aids: Canes, wheelchairs, and walkers can help the person stay mobile.
Braces: These keep muscles and tendons stretched and help slow their shortening. They also give added support to the user when moving.
Note_source of content ... most of the content is taken from research article and paper and also from a few official websites
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