Skeletal muscles disease and disorder


Normal Muscles
myopathies
Muscular Atrophy
Muscular Dystrophy
Inflammation of muscle (Myositis)
Disorders of Neuromuscular Transmission
Content

 It is composed of
fascicles of muscle
fibers (myofibrils)
that represent the
cellular unit.
 A myofibril is a
long, cylindrical,
multinucleate cell
that is the
contractile unit of
the muscle.
Normal muscles


Diseases and damage the brain or nerves that
stimulate muscles and disorders of muscle fibers.
 "Myopathy" simply means muscle disease (myo-
Greek "muscle" + patho-Greek "suffering").
Causes:
o Loss of innervation (neurogenic injury).
o Disuse.
o Old age.
o Primary myopathies (inflammatory or others).
Myopathies


 General clinical considerations- family history, age of
onsets, history of drugs, distribution of muscle
weakness and rate of progression.
 Special investigation of neuromuscular electrical
activity (electromyography).
 Laboratory test:-
I. muscle biopsy.
II. serum enzymes (CK).
III. chromosomal analysis.
Muscle disease- Diagnosis

• Muscular Atrophy.
• Muscular Dystrophy.
• Inflammation of muscle
(Myositis).
• Disorders of Neuromuscular
Transmission.
Muscles
disease
/
disorder

 defined as a decrease in the
mass of the muscle; it can be a
partial or complete wasting
away of muscle.
 and is most commonly
experienced when persons
suffer temporary disabling
circumstances such as being
restricted in movement and/or
confined to bed as when
hospitalized.
 this leads to muscle weakness,
since the ability to exert force is
related to mass.
1.Muscular atrophy


 Normal muscle which is
overused will end up weak or
spasm until rested.
 In severe cases of overuse,
especially where movements are
strong and erratic as might occur
during convulsions, damage to
muscle cells may result.
 Severe damages muscle cells
release myoglobin, a condition
known as rhabdomyolysis.
Rhabdomyolysis

 A group of genetic diseases that cause progressive
skeletal muscle weakness, defects in muscle proteins, and
the death of muscle cells and tissue.
 Duchenne Muscular Dystrophy (DMD) is the most
common.
2.Muscles dystrophy

 the most common and most rapidly
progressive childhood muscle disease .
 The disease is due to the absence of a
gene located on the short arm of the X
chromosome at the Xp21 site.
 It usually affects only boys .
 The first sign of the disease is difficulty
in walking from 2 to 6 years old.
 Later , the child falls frequently and can
not run. Walking and standing become
more difficult At adolescence a
wheelchair is needed. The disease
eventually affects most muscles of the
body.
Duchenne Muscular Dystrophy
(DMD)


 Steroids  main treatment option
 Vaccination to prevent Pneumonia & Influenza
 Screening (by Echo/MRI) at around 6 years age, and
treatment of Cardiomyopathy.
 Lung function testing at around 9 - 10 years age and
assisted ventilation if needed.
 Periodic monitoring of Vitamin D levels & diet rich in
Calcium & Vit. D.
 Physical therapy, leg braces
 Surgery for correction of contractures & scoliotic
deformities
Management


 The primary focus of Myositis Support and
Understanding is rare muscle diseases which are
referred to as “Idiopathic Inflammatory Myopathies”
or “Acquired Myopathies,” meaning muscle diseases
which are typically not inherited and are caused by
the immune system attacking muscles, connective
tissue, blood vessels, lungs, and/or the skin.
 All forms of Idiopathic Inflammatory Myopathies
are rare diseases.
Inflammation of muscle
(Myositis)


 Polymyositis (PM) presents with
muscle weakness affecting the
proximal skeletal muscles, those
closest to the bodies core and used
for movement. These muscles can
include the neck, hips, back, and
shoulders. Muscle weakness may
happen over days, weeks, or
months. Myositis antibodies can
aid in a diagnosis, and in some
cases, may aid in predicting
disease course and potential
treatment outcomes. Lung disease
and, to a lesser extent, cancer, may
accompany PM.
Polymyositis (PM)

 Symptoms vary from patient to patient.
o Proximal muscle weakness (muscles closest to the body’s core),
affecting upper arms, shoulders, thighs, hips, and neck.
o Symmetrical muscle weakness (same on both sides of the body).
o Arthritis.
o Muscle pain (myalgia).
o Difficulty swallowing (dysphagia).
o Fatigue (can be extreme and life-altering).
o Low-grade fever.
o Labored breathing (dyspnea).
o A hoarse or changing voice when speaking (dysphonia).
o Difficulty maintaining enough air to finish a sentence.
o Difficulty turning in bed, getting up from a seated position, and
raising arms over the head.
Symptoms of Polymyositis


 Myasthenia Gravis is a clinical syndrome resulting
from failure of neuromuscular transmission due to
blockage and destruction of acetylcholine receptors
by autoantibody.
 Myasthenia gravis is therefore an organ-specific
autoimmune disease.
 MG is characterized by muscle weakness that is
typically aggravated by repeated contraction.
Disorders of Neuromuscular
Transmission

 Muscle with the smallest motor units are affected first, the
most typical clinical presentation being weakness of
ocular muscles causing drooping of the eyelid.
 The disease sometimes progress to include facial muscles,
limb girdle muscles, and respiratory muscles
Myasthenia Gravis


 Edrophonium (Tensilon)-short acting drug produce
immediate improvement in muscle weakness when
administered IV .
 EMG-↓ in amplitude of muscle action potentials
when muscle is subjected to repeated voluntary
contraction.
 Serum assay for anti-Ach receptor antibody.
Diagnosis of MG

Skeletal muscles disease and disorder

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