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Muscle

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									 Muscular
dystrophy
Voluntary             Involuntary
            muscles
    Muscular dystrophy
   Muscular dystrophy (MD) is a group of rare
    inherited muscle diseases in which muscle fibers
    are unusually susceptible to damage.

   Muscles, primarily voluntary muscles, become
    progressively weaker

   In some types of muscular dystrophy, heart
    muscles, other involuntary muscles and other
    organs are affected
       Duchenne muscular
       dystrophy (Xp21.2)
   Type of muscular dystrophy that are due to
    a genetic deficiency of the protein
    dystrophin

   severe form of muscle dystrophy

   It occurs mostly in young boys and is the
    most common form of MD that affects
    children.
Duchenne muscular dystrophy
   X-linked
    inheritance
    1/3500 live male
    births
Dystrophin
                     Dystrophin

   a large (427 kD) cytoskeletal protein
   localizes to the inner face of the skeletal muscle
    membrane
   Dystrophin: likely plays a critical role in establishing
    connections between the internal, actin-based
    cytoskeleton and the external basement membrane
   Its absence may lead to increased membrane
    fragility
Duchenne muscular dystrophy

   Difficulty getting up
    from a lying or sitting
    position
   Weakness in lower leg
    muscles, resulting in
    difficulty running and
    jumping
   Waddling gait
   Mild mental retardation,
    in some cases
Difficulty getting up
from a lying or sitting
position
Clinical features
Normal at birth
Delayed walking
Clumsiness
Weakness begins at
pelvic girdle
Extends to shoulder
girdle
Pseudohypertrophy
Clinical features
Heart failure
Arrythmiast
Gower’s sign
Serum creatine kinase - ↑
Morphology
Variation in size of
muscle fibers
Degeneration, necrosis &
phagocytosis of muscle
fibers
Morphology

             Later stages :
             Muscle
             replaced by
             fat
 Most die by their late teens or early
  20s, often from pneumonia,
  respiratory muscle weakness or
  cardiac complications.
 Some people with Duchenne MD may
  exhibit curvature of their spine
  (scoliosis).
    Becker's muscular dystrophy

   This type of muscular dystrophy is a
    milder form of muscular dystrophy
   It generally affects older boys and
    young men, and progresses more
    slowly, usually over several decades.
   Signs and symptoms of Becker MD are
    similar to those of Duchenne.
   The onset of the signs and symptoms
    is generally later, from age 2 to 16
Waddling gait
In the late stages of muscular
dystrophy, fat and connective tissue
often replace muscle fibers.
DMD
Orthopaedic management of
patients with Duchenne's
muscular dystrophy
Diagnosis:
Symptoms of muscle dystrophy
    Duchenne Muscular Dystrophy (severe form)
      Becker Muscular Dystrophy (mild form)


          Do a muscle biopsy
                Do a creatinine kinase
                         test
       Myotonic dystrophy
   This form of muscular dystrophy produces
    stiffness of muscles and an inability to
    relax muscles at will (myotonia)
   Autosomal dominant disorder
   Trinucleotide repeat disorder
Myotonic dystrophy
   This form of MD can affect children,
    it often doesn't affect people until
    adulthood.
   It can vary greatly in its severity.
   Muscles may feel stiff after using
    them.
   Progression of this form of MD is
    slow.
Myasthenia
  gravis
Definition
Autoimmune disease

Neuromuscular function disorder

Immune mediated loss of acetylcholine receptors
Epidemiology
3 in 100,000
< 40 yrs F>M
Older patients F=M
Thymic hyperplasia – 65%
Thymoma – 15%
Normal   Myasthenia Gravis
Clinical features
Drooping eyelids - ptosis
Clinical features
Double vision – diplopia
Fluctuating generalized weakness

       Normal            Myasthenia gravis
Clinical features
Respiratory compromise – major cause of
mortality
Improvement in strength – administration of
anticholinesterase agents
Electrophysiology - ↓ in motor response with
repeated stimulation
Nerve conduction studies - normal
Morphology
Usually unrevealing
Disuse changes
Fiber atrophy
Treatment
Anticholinesterase drugs
Prednisone
Plasmapheresis
Resection of thymoma if present
NERVE TISSUE
       Gullian barre syndrome
• Life threatening disease of the nervous
  system
• 1-3 cases per 100000 persons
              Pathogenesis
• Two third cases preceeded by influenza like
  illness
• Infections- Campylobacter jejuni ,CMV,EBV
              Clinical features
•   Ascending paralysis
•   Deep tendon reflexes disappear
•   Nerve conduction velocity is slow
•   CSF proteins ↑
             MORPHOLOGY
• Histopathology
• Inflammation of the peripheral nerve -
  lymphocytes ,macrophages ,plasma cells
• Segmental demyelination –primary lesion

								
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