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
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