Approach to myopathy
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Transcript Approach to myopathy
Approach to myopathy
Dr omid yaghini
MUSCLES DISORDERS
Definition:
Diseases involving the muscle fibers (myogenic)
Unlike: neuronopathies: secondary to LMN
Heterogenous etiology, genotype, phenotype…
No specific treatment for most of them
Myoblasts fusing to form large multi-nucleate
muscle cells
white = fast
(speed)
red = slow
(endurance)
ETIOLOGY / CLASSIFICATION
Inherited myopathies
– Muscular dystrophies
– Congenital myopathies
– Inherited channelopathies
– Periodic paralysis
– Inherited metabolic myopathies
Disorders of glycolysis
Disorders of oxidative metabolism
Lipid myopathies
Mitochondrial myopathies
Acquired myopathies
Inflammatory myopathies
Acquired metabolic myopathies
Toxic myopathies
Weakness
Constant
Longlife
Progressive
Dystrophy
fluctuation
acquired
MG
periodic P
metabolic
static
congenital
muscular dystrophy
are inherited myopathy characterized by
progressive muscles weakness
°eneration &subsequent replacement
by fibrous & fatty connective tissue
Historically were categorized by their:
Age onset /distribution of weakness&
pattern of inheritance
The genetic mutation &abnormal gene
product were defined for many of them
disease inheritance
duchenne
X linked
age
protein
2y dystrophin
beckers
MD
X linked
Emery-dreifuss
X linked
LGD
AD/AR
Cong/CNS
AR
Cong/noCNS
AR
Distal MD
AD/AR
bethlen
AD
FSH
AD
oculodystrophy
AD
5th dec
Myotonic type1 AD
2th,3th
decade
5-15
..
childh emerin
sacroglycan
birth
.. merosin
Child&
adult
Myotonic type 2 AD
myofibrillar
AD
desmmin
Congenital myopathy
Are
distinguished from dystrophy in
three respect:
Characteristic morphologic alteration
At birth
Non progressive
However there are exception to all
these generalization
Inheritance: are variable
c/p: hypotonia with subsequent developmental delay
Reduce muscles bulk, slender body build &long narrow face
Skeletal abnormalities: high arched palate ,pectus
exacavitum, kyphscliosis, dislocated hip, pes cavus)
Absent or reduced muscle stretch reflex
Weakness: limb girdle mostly, but distal weakness exist
CK &EMG may be normal
Muscle biopsy: the diagnostic method
Metabolic myopathy
Glucose/glycogen
metabolism
Fattay acid metabolism
mitochondrial
Calf Pseudohypertrophy
Gowers' Sign
“Climbing up himself”
Gowers’ sign
always denotes
proximal
muscle
weakness
Common Features:
Clinical:
Muscle weakness: main feature
Gower’s sign (proximaly dominating deficit)
Contractures
+/- severe: advanced stages
Pain: in inflamm. Disorders only
Atrophy (+/- pseudohypertrophy in X-linked)
Deformity: advanced disease
DTR: normal, diminished or absent
Tone: slightly or normal
Other systems may be involved
Common Features:
Laboratory Investigations:
CBC, LFT.. Normal
ESR: high in inflammatory only
U&E: abnormalities in some endocrinopathies and
periodic paralysis
C.K & aldolase: generaly: raised (normal in few
sittings: metabolic, endocrine…)
Lactic acid
Genetic study: location & type of chromozomal
abnormalities:
Common Features:
Neurophysiology
NCS: normal
EMG:
– Spontaneous activities +/- in inflammatory disorders
– Interferential tracing
– MUPs:
small A
Short D
polyphsics