approach to myopathy dr omid yaghini muscles disorders definition: diseases involving the muscle...
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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 fluctuation
Longlife acquired MG periodic P metabolic
Progressive static Dystrophy 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
MDprotein age inheritance disease
dystrophin 2y X linked duchenne
.. 5-15 X linked beckers
emerin childh X linked Emery-dreifuss
sacroglycan AD/AR LGD
birth AR Cong/CNS
merosin .. AR Cong/noCNS
AD/AR Distal MD
AD bethlen
Child&adult
AD FSH
5th dec AD oculodystrophy
2th,3th decade
AD Myotonic type1
AD Myotonic type 2
desmmin AD myofibrillar
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
Clinical: Muscle weakness: main feature
Gower’s sign (proximaly dominating deficit)Contractures +/- severe: advanced stagesPain: in inflamm. Disorders onlyAtrophy (+/- pseudohypertrophy in X-linked) Deformity: advanced diseaseDTR: normal, diminished or absentTone: slightly or normal Other systems may be involved
Common Features:
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: normalEMG:
– Spontaneous activities +/- in inflammatory disorders– Interferential tracing
– MUPs: small A Short D
polyphsics