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 periodic P  metabolic  Progressive static  Dystrophy congenital

muscular dystrophy  are inherited myopathy characterized by progressive muscles weakness &degeneration &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

MD proteinageinheritancedisease dystrophin2y X linked duchenne beckers emerinchildh Emery-dreifuss sacroglycanAD/ARLGD birthARCong/CNS merosin..ARCong/noCNS AD/AR Distal MD ADbethlen Child& adult ADFSH 5 th dec ADoculodystrophy 2th,3th decade AD Myotonic type1 AD Myotonic type 2 desmminADmyofibrillar

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 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