الفهرس 
Epidemiology&Clinical variant of Inflammatory myopathyOnly 14 pages are availabe for public view
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Abstract
The idiopathic inflammatory myopathies are a group of muscle disease characterized by chronic inflammation and weakness of skeletal muscles.
Studies revealed that incidence ofIdiopathic inflammatory myopathies ranges from 0.5-8.4 cases per milion population in the united states of america. The same study revealed that Polymyositis is more common within the black population , it was estimated that polymyositis is 5 times more common black patients and dermatomyositis is 3 times more common in black patients , Yet polymyositis is less common among japanese .
Polymyositis and dermatomyositis are twice more common in women , while inclusion body myositis is twice more common in men.
Dermatomyositis and polymyositis are characterized mainly by progressive symmetric proximal muscle weakness that develop over weeks to months , yet no sensory loss or ptosis with sparing of extraocular muscles , however , distal muscle weakness may occur early in inclusion body myositis .
Deep tendon reflexes are normal except in severely weakened muscles such as respiratory and trunk muscles .
Respiratory muscle weakness may occur necessitating the need for assisted ventilation .
Pharyngeal muscle weakness may occur in advanced cases of idiopathic inflammatory myositis causing dysphagia , nasal speech , hoarseness of voice and nasal regurgitation of food .
Idiopathic inflammatory myositis mimic anumber of diseases in clinical picture including limb girdle dystrophy and fascioscapulohumeral dystrophy , metabolic , mitochondrial , endocrine and drug induced myopathy .
The presence of certain physical signs such as waddling gait , extraocular muscle weakness , scapular winging and calf hypertrophy should raise the suspicion of another aetiology.