Proximal Myopathy
Overview
Signs of Proximal Myopathy
General Signs
- Proximal muscle wasting - biceps, deltoids, quadriceps, buttocks
- Symmetrical proximal weakness - particularly the shoulder and hip muscles
- Trendelenberg gait - dropping of the affected side during the stance phase
- Trendelenberg test - dropping of the affected hip on standing on the opposite leg
Signs Suggesting a Cause
- Dermatomyositis - heliotrope rash, Gottron's papules
- Paraneoplastic syndrome - surgical scars, e.g. in the chest
Causes of Proximal Myopathy
Congenital
- Muscular dystrophy - e.g. Duchenne's, Becker's, Emery-Dreyfuss, limb girdle, fascioscapulohumeral
- Metabolic myopathies - e.g. glycogen and lipid storage disorders
Acquired
- Inflammatory myositis - polymyositis, dermatomyositis
- Paraneoplastic syndrome
- Infection - Lyme disease, HIV, infectious pyomyositis, trichinosis, cysticercosis, coxsackievirus
- Endocrine - thyroid disease, Cushing's, acromegaly, hypopituitarism
- Metabolic - periodic paralysis
- Toxins - alcohol, steroids, statins, cocaine
- Sarcoidosis
Proximal Muscles of the Upper Limb
- Deltoids
- Biceps
- Triceps
- Brachioradialis
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