Myopathies Flashcards
What is myotonia?
Failure of muscle relaxation after use
Due to Cl channels
What are fasciculations?
Fine, fast, spontaneous twitches
Name inflammatory myopathies?
Polymyositis
Dermatomyositis
Inclusion body myositis
Feature of polymyositis?
Symmetrical, progressive, proximal weakness
Weeks to months
Increased CK - responds to steroids
Features of dermatomyositis?
Clinically similar to polymyositis but with skin lesions - heliotrope rash on face, shawl sign of back and shoulders, gottrons papules
What is inclusion body myositis ?
Slowly progressive weakness from >50 years old
Characteristic thumb sparing
What causes myotonic dystrophy?
Autosomal dominant Cl- channelopathy
Features of myotonic dystrophy?
Myotonia Weakness- hand/ foot drop Cataracts Ptosis Frontal balding Cardiac defects Most patients die middle aged
Commonest muscular dystrophies?
Duchennes
Beckers
What is rhabdomyolysis?
Dissolution of muscle - damage to skeletal muscle -> leakage of large quantities of toxic intracellular contents into plasma
Causes of rhabdomyolysis ?
Crush injuries
Toxins
Post convulsions
Triad of features in rhabdomyolysis?
Myalgia
Muscle weakness
Myoglobinuria
