Wk 4 Muscle Diseases Flashcards
Neurogenic Atrophy
results in loss of checkerboard pattern of type 1 and type 2 muscle fibers, reinnvervation causes groups of muscles to be innervated in clumps
Main molecule affected in muscular dystrophies and function
dystrophin–responsible for binding myofibrils to cell membrane
Duchenne Muscular Dystrophy (DMD) pathology
complete lack of dystrophin
Becker Muscular Dystrophy (BMD)
modified dystrophin present
Female carries of muscular dystrophy genes–what is so special?
elevated CK
Genetics of muscular dystrophies
X-linked, 1/3 novel mutations
What is myotomia
sustained involuntary contraction of a group of muscles
Genetics of inherited myotomias
trinucleotide repeats
Malignant hyperpyrexia pathology
group of diseases associated with ion channel mutations–> increased cytosolic Ca2+
malignant hyperthermia
Dermatomyositis pathology
immunologic injury to small vessels in sk. muscle
often paraneoplastic syndrome
Polymyositis
similar to dermatomyositis but w/o skin involvement
Inclusion body myositis
begins in distal muscles (dermatomyositis and polymyositis begin in proximal muscles)
Thyrotoxic myopathy
hyperthyroidism => hypertrophy (esp. around eyes)
hypothyroidism => atrophy
Ethanol myopathy
acute rhabdomyolytis causes rapid breakdown of sk. muscle
Drug induced myopathies, most common
Cushings Syndrome
