Muscle disorders Flashcards
what is muscle supplied with and how
acetylcholine
by the lower motor neuron via the neuromuscular juction
what does acetylcholine do
causes depolarisation of the muscle cells leading to contraction
what is the definition of myopathy
disease of muscle
what does myositis mean
inflammation of muscle
what is myalgia
pain arising from muscles
what is muscular dystrophy
a large group of hereditary disorders featuring abnormal muscle development of function
what are the clinical features of muscular dystrophy
vary depending on whether the condition is congenital or acquired and the distribution of the affected muscles
in general proximal weakness is experienced
gait can become waddling
pain may be present
what are typical features of proximal weakness
issues when rising from sitting, climbing stairs, lifting arms above head
weakness is not fatigable
reflexes may still be present
what is Gower’s sign
use of arms to provide support when standing
indicates weakness of pelvic girdle
typical in congenital muscular dystrophies such as Duchenne’s
what is Duchenne’s muscular dystrophy
x-linked condition where there is a mutation in dystrophin gene
manifestations typically emerge at 3-6yrs old
what are the characteristics of Duchenne’s
initial pelvic girdle weakness, then shoulder, trunk, arms
eventual development of scoliosis
characteristic calf pseudohypertrophy (muscle infiltration by fat)
associated with cardiac respiratory failure
typically wheelchair dependent by teens
what is scapular winging
sign of proximal weakness
seen when arms are outstretched forward
what is polymyositis
acquired inflammatory muscle disorder
what are the features of polymyositis
progressive proximal weakness
arises over weeks (subacute)
associated muscles pain
may be association with autoimmune disorder or cancer
what are the investigation results of polymyositis
creatine kinase is elevated
inflammatory pattern on muscle biopsy
