Muscle Flashcards
fewer, but larger, motor unit action potentials on EMG
nerve injury with denervation and reinnervation
In myopathies, the muscle fibers
are not atrophic and angular
In myopathies, the number of motor units is
not decreased, unlike neurogenic disorders, because the number of motor neurons or axons are normal. The motor unit action potentials are smaller
elevated serum CK
may indicate myopathy
X-linked recessive inheritance disease
Duchenne Muscular Dystrophy - can cause Necrosis, Atrophy, Segmental fiber over-contraction, Connective tissue proliferation
antisense oligonucleotide that restores the reading frame
morpholino - may be future treatment for duchenne’s!
autosomal dominant diseases characterized by weakness and myotonia, they also can have involvement of multiple organs
Myotonic dystrophies
Measurement of serum lactate shows the lack of normal increase during exercise
McArdle’s Disease -muscle phosphorylase deficiency, can’t break down glycogen
Hyperparathyroidism might present with
severe weakness resembling amyotrophic lateral sclerosis
Hypothyroidism patients present with
muscle spasms but not weakness, and could have a very high serum creatine kinase levels, so this should be suspected in obese patients with hyperlipidemia and high serum creatine kinase
Myopathies from toxins or medications could be associated with either :
muscle fiber atrophy, vacuolization , myofibrillary degeneration , mitochondrial dysfunction, or fiber necrosis.
compound action potential becomes larger during fast stimulation rates
presynaptic - Eaton Lambert
amplitude becomes smaller during slow, repetitive stimulation
Myasthenia Gravis
treating myasthenia gravis
Anticholinesterase drugs such as pyridostigmine
Corticosteroids
Immunosuppressants:
azathioprine, cyclophosphamide, mycophenolate mofetil
Thymectomy
Plasma exchange
Immunoglobulin infusions
