NMJ and Muscle Diseases Flashcards
presentation of lmn
fasciculations (spontaneous discharges)
fibrillations (1 single muscle discharge, unsynchronized)
most common type of childhood disease
duchenne muscular dysthrophy
disease progression of duchenne muscular dystrophy
ascending pattern
3-5: difficulty running, jumping, hopping, gower maneuver
6-8: toe walking
8-10: need braches, joint contractures
12-16: wheelchair-dependent or bed bound, contractures, scoliosis
16-18: systemic manifestations, dec pulmo fn
lab findings in dmd
increased ck 20-100x
muscle biopsy is standard of diagnosis
immunoperoxidase stain: absent dystrophic in sarcolemma (absent stain)
treatment for dmd
supportive
prednisone
eteplirsen
presentation of beckers muscular dystrophy
ambulatory beyond 15 yo
cardiomyopathy
myalgias
myoglobinuria
lab findings in beckers muscular dystrophy
similar to dmd but less severe
REDUCED amount of dystrophin (not absent)
presentation of central core myopathy
generalized weakness or hypotonia
delayed motor milestones
affects proximal muscles (legs > arms)
minimal facial/neck flexor/ bulbar symtptoms
lab findings in central core myopathy
normal cks
myopathic pattern in emg
muscle biopsy with structural alteration within the center of the muscle fiber
forms of nemaline myopathy
mutation in tropomyosin, nebulin, troponin t, and actin
severe infantile form, static/slowly progressive form, adult onset form
lab findings in nemaline myopathy
type 1 fiber predominance and hypotrophy
nemaline rods on sarcomela
clinical features of myotonic dystrophy 1
distal limb weakness progressing proximally neck flexor involvement sometimes bulbar muscle dysarthria myotonia
specific features in myotonic dystrophy 1
cataracts frontal balding testicular atrophy impotence hyperinsulinemia
lab tests for myotonic dystrophy 1
normal ck
muscle biopsy: pyknotic nuclear clumps, agulated fibers
emg: fibrillating, pws, myopathic mups, myotonic discharges
types of myotonia
percussion myotonia: thenar muscle delayed relaxation
grip release myotonia: delayed release of grip
tongue myotonia
hypokalemic vs hyperkalemic periodic paralysis
table 6
largest group of aceuqired and treatable cause of skeletal muscle weakness
inflammatory myopathies
types of inflammatory myopathies
polymyositis, dermatomyositis, inclusion body myositis
pathogenesis of inflammatory myopathies
triggering events causing autoimmune or t-cell mediated reaction
complement mediated microangiopathy and muscle ischemia –> necrosis, degeneration, phagocytosis of muscle fibers