diseases of muscle
Terms
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- connective tissue which encloses muscle as a whole
- epimysium
- collagenous septae which extend inward from epimysium to surroung groups of muscle fibers
- perimysium
- connective tissue which surrounds individual muscle fibers
- endomysium
- histochemical stain which reflects distribution of sarcoplasmic reticulum and mitochondria
- NADH tetrazolium reductase
- 2 stains for glycogen storage disease
- myophosphorylase and periodic acid Schiff (PAS)
- define group atrophy
- atrophy of adjacent motor units as a result of acute rapidly progressive neuropathy
- target fibers
- seen in 20% of denervation, detected with NADH tetrazolium reductase as fibers with a central zone of pallor surrounded by darker condensed zone
- amyotrophic lateral scerosis, what degenerates?
- degeneration of corticospinal tracts and anterior horn cells
- amyotrphic lateral sclerosis clinical picture
- progressive paralysis accompanied by spacisity and hyperactive tendon reflexes. death from aspiration pneumonia in 2-6 yrs, sensation and intellect unaffected
- amyotrophic lateral sclerosis muscle biopsy
- changges of chronic neuropathy, with small angular fibers, fiber type grouping, and large group atrophy
- infantile spinal musclular atrophy, what is etiology, cns pathology?
- degeneration of anterior horn cells. genetic etiology, autosomal recessive
- infantile spinal muscular atrophy presentation
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congenital hypotonia, progressive, death in a few years
rarer form b/t 6 and 24 months - infantile spinal muscular atrophy muscle biopsy
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acute neuropathy, scattered small fibers nad extensive group atrophy
chronic atrophy seen in milder form, with scattered small angular fibers and fiber type grouping - poliomyelitis cns damage
- anterior horn cells
- poliomyelitis clinical course
- acute illness, fever, vomiting, diarrhea, sore throat, headache. may result in death, paralysis, or may be mild with recovery
- poliomyelitis muscle biopsy
- in acute stages little pathologic change, in atrophied paralyzed muscles extensive fiber atrophy with occasional persisting motor units with compensatory hypertrophy
- peroneal muscular atrophy site of degeneration
- periphereal nerves and nerve roots, involvement restricted to distal limb muscles and begins in feet
- clinical course peroneal muscualr atrophy
- onset in late childhood or adult, slowly progressive. sensation lost as well as motor fx
- muscle biopsy of peroneal muscular atrophy
- changes of chronic neuropathy with small angular fibers, type grouping, and group atrophy
- duchenne muscular dystrophy histology
- muscular atrophy and infiltration of the muscle by fat
- pathogeneis of duchenne muscular dystrophy
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delition of gene for dystrophin
dystrophin links subsarcolema to extracellular glycoprotein that binds laminin.
fibers lack interaction btween sarcolema and extracellular matrix - myotonic muscular dystrophy symptoms
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myotonia--inability to relax a muscle after a strong contraction
progresive muscle weakness and wasting
associated with frontal balding, catarcts, gonad atrophy, endocrine dysfunction, conduction abnormalities in heart - polymyositis and dermatomyosytis clinical course
- begins as symmetrix proximal weakness that develops insidiously. may involve skin lesions.,
- inclusion body myositis
- refractory to therapy, recognized by electron microscopy by the presence of filamentous inclusions in myofibers
- trichinosis
- infection with trichinella spiralis, nematode iin pori. migrates to encyst skeletal muscle. fever fatigue, muscle tenderness, eosinophilia
- type II glycogenosis (pompe's disease; acide maltase deficiency) presentation, involvement, biopsy, biochemical analysis
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floppy baby, cardiomegaly, death in 1st year
increased glycogen in muscle
absence of acid maltase, a lysozyme enzyme - type v glycogenosis (mcardles' disease, myophosphorylase deficiency_ presentation, clinical features, biopsy
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stiffness, weakness, muscle pain with exercise
serum lactate fails to rise with exercise
normal life span
increased glycogen in muscle
negative for myophosphorylase - myasthenia gravis pathogenesis
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immunologic attack on acetylcholine receptor, t cells activate b cells to produce antireceptor antibodies
40% associated thyoma and removal may cure - word for dissolution of skeletal muscle fibbers with release of myoglobin into circulation
- rhabdomyolysis