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5 clinical signs of diffuse muscle disease.
short stride/ choppy gait, weakness, decreased muscle tone, atrophy (often severe and rapid), "elephant on a beach ball" posture
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4 blood values that are commonly elevated with diffuse muscle disease?
CK, ALT, LDH, cardiac troponin
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Why does a normal value for CK not rule out diffuse muscle disease?
CK is only elevated when muscles are ruptured through degeneration or necrosis; there are many inflammatory muscle diseases that do not cause rupture and are therefore accompanied by normal CK
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How does an electromyocardiogram (EMG) work?
measures spontaneous electrical activity of muscle; under general anesthesia, muscles should have low/no spontaneous electrical activity (unless there is pathology)
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How can you describe the different types of spontaneous electrical activity found on EMG?
fibrillation potentials, positive sharp waves, myotonic potential
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EMG cannot distinguish __________ from ___________; _________ is required to make a specific diagnosis.
nerve dz; muscle dz; biopsy
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What are the 2 types of polymyositis, and in what species are they most common?
autoimmune- dogs, infectious- cats
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With polymyositis, there is ___________ inflammation that is primarily ___________.
mixed; lymphocytic
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With infectious polymyositis, what 2 etiologic agents are most common?
toxoplasma, neospora
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Immune-mediated polymyositis is ___________ inflammation of multiple muscle groups; it is diagnosed by...
idiopathic; muscle biopsy and ruling out infectious causes.
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Autoimmune polymyositis affecting laryngeal mm may present with ______________; affecting laryngeal and pharyngeal mm may present with ___________; with esophageal involvement, may present with ___________.
increased upper airway sounds;change to the tone of bark; passive vomiting
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How do you treat immune-mediated polymyositis?
immunosuppressive drugs
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Masticatory myositis is a(n)____________ inflammatory condition of the muscles innervated by the ______________.
autoimmune; mandibular branch of the trigeminal nerve
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The onset of masticatory myositis is relatively ___________, and it usually presents as ____________.
acute; inability to open the jaw
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Masticatory myositis involves atrophy of... (3)
masseter, digastricus, and temporalis mm.
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Describe the pathogenesis of masticatory myositis.
autoimmune attack on 2M muscle fibers, which are unique to the muscles of mastication.
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Acutely, masticatory myositis involves __________ muscles; chronically, there is _____________.
swollen, painful; marked atrophy and fibrosis
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How do you diagnose masticatory myositis? (2)
serum 2M antibody titer, temporalis muscle biopsy
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How do you treat masticatory myositis? (2)
immunosuppressive prednisone, supportive care
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Steroid myopathy can result from ____________ or ___________ and presents as _____________.
Cushing disease; iatrogenic steroids long-term; muscle wasting
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A small number of animals with cushings disease end up with idiopathic cushings myotonia, which is...
when sustained, abnormal contraction of skeletal muscle leads to hypertrophy.
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What are characteristic clinical findings associated with cushings myotonia? (3)
characteristic gait, large muscles proximally, myotonic discharges on EMG
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How do you treat cushings myotonia? (2)
(if not inherited form) treat underlying cushings, give chloride channel inhibitors (procainamide, mexilitine)
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Hypokalemic myopathy in cats has a relatively _________ onset of... (4)
acute; weakness, muscle pain, ventroflexion of the neck, elevated CK.
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Hypokalemic myopathy in cats is very commonly associated with ____________.
chronic renal failure
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How do you treat hypokalemic myopathy in cats?
K+ supplementation
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Muscular dystrophy is a ___________ disease with a hallmark ____________.
congenital; severely elevated CK
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Muscular dystrophy may present with... (4)
progressive weakness, atrophy or hypertrophy of muscles, dysphagia, trouble breathing
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Muscular dystrophy is life-threatening when it causes _________.
congestive heart failure
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Muscular dystrophy is caused by...
X-linked (mostly males) mutation in dystrophin gene, leading to destabilization of muscle membranes
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