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Pathology II > Lecture 19: Skeletal Muscle Pathology II > Flashcards

Lecture 19: Skeletal Muscle Pathology II Flashcards

1
Q

What is the cause of clostridial myositis in horses

A

C. Septicum

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2
Q

what is pathogenesis of clostridial myositis in horses

A

Clostridium so gain access to muscle by penetrating wounds or blood—-> anaerobic conditions—> bacteria proliferation and produce toxins that damage vessels—> hemorrhage, edema and necrosis

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3
Q

what are some clinical signs of clostridial myositis in horses

A

acute onset heat, swelling and pain within muscle groups

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4
Q

t or f: CK and AST are elevated in clostridial myositis

A

true

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5
Q

what is gross appearance of clostridial myositis

A

swollen, edematous, hemorrhagic muscles, suppurative pus, gas bubbles

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6
Q

how do you dx clostridial myositis

A

history, gross appearance, cytology, anaerobic cultures, FAB

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7
Q

necropsy and histopath of horse who presented with fever, pain, swelling of muscles, fever. Based on these findings what is dx and why

A

Muscle hemorrhage
Histo: gas bubbles, hemorrhage, inflammatory cells

Dx: clostridial myositis

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8
Q

what is cause of botulism

A

clostridial botulinum

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9
Q

what is pathogenesis of botulism

A

toxin causes cleavage of SNARE proteins responsible for ACh release from presynaptic vesicles resulting in flaccid paralysis

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10
Q

what are some clinical signs of botulism

A

flaccid paralysis, dysphasia, tongue and eyelid weakness

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11
Q

t or f: CK and AST limits are elevated with botulism

A

false

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12
Q

what are some gross findings of botulism

A

no specific findings, aspiration pneumonia may develop secondary to dysphagia

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13
Q

how do you dx botulism

A

clinical signs, detect toxin in stomach contents or contaminated feed

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14
Q

What wrong and what cause

A

Abscess in pectoral region
Cause: corynebacterium Pseudotuberculosis (pigeon fever)

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15
Q

what is pathogenesis of pigeon fever

A

C. Pseudotuberculosis in soil enters via penetrating wounds including injections—> bacterial exotoxins such as phospholipase D cause vascular damage and inhibit neutrophil function

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16
Q

How do you dx pigeon fever

A

cytology or culture of wounds

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17
Q

streptococcal associated myopathies in horses are associated with infection or exposure to __

A

S. Equi equi

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18
Q

purpura hemorrhagic is what type of hypersensitivity rxn

A

type 3

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19
Q

what is pathogenesis of purpura hemorrhagica

A

muscle damage caused by immune response to bacteria (not directly infecting muscle)—> immune complexes formed by IgA and streptococcal M protein—> deposit in small vessels—> vasculitis—> vascular wall necrosis—> hemorrhage—> ischemia, necrosis and infarction of myofibers

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20
Q

What likely cause of these lesions

A

Purpura hemorrhagica due to infection with S. Equi equi

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21
Q

what is histopath appearance for purpura hemorrhagic

A

leukocytoclastic vasculitis and fibrinoid necrosis of Blood vessels

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22
Q

horse presented with widespread hemorrhage/ecchymoses. Following histopath taken- what wrong

A

Necrosis of vessels
Cause: purpura hemorrhagic

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23
Q

what is streptococcal associated rhabdomyolysis and muscle atrophy

A

syndrome of severe acute rhabdomyolysis resulting in profound generalized loss of muscle

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24
Q

who is most frequently affected by streptococcal-associated rhabdomyolysis

A

young animals, quarter horses

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25
what is pathogenesis of streptococcal associated rhabdomyolysis and muscle atropgy
immune mediated muscle damage caused by cross reaction of streptococcal antibodies with muscle proteins (unregulated MHC I and II)
26
what are some clinical signs of streptococcal associated rhabdomyolysis and muscle atropgy
muscle atrophy most evident in paraspinal and gluteal muscles, elevated CK and AST
27
what wrong and what cause
muscle atrophy of gluteal muscles Histopatho: myonecrosis and macrophage infiltration Cause: streptococcal associated rhabdomyolysis and muscle atropgy
28
horse presented with extreme muscle atrophy over gluteal region- biopsy performed and IHC done- what does this indicate
brown= positive, upregulation of MHC I and II Cause: streptococcal associated rhabdomyolysis and muscle atropgy
29
From horse- what wrong/cause
protozoal myopathy- Sarcocystis spp
30
what Protozoa is suspected of causing degenerative myopathy with massive infection in horses
sarcocystis fayeri
31
what is cause of nutritional myopathy
vitamin E and/or selenium deficiency
32
what is pathogenesis of nutritional deficiency
lack of vitamin E and/or selenium enhance oxidative injury due to lack of antioxidant activity
33
what are some signs of nutritional myopathy in foals
weak suckling and/or impaired mastication and dysphagia. Bilateral symmetric atrophy of masseter muscles
34
what is pathogenesis of ionophore toxicity
overdose—> disrupted of ionic equilibrium—> ca2+ overload—> skeletal and cardiac muscle necrosis
35
what is equine polysaccharide storage myopathy and who is it most common in
autosomal dominant tract recognized in QH, warm blood, Arabian, Morgan, pony and draft breeds
36
what is cause of equine polysaccharide storage myopathy
point mutation in skeletal muscle glycogen synthase 1 (GYS1) gene
37
what is pathogenesis of equine polysaccharide storage myopathy
abnormal accumulation of glycogen in myofibers resulting in insufficient energy production and abnormal myofibers function
38
what are some clinical signs of equine polysaccharide storage myopathy
stiff gait, symmetric muscle atrophy, back soreness, muscle cramping, pelvic limb or generalized weakness
39
horse presents with stiff gait, muscle atrophy and muscle cramping. Following histo was taken. What wrong, what stain is this
aggregates of intracytoplasmic PAS positive glycogen stain: PAS
40
what is glycogen branching enzyme deficiency and who common in
autosomal recessive trait that affects QH and paints
41
what is pathogenesis of glycogen branching enzyme deficiency
defiance of GBE enzyme causes accumulation of unbranched chains of glucose which leads to abnormal glycogen formation and intramyofiber deposits
42
what are some signs of GBE deficiency
foals may be aborted, still birth, weak at birth, contracted tendons, rhabdomyolysis, cardiac failure
43
What are histo findings associated with GBE deficiency
hyaline inclusions in skeletal and cardiac muscle as well as Purkinje fibers and hepatocytes
44
what are some signs of equine exertional rhabdomyolysis
sudden onset stiff gait, reluctance to move, swelling of muscle groups, pain Elevated CK and AST
45
what is cause of equine exertional rhabdomyolysis
high grain and lack of exercise
46
what is histopath of equine exertional rhabdomyolysis look like
type 2 myofiber necrosis followed by macrophage infiltration and regeneration
47
what is ischemic myopathy
seen in recumbent animals affecting pectoral, abdominal and limbs muscles as a result of pressure interfering with vascular perfusion
48
what is postanesthetic myopathy
degenerative myopathy that can occur in horses undergoing prolonged recumbency during anesthesia
49
what is a common endocrine myopathy
pituitary hyperfunction (adenoma or hyperplasia) causing Cushing leading to muscle atrophy (preferentially of type 2 fibers) and weakness
50
what is peripheral neuropathy
injury to motor neurons results in muscle atrophy and dysfunction
51
what wrong and what cause
Sweeney- unilateral scapular muscle atrophy due to trauma or damage to suprascapular nerve in draft horses due to poorly fitted harness collar
52
what wrong and what cause
stringhalt- sporadic pelvic limb neuropathy characterized by exaggerated flexion of one or both pelvic limbs Cause: ingestion of hypochoeris radicata
53
what is a motor neuropathy
damage on motor neuron in nuclei of brainstem or ventral horns of spinal cord will result in Wallerian degeneration of peripheral nerves
54
what is cause and result of equine protozoal myeloencehalitis
cause: S. Neurona, Neospora spp Causes denervation atrophy usually to facial and gluteal muscles because of preferential damage to cranial nerve nuclei in brainstem or motor neurons of lumbosacral intumescence
55
older horse presented with generalized weakness. Based on appearance of muscle what is likely cause
muscle is yellow-tan and gelatinous Cause: equine motor neuron disease caused by prolonged vitamin E deficiency leads to motor neuron degeneration
56
how do horses with equine motor neuron disease present
rapid muscle wasting weakness, trembling and recumbent
57
what is cause of clostridial myositis (blackleg) in cattle
C. Chauvoei
58
what is pathogenesis of clostridial myositis in cattle
ingestion of organism—> crossing intestinal mucosa—> entering blood—> spores remain dormant in muscle—>trauma—>hypoxia—> sporadic activation and bacterial proliferation—> produce toxins—> capillary wall damage—> hemorrhage, edema, necrosis
59
from cow- what could;ve caused these hemorrhages and gas bubbles
C. Chauveoi- clostridial myositis
60
Abscesses all over cow, poke one and thick, yellow green foul smelling pus comes out. What is likely cause
T. Pyogenes
61
Cow tongue- what cause and pathogenesis
Wooden tongue: actinobacillus ligneiresi Oral wound or penetrating plant results in granulomatous to pyogranulomatous and fibrosing myositis/glossits
62
what likely cause and pathogenesis
Lumpy jaw: actinomyces bovis Infects jaw causing chronic granulomatous to pyogranulomatous and fibrosing osteomyelitis
63
what wrong and cause
eosinophilic myositis Cause: sarcocystis Green discoloration due to massive infiltration of eosinophils
64
what does neospora caninum cause in cattle
adults no disease, fetus can cause abortion- non-suppurative myositis, myocarditis and encephalitis
65
vitamin E and/or selenium deficiencies in cattle affect what muscles most commonly
locomotive and postural muscles
66
what is the mot common cause of degenerative myopathy in cattle
senna occidentalis (plant toxicity)
67
what is the cause of steatosis (lipomatosis) in cattle
defective in utero development of muscle, replaced by adipocytes
68
what stains can highlight fat and useful in steatosis dx
oil-red-o stain or Sudan black
69
cow presented with poor muscle developed- biopsy taken. What does histopath show and what stain
Steatosis/lipomatosis Stain: oil-red-o stain highlights adipocytes
70
what does the plant prosopis glandulosa (honey mesquite) cause in goats
degeneration of motor nucleus of trigeminal nerve in goats resulting in denervation atrophy of masticatory muscles with progressive emaciation
71
what is cause of mytonia in goats
inherited autosomal dominant trait causing genetic defect in skeletal muscle Cl- channel resulting in decreased cl- conduction ans assocaited ionic stability of sarcolemma
72
what are some signs of myotonia in goats
severe muscle spasms characterized by stiffness for 5-20 seconds, seahorse stain “fainting goat”
73
what wrong and cause
malignant edema Cause: C. Septicum mainly at sites of infection
74
From pig- what cause and pathogenesis
cause. Trichinella spiralis Pathogenesis: adult nematode lives in SI mucosa—> larvae penetrate mucosa and read blood—> larvae encyst in myofibers
75
in pigs cassia occidentalis affects __preferentially
diaphragm
76
in pigs ionophore toxicity affects __
Atria of heart
77
what goes gossypol (cottonseed products) cause in pigs
skeletal and cardiac muscle necrosis as well as liver and lung lesions
78
what wrong and cause
myofibrillar hypoplasia (splay leg) Affects young piglets resulting in abduction of limbs Delayed myofibrial development
79
What does neospora caninum cause in dogs
transmitted in utero and invades peripheral nervous system and skeletal muscle including heart. Preferentially affects ventral spinal roots causing denervation atrophy of muscles
80
what are some clinical signs of neospora caninum in dogs
progressive weakness, most profound in pelvic limbs, marked muscle atropgy
81
what is cause of X-linked muscular dystrophy (Duchenne’s type_
Defect In dystrophin gene which codes for membrane associated cytosketal protein
82
absence of dystrophin leaves skeletal muscle fiber susceptible to repeated __ and __
necrosis and regeneration
83
what are some clinical signs of X-linked muscular dystrophy
progressive weakness and death (death from respiratory failure), joint contracture and splaying of distal limbs
84
dog presents with progressive weakness and splaying of distal limbs, suspect X-linked muscular dystrophy- perform IHC- which one is normal and which abnormal- how do you know
Top normal: brown= + for dystrophin Bottom: dystrophin defect- not brown- no dystrophin
85
lab presents with muscle weakness, absent patellar and tricep reflexes and megaesophagus. Muscle biopsy taken. Which normal vs abnormal and what wrong
Labrador retriever centronuclear myopathy Left: abnormal, clusters of atrophic myofibers, myofiber hypertrophy and nuclei internalization Right: normal
86
what is cause of polymyositis
antibodies that can be directed to skeletal muscle—> myofiber necrosis
87
what are some gross findings of polymositis
atrophy of temporal and masseter muscles, megaesophagus
88
what is histopath for acute polymyositis in dogs
lymphocytic myositis (CD8+ T-lymphocyte rich)
89
what is histopath for chronic polymyositis
regeneration and fibrosis
90
dog presents with atrophy of temporal and masseter muscles- following biopsy taken what wrong
polymyositis Left: acute- lymphoplasmacytic myositis (CD8+ T-lymphocyte rich) Right: chronic
91
what is cause of masticatory myositis
antibodies against myosin isomorphic present in type 2 myofibers, type 2M myosin
92
what are some signs of acute masticatory myositis
bilateral symmetric swelling of temporal and masseter muscles, inability to fully open mouth
93
what are some signs of chronic masticatory myositis
atrophy of temporal and masseter muscles
94
what does histopath of masticatory myositis look like
lymphocytic myositis (B lymphocyte rich) and numerous eosinophils
95
dog presents with temporal and masseter atrophy, following histo path taken. What wrong and what histo show
Masticatory myositis Histo: lots of eosinophils
96
what does X-linked muscular dystrophy cause in cats
persistent stiff gait associated with marked by muscular hypertrophy
97
what disease in cats has been associated with immune mediated myositis and what histo is characteristic
FIV Histo: lymphocytic inflammation (Cd8+ T-lymphocyte rich)

Pathology II (26 decks)

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