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Pathology II > LEC 5, 6 - Skeletal Muscle I/II > Flashcards

LEC 5, 6 - Skeletal Muscle I/II Flashcards

1
Q

What are muscles made of? Describe.

A

Myofibers

Long, multinucleated cells

Little to no regenerative capacity

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2
Q

Describe: Type 1 muscle

A

Rich in mitochondria

High oxidative metabolism

Slow contracting/fatiguing

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3
Q

Describe: Type 2A

A

Mixed oxidative/glycolytic metabolism

Fast contracting

Slow fatiguing

Quick, short contractions

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4
Q

Describe: Type 2B

A

Glycolytic metabolism

Fast contracting/Fatiguing

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5
Q

Describe: Type 2c

A

Regernating fibers

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6
Q

Describe: Stellate cells

A

Run along length of myofibers

Full capacity of division + fusion

Restore - mature myofibers

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7
Q

What are the two classifications of changes in myofibers?

A

Neuropathic

Myopathic

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8
Q

What are neuropathic changes to myofibers?

A

Effect or absence of nerve supply

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9
Q

What are myopathic changes in myofibers?

A

Primary changes within muscle cells/fibers

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10
Q

What is involved in nueromusclar disease?

A

Lower motor neurons

Peripheral nerves

Neuromusclar junctions and muscles

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11
Q

What are clinicopathologic findings to suggest that there is damage to the muscle?

A

Creatine kinase elevation

AST + LDH elevation

Carbonic anhydrase III + FABP

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12
Q

Possible cause for pallor

A

Necrosis

Denervation

Anemia

Young animals

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13
Q

Possible cause for pale streaking

A

Necrosis

Mineralization

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14
Q

Possible cause for dark red mottling

A

Congestion

Hemorrhagic necrosis

Inflammation

Myoglobin staining

Hypostatic congstion

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15
Q

Possible cause for green color to muscles

A

Eosinophilic inflammation

Putrefaction

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16
Q

Possible cause for lipofuscin

A

Old animals

Especially cattle

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17
Q

Possible cause for black

A

melanosis

melanoma

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18
Q

Possible cause for thickened/firm muscle texture

A

Mineralization

Calcification

Fibrosis

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19
Q

Possible cause for soft texture to muscles

A

Fat infiltration or necrosis

Autolysis

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20
Q

How do you collect muscle samples?

A

Collect strip not larger than 1 cm

Myofibers running length wise

Place sample on rigid surface to avoid contraction band artifact

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21
Q

What are degenerative muscle disease?

A

Myopathies resulting in segmental or global necrosis in which inflammatory cells are not the cause of damage

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22
Q

What are the possible causes of degenerative muscle disease?

A

Ischemia

Nutritional deficiencies

Toxic myopathies

Extertional myopathies

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23
Q

What can cause ischemia that leads to degerneation of the muscle?

A

Occulusion of a major blood vessel

External pressure on a muscle

Swelling of a muscle in a nonexpendable compartment

Vasculitis

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24
Q

What is an example of ischemic necrosis in cattle?

A

Downer cow syndrome

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25
What animal most commonly sees muscle degeneration due to nutritional defiecencies?
Livestock
26
What nutritional deficiencies cause muscle degeneration?
Vitamin E Selenium
27
What is the function of selenium?
trace mineral vital of glutathione peroxidase system Protects from oxidative injurt
28
What disease does selenium deficiency cause?
White muscle disease
29
What are the three major toxins that cause muscle degeneration?
Ionophores Plants Pasture-associated myopathy
30
Who is affected by pasture-associated myopathy?
Horses
31
What are the ionophores that can cause muscle degeneration?
Monensin Narasin etc.
32
What are examples of plants that cause muscle degeneration?
Cassia occidentalis ## Footnote Gossypol
33
What predisposes an animal to exertional myopathies?
Vit E/Selenium deficency Muscular dystrophy Glycogen storage disease Severe electrolyte depletion
34
What are examples of extertional rhabdomyolysis?
Black-water Monday morning sickness
35
What are the three classes of congenital defects that lead to musclar degeneration?
Anatomic defects Muscular dystrophy Myotonia
36
Describe: Muscular dystrophy
Inherited, progressive, degenerative primary disease of myofibers Ongoing necrosis + regeneration
37
What is a disease of muscular dystrophy in cats and dogs? What is affected?
Duchennes's muscular dystrophy Dystrophin gene
38
Describe: Myotonia
aka Channelopathies Inability of myofibers to relax = spasmodic contractions Most due to abnormal ion channel formation
39
What are the three types of anatomical defects that lead to musclar degeneration?
Innervation Genetic Failure of normal development
40
What is an example of genetic defect in cattle and dogs that cuase muscular degeneration?
Double muscling aka congenital muscular hyperplasia
41
How does malignant hyperthermia occur?
Unregulated release of calcium from sarcoplasmic reticulum Leads to excessive contraction = heat Increased body temperature is the result
42
What animals are affected by malignant hyperthermia?
Dogs + Horses + Pigs
43
What is the defect in exactly that causes malignant hyperthermia?
Ryanodine receptor
44
What can trigger a maligant hyperthermia episode?
General anesthetic Stress - porcine stress syndrome
45
What characterizes a metabolic myopathy?
Reduced muscle cell energy production
46
Describe: Type II Glycogenoses
Acid maltase deficiency
47
Describe: Type IV glycogenoses
Glycogen branching enzyme deficiency
48
Describe: Type V glycogenoses
Myophosphorylase deficency
49
Describe: Type VII glycogenoses
Phosphofructokinase deficiency
50
What occurs with most endocrine myopathies?
Result in muscle atrophy Mostly in type 2 fibers
51
What happens in dogs with hypercortisolism?
Hypertrophy Pseudomyotonia
52
What electrolyte imbalances can cause muscle weakness?
Hypocalcemia Hypokalemia Hypophosphatemia Hypernatremia
53
Describe: Neuromuscular junction disorders
Impair the ability nerves impulses across the neuromuscular juncton
54
What are the three most common neuromuscular junction disorders?
Myastenia gravis Botulism Tick paralysis
55
What is the tick responsible for tick paralysis?
Dermacentor Ixodes
56
How does tick paralysis occur?
Toxin from tick block the release of acetylcholine from axon terminal
57
What animal is most commonly infected by tick paralysis?
Dogs
58
how is recovery initiated in regards to tick paralysis?
Removal of the tick Rapid 24 to 48 hours
59
What bacteria is responsible for botulism?
Clostridium botulism
60
Where is clostridium found?
GI tract soil
61
What is botulism characterized by?
Profound flaccid paralysis
62
What is the mechanism by which the botulism toxin causes paralysis?
Cleavage of proteins in charge of release of acetylcholine from presynaptic vesciles
63
What type of botulism toxin are dogs most sensitive to?
type C
64
What type of botulism toxin are cattle most sensitive to?
Type C + D
65
What type of botulism toxins are horses most sensitive to?
Type B + C
66
What animal is most sensitive to botulism overall?
Horses
67
How does the acquired form of myasthenia gravis occur?
Immune-mediated disorder caused via circulated autoantibodies against skeletal muscle acetylcholine receptor
68
What is the acquired form of myasthenia gravis associated with?
Thymic abnormalities Secondary loss of self-tolerance to acetylcholine receptors
69
How is the acquired form of myasthenia gravis diagnosed?
Detection of autoantibodies to acetylcholine receptors in the blood
70
How does the congenital form of myasthenia gravis occur?
Dogs and Cats Born with defective NMJ that decrease membrane surface area as a result of reduced actylcholine receptor density
71
What are the signs of myasthenia gravis?
Profound, sustained and progressive muscle weakness
72
What are the primary neoplasms of the muscle?
Rhabdomyoma/Rhabdomyosarcoma Peripheral nerve sheath tumors Fibromas/sarcomas Hemangiomas/sarcomas
73
What does rhabdomyoma/sarcoma arise from?
Intramuscular pluripotential cells Dogs + horses + Cats
74
Describe: Rhabdomyoma
Benign Smooth, nodular, pink, unencapsulated
75
Where are rhabdomyomas most commonly occur?
Larynx of adult dogs
76
Where are rhabdomyosarcomas most commonly found?
Neck Oral Cavity - Tongue
77
What do rhabdomyosarcomas look like grossly?
Grossly pink and fleshy, often have prominent local invasion Malignant
78
Where do hemangiosarcomas most commonly metastasize to?
Lungs
79
What animals are hemangiosarcomas most commonly found in?
Horses Dog
80
What is seen with clostridial myositis in horses?
Malignant edema Gas gangrene
81
What are the clostridium species that infect horses causing clostridial myositis?
Septicum Perfringens Chauvoei Novyi Fallax
82
How does clostridium infect the muscles of a horse?
Penetrating wounds Blood stream
83
What does clostridium do in anaerobic condition?
Bacteria proliferate Produce toxins Result in: Hemorrhage Edema Necrosis
84
What are the clinical signs of clostridial myositis?
Acute onset of heat, swelling and pain Fever, depression, anorexia, and dehydration Mild to Moderate increase in CK + AST
85
What does the muscle look like grossly when infected with clostridial myositis?
Swollen, edematous, and hemorrhagic Dark red to pale areas Suppurative exudate Gas bubbles
86
What are the clinical signs of botulism?
Flaccid paralysis Dysphagia Tongue + Eyelid weakness CK and AST are WNL
87
What is seen either grossly or histologically with botulism?
No findings Aspiration pneumonia can occur
88
What is used to diagnose animal with botulism?
Detection of toxin in stomach contents
89
What bateria is responsible for piegon fever?
Corynebacterium pseudotuberculosis
90
What are the clinical signs of piegon fever?
Multifocal intramusclar abscesses Pectoral muscle most commonly infected Common fever
91
What is seen grossly with pigeon fever?
Swelling + Edema Localized areas of suppurative exudate accumulation
92
What is the pathogenesis of pigeon fever?
Enter the body through wounds Bacterial exotoxin (phospholipase D) Leads to vascular damage + Inhibits neutrophil function
93
What are the two degenerative myopathies associated with streptococcus equi equi infections?
Purpura hemorrhagica Rhabdomyloysis + muscle atrophy
94
What is seen histologically with purpura hemorrhagica?
Leukocytoclastic vasculitis Fibrinoid necrosis of blood vessels
95
What is the gross appearance of purpura hemorrhagica?
Multiple muscles Disscecting hemorrhage + edema No gas bubbles
96
What are the clinical signs of purpura hemorrhagica?
Depression Fever Petechial +/- ecchymoses Anemia Myoglobinuria Very High CK + AST
97
What is the pathogenesis of purpura hemorrhagica?
Immune response to bacteria Immune complexes form (IgA + Antigen) Deposit in small blood vessels Vasculitis --\> vascular necrosis \> hemorrhage \> ischemia
98
What is the gross appearance of streptococcal-associated rhabdomyosis?
Decrease in muscle mass
99
What are the clinical signs of streptococcal-associated rhabdomyolysis + muscle atrophy?
Atrophy along paraspinal + gluteal muscles High elevations of CK + AST No purpura hemorrhagica seen
100
What is the pathogenesis of streptococcal-associated rhabdomyolysis?
Predisposed to immune-mediated damage caused by cross-reaction of streptococcal antibodies with muscle proteins
101
What animals are most likely to get streptococcal-associated rhabdomyolysis?
Young animals Quarter horses
102
What is the cause of protozoal myopathy?
Sarcocystis Most commonly Fayeri
103
What is seen histologically with protozoal myopahty?
Cysts within myofibers No inflammatory reaction generated
104
What is the pathogenesis of nutritional myopathy?
Lack of elements enhance oxidative injury of actively contracting muscle fibers
105
What is the gross appearance of nutritional myopathy?
Depends on stage of necrosis
106
What are the clinical signs of nutritional myopathy?
Weak suckling or impaired mastication Chronic = Bilateral symmetrical atrophy of masseter musccles Mild to moderate increase in CK + AST
107
What is the pathogenesis behind ionophore toxicity?
Results in calicum overload Leads to necrosis of skeletal + cardiac muscle cells
108
Describe: Hyperkalemic periodic paralysis
Myotonic disorder Autosomal dominant Point mutation in gene encoding for alpha unit of skeletal muscle sodium channel
109
What are the gross findings in HYPP?
None
110
What is seen histologically in HYPP cases?
Vacular degeneration of type 2 myofibers
111
What are the clinical signs of HYPP?
Transient muscle spasms Protrustion of third eyelid Gerenalized flaccid paralysis CK + AST normal
112
What is the pathogenesis of HYPP?
Delayed inactivation of sodium channel acitivity Leads to membrane instability + continous electrical activity
113
Describe: Equine polysaccharide storage myopathy
Autosomal dominant trait Point mutation in skeletal muscle glycogen synthase 1 gene (GYS1)
114
What horses are most affected by EPSSm?
Quarter horse Warm blood Arabian Morgan Pony of Americas
115
What are the clinical signs of EPSSM?
Stiff gait Symmetric muscle atrophy Back soreness Muscle cramping CK + AST normal
116
What is seen histologically with EPSSM?
Aggregates of intracytoplasmic material Stains postive with PAS reaction for glycogen
117
What is seen grossly with EPSSM?
Affected muscles are pale pink or diffusely red tinged
118
What is the pathogensis of EPSSM?
Accumulation of glycogen within myofibers Leads to insuffiecent energy prodcution + abnormal myofiber function
119
Describe: Glycogen brancher enzyme deficiency
Autosomal recessive Accumulation of unbranched chains of glycose occur wtihin the cell Leads to abnormal glycogen formation + intramyofiber deposits
120
What are the gross findings with GBE def?
None
121
What are the clinical signs of GBE def?
Foals may be aborted, stillborn, or weak Contracted tendons Rhabdomyosis or cardiac failure early in life
122
What is seen histologically with GBE def?
Hyaline inclusions within skeletal and cardiac muscle RESISTANT TO AMYLASE DIGESTION Positive stain with PAS
123
What is the cause of monday morning sicknees?
Unknown Associated with: Nutritional myopathy EPSSM Hypothyroidism
124
What is seen grossly with monday morning sickness?
Similar to EPSSM
125
What is seen histologically with monday morning sickness?
Localized widespread type 2 myofiber necrosis Macrophage infiltration/regeneration
126
What are the clinical signs of monday morning sickness?
Sudden onset of stiff gait Reluctance to move Swelling of muscle grousp CK + AST markedly elevated
127
What does ischemic myopathy affect?
Pectoral Abodominal Limb muscles
128
Describe: Postanesthetic myopathy
Occurs in horses Prolonged recumbency during general anesthesia
129
What are the four peripheral neuropathies in horses?
Sweeny Stringhalt Fibrotic myopathy Laryngeal hemiplagia
130
Describe: Sweeny
Unilateral scapular muscle atrophy Due to traunma or damage to suprascapular nerve Poorly fitted harness
131
Describe: Stringhalt
Sporadic pelvic limb neuropathy Exaggerated flexion of one or both limbs Unknown cause Possible: Hypochoeris plant
132
Describe: Fibrotic myopathy
Hamstring muscle trauma restriction of forward swing of affected limb
133
What nerve is affected in laryngeal hemiplagia?
Left recurrent laryngeal
134
What are possible causes of laryngeal hemiplagia?
Lead toxicity Direct trauma Extension of guttural pouch infection and/or tumors
135
What is a characteristic of laryngeal hemiplagia?
roaring nose
136
What are the two kinds of motor neuronopathies seen in horses?
Equine protozoal myeloencephalitis Equine motor neuron disease
137
What organism is responsible for EPM?
Sarcocystic neurona
138
How does EPM occur?
Denervation atrophy of fasical + gluteal muscles
139
What causes equine motor neuron disease?
Prolonged vit E deficiency
140
What are the clinical signs of equine motor neuron disease?
Rapid muscle wasting Weakness Trembling Recumbency
141
What is seen grossly in a horse with equine motor neuron disesae?
Muscles turn yello-tan Gelatinous textures
142
What bacteria is responsible for black leg in cattle?
Clostridial myositis
143
What is the pathogenesis of blackleg?
Spores remain dormate in muscle Trauma occurs Hypoxia/anoia leads to spore activation Bacterial production of toxins Capillary wall damage Hemorrhage + Edema + Necrosis
144
What are the pyogenic bacteria that affect cattle?
Trueperella pyogenes Actinobacillus lignieresii Actinomyces bovis
145
What does actinomyces bovis cause in cattle?
Lumpy jaw
146
What is the pathogenesis of lumpy jaw?
Bacteria infects bone of jaw Chronic granulomatous to pyogranulomatous/fibrosing osteomyelitis
147
What does actinobacillus lignieresii cause in cattle?
Wooden tongue
148
What are the clinical signs of wooden tongue in cattle?
Excessive salivation due to difficulty swallowing
149
What are the gross findings with wooden tongue?
Rigid and swollen tongue
150
What is seen histologically with wooden tongue?
Mark fibrosis Multiple areas of pyo/granulomatous inflammation Contains eosinophilci material
151
What is the pathogenesis of wooden tongue?
Severe granulomatous to pyogranulomatous Fibrosis myositisi glossitis
152
What are the gross findings in cattle infected with trueperella pyogenes?
Single or multiple Abscesses and/or cellulitis Thick, yellow-green, foul smelling pus
153
What are the protozoal myopathies in cattle?
Sarcosytis Eosinphilic myositisi Neospora caninum
154
What occurs with neospora caninum infections in cattle?
No clinical disease in cattle Can infect fetus leading to abortion
155
Describe: Eosinophilic myositis
Sarcocystis infection Involved in hypersensitivity Green discoloration of muscle due to massive infiltration of EOS Necrosis and fibrosis occur
156
What muscles are most affected by nutritional myopathy in cattle?
Postural + Locomotion
157
How is nutritional myopathy diagnosed in cattle?
Blood levels of vit e. and selenium
158
What plant most commonly causes degenerative myopathy in cattle?
Cassia occidentalis aka coffee weed
159
What does coffee weed cause in cattle?
Necrosis Minimal to no mineralization
160
What are the clinical signs of ionophore toxicity?
Diarrhea Anorexia Generalized weakness CK + AST exteremely high
161
What is the cause of steatosis in cattle?
Defective in-utero muscle development Replacement of adiopocytes
162
What is seen histologically in cattle with steatosis?
Replacement of myofibers by adiopocytes Sudan black stain
163
Describe: Congenital muscular hyperplasia
Defect in myostatin gene
164
Animal affected: Multisystemic necrotizing vasculopathy
young Gelbvieh cattle
165
Animal affected: Motor neuron degenerative disease
Brown Swiss cattle
166
What are the causes of hypokalemic myopathy in cattle?
Anorexia Ketosis Glucocorticoids iwth high mineralcorticoid activity Activation of glucose transport w/ IV administration
167
What are the clinical signs of hypokalemic myopath?
Weakness Recumbency CK + AST moderatly elevated
168
What are the gross findings in hypokalemic myopathy?
None specific Necrosis of strenal muscles
169
What are the bacterial/protozoal myopathies in small ruminants and camelids?
Clostridial myositis Botulism Protozoal myopathy
170
What plant causes toxic myopathy in goats?
Porsopis glandulosa - honey mesquite
171
What does honey mesquite do to goats?
Degeneration of motor nucleus of the trigeminal nerve Denervation of masticatory muscles Progressive emaciation due to inability to eat
172
What are the clinical signs of myotonia in goats?
Severe muscle spasms characterized by stiffness Adoption of sawhorse stance CK + AST normal
173
What is since histologically in goats with myotonia?
Moderate myofiber hypertrophy
174
What is the cause of myotonia in goats?
Genetic defect of skeletal muscle chloride channel Decreased chloride conductance Ionic instability of sarcolemma
175
Describe: Megaesophagus in camelids
Tunica muscularis contains skeletal muscle Abnormal motility + dilation occur in adults Unknown cuase
176
What are the causes of bacterial myopathies in pigs?
Clostridium septicum T. pyogenes Trichinosis
177
What does T. pyogenes cause in pigs?
Pyogenic Muscular abscesses + cellulitis
178
What is the cause of trichinosis in pigs?
Trichinella ssp.
179
What are the gross findings in pigs with a trichinosis infection?
Small white nodules in muscle
180
What is seen histologically in pigs with a trichinosis infection?
Mixed inflammatory infiltrate inducing EOS
181
What is the pathogensis of trichinosis of pigs?
Adult nematode lives in SI Larvae penetrate mucosa + reach bloodstream Larvae encyst in myofibers Active muscle preferentially affected
182
What is plant affects pigs? How?
Cassia occidentalis Diaphragm
183
How does ionophore toxicity affect pigs?
Atria of the heart
184
What does gossypol cause in pigs?
Skeletal + Cardiac muscle necrosis Liver + Lungs lesions
185
Describe: Myofibrillar hypoplasia
aka Splay leg Abduction of limbs laterally Progressive flattension of the sternum Young piglets
186
What pigs are most commonly affected by Porcine stress syndrome?
Pigs with unpigmented hair coats
187
What is the cause of porcine stress syndrome?
Genetic defect in ryanodine receptor
188
What are the clinical signs of porcine stress syndrome?
Dramatically increased body temperature Severe muscle rigidity CK + AST markedly elevated
189
What gross findings are seen with porcine stress syndrome?
Muscles are pale, moist, swollen, and appear cooked Shoulder, back, and thigh most affected
190
What is seen histologically with porcine stress syndrome?
Myofibers Hypercontracted or Coagulative necrosis
191
What is the pathogenesis of porcine stress syndrome?
Ryanodine receptor = Calcium release channel in SR Uncontrolled intracytoplasimic Ca Release Excessive contraction Heat production
192
What causes protozoal myopathy in dogs?
Neospora caninum
193
What are clinical signs of neospora infection in a dog?
Progressive weakness Marked muscle atrophy CK + AST slightly increased
194
What is seen grossly in dogs infected with neospora?
Atrophied, pale and firm muscles
195
What is seen histologically in dogs with a neospora infection?
Myofiber necrosis Lymphoplasmacyctic inflammatory infiltrate Intracytoplasmic protozoal cysts
196
What is the pathogenesis of neospora infection in dogs?
Transmitted in utero Invade peripheral nervous system + skeletal muscle Affects ventral spinal roots = denervation of muscles
197
What are the clinical signs of Duchenne's type?
progressive weakness death Less severe: stiff short strife gait and excercise
198
What is the cause of Duchenne's type in dogs?
Dystropin gene affected Codes for membrane associated cytoskeletal protein Repeated bouts of myofiber necrosis + regeneration
199
What causes death in Duchenne's type?
Respiratory failure related to severe diaphragmatic necrosis
200
What is seen histologically with Duchenne's type?
Necrosis Mineralization Progressive dissecting fibrosis
201
What are the clinical signs of Lab. retriever centronuclear myopathy?
Neuromuscular weakness first 6 months Excercise intolerance Loss of patellar + triceps reflex CK + AST normal
202
What are the gross findings seen with centronuclear myopathy?
Poor muscling Possible megaesophagus
203
What is seen histologically with centronuclear myopathy?
Clusters of atrophic myofibers Myofiber hypertrophy Nuclei internalization
204
What breeds of dogs are affected by congenital myotonia?
Chow chow Miniature schnauzer Staffordshire terrier
205
What are the gross and histological findings of congenital myotonia in dogs?
Marked musclar hypertrophy
206
What are the clincal signs of congenital myotonia in dogs?
Movement with splayed, stiff thoracic limbs Bunny hop gait in pelvic limbs
207
What is the cause of congenital myotonia?
Decreased chloride conduction
208
What are the endocrine myopathies seen in dogs?
Hypothyroidism Hypercortisolism
209
What are the clinical signs of hypothyroidism?
Weakness Muscle atrophy Laryngeal paralysis Megaesophagus
210
What are the gross findings in a dog with hypothyroidism?
Overall muscle atrophy Thyroid gland bilateral atrophy Megaesophagus
211
What is seen histologically in a dog with hypothyroid ism?
Atrophy of type 2 myofibers Axonal degeneration
212
What causes hypercortisolism in dogs?
Increased adrenocortical cortisol production Exogenous corticosteroids
213
What are the clinical signs of hypercortisolism in dogs?
neuromuscular weakness CK + AST normal Cushingoid pseudomyotonia
214
Define: Cushingoid pseudomyotonia
Remarkabley stiff, stilted pelvic gait Increased muscle tone of proximal thigh muscles
215
What are the gross + histological findings in a dog with hypercortisolism?
Sysmmetric muscle atrophy Alopecia Bilateral cortical atrophy
216
What causes polymyositis in dogs?
Antibodies directed to skeletal muscles only
217
What are the gross findings in dogs with polymysitis?
Muscle throughout body can be affected Atrophy of temporal + masseter muscles Esophageal muscle involvement = megaesophagus
218
What is seen histologically in acute cases of polymuositisi?
Lymphocytic myosistisi Variable degree myofiber necrosis
219
What is seen histologically in chronic cases of polymyositis?
Regeneration Fibrosis
220
What causes masticatory myositis?
Antibodies against myosin isoform present in type 2 myofibers in dogs
221
What are the clincal/gross findings in a dog with masticatory myositisis?
Bilateral symmetric swelling of temporalis and masseter muscles Inability of full opening of the jaw
222
What is histological appearance of masticatory myosistis in dogs?
Lymphocytic myosistis (B-lymphocytes) Numerous eosinophils Necrosis Regeneration of myfibers
223
What dogs seem to get extraocular muscle myositis?
\< 2 years old Golden retrivers
224
How does extraocular muscle myositis present?
Actue onset of bilateral exopthalmos
225
What are the gross findings seen with extraocular muscle myosistis?
Extraocular muscles are swollen + pale yellow
226
What is seen histologically with extraocular muscle myosistis?
Myofiber necrosis Regeneration + Lymphocytic inflammation of muscles
227
What are the three disorders seen in dogs of the NMJ?
Myasthenia gravis Tick paralysis Botulism
228
What dogs are predisposed to myasthenia gravis?
Jack russels Smooth fox terriers Springer spaniels
229
What breeds of dogs are predisposed to exertional rhabdomyolysis?
Racing greyhounds Sled dogs
230
What muscles are most affected in dogs with exterional rhabdomyolysis?
Back + Thigh muscles
231
What breeds of dogs are predisposed to Motor neuron disease?
Brittany Spaniel Rottweiler
232
What is elevated in a cat with duchenne's type?
CK + AST + ALT
233
How does x-linked musclar dystrophy present in a cat?
Progressive, presistent stiff gait Associated with marked muscular atrophy
234
What does FeLV cause in cats muscularly?
Immune mediated myositis

Pathology II (20 decks)

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