11 Neuropath Muscle and Nerve

Question 1

T-F– all muscle fibers in the motor unit are the same type and do not mix with other motor unit fibers?

Answer 1

False- same type per motor unit, but muscle fibers from diff. motor units can intermix with each other.

Question 2

T-F– all muscle fibers in the motor unit are the same type and do not mix with other motor unit fibers?

Answer 2

False- same type per motor unit, but muscle fibers from diff. motor units can intermix with each other.

Question 3

What are the 2 types of axonal degeneration?

Answer 3

1. Classic Wallerian degeneration

2. Distal axonopathy

Question 4

What are the 2 main causes of classic wallerian degeneration?

Answer 4

Trauma and vascular disease

Question 5

What causes distal axonopathy? 3

Answer 5

1. systemic metabolic disease
2. toxins
3. Some genetic diseases

Question 6

What are the two types of peripheral neuropathy?

Answer 6

axonal degeneration and demyelination

Question 7

Review the 4 main types of axonal degeneration- ischemic neuropathies?

Answer 7

1. Vasculitis
2. Collagen VascularDisease
3. Paraneoplastic Microvasculitis
4. Diabetic symmetrical sensorimotor neuropathy

Question 8

What are we looking for in vasculitis on microscopic imaging?

Answer 8

fibrinoid necrosis of vessel walls

Question 9

What is distinct about vasculitic neuropathy that we can see on microscopic imaging?

Answer 9

1. fascicle to fascicle variation in degree of axon loss

[in the image, the one with the most loss has less black looking axons)

Question 10

What is distinct about vasculitic neuropathy that we can see on microscopic imaging?

Answer 10

1. fascicle to fascicle variation in degree of axon loss

[in the image, the one with the most loss has less black looking axons)

Question 11

What type of neuropathy has both metabolic and toxic neuropathy?
is it predominantly axonal degeneration or demyelination?
What type of ischemic component do we see?

Answer 11

1. diabetic neuropathy\
2. axonal degeneration
3. vascular hyalinization- endoneurial microvasculature thickening

Question 12

What type of neuropathy has both metabolic and toxic neuropathy?
is it predominantly axonal degeneration or demyelination?
What type of ischemic component do we see?

Answer 12

1. diabetic neuropathy\
2. axonal degeneration
3. vascular hyalinization- endoneurial microvasculature thickening

Question 13

On microscopic view of diabetic neuropathy, what do we readily see?

Answer 13

Axonal loss (lack of black circular axons) and vascular thickening.

Question 14

On microscopic view of diabetic neuropathy, what do we readily see?

Answer 14

Axonal loss (lack of black circular axons) and vascular thickening.

Question 15

What neuropathy has a segmental pattern of injury? What is the etiology 3?

Answer 15

1. demyelinating neuropathy

2. Inflammatory (guillain-barre), Toxins, Genetics (Charcot-marie-tooth)

Question 16

The genetic disease charcot-marie-tooth disease causes what type of neuropathy?

Answer 16

demyelinating- segmental

Question 17

What 4 things are found in Guillain-barre syndrome clinical presentation?

Answer 17

1. Ascending Paralysis
2. Can involve respiratory muscles
3. slowed conduction
4. elevated CSF protein

Question 18

What 4 things are found in Guillain-barre syndrome clinical presentation?

Answer 18

1. Ascending Paralysis
2. Can involve respiratory muscles
3. slowed conduction
4. elevated CSF protein

Question 19

Is guillain barre a antibody mediated disease or T-cell mediated>

Answer 19

T-cell mediated with macrophages

[endoneurial and perineurial]

Question 20

T-F- demyelination of naked axons results in a thicker sheath?

Answer 20

Fasle- thinner and internal length changes

Question 21

T-F- demyelination of naked axons results in a thicker sheath?

Answer 21

Fasle- thinner and internal length changes

Question 22

Cross section microscopy of a segment of nerve undergoing demyelination will show what?

Answer 22

myelin debris surrounding a naked axon

Question 23

What is the most common hereditary peripheral neuropathy?

Answer 23

hereditary motor and sensory neuropathy type 1- charcot-marie-tooth disease

Question 24

What is the most common hereditary peripheral neuropathy? Where do we see muscular atrophy?

Answer 24

1. hereditary motor and sensory neuropathy type 1- charcot-marie-tooth disease
2. progressive atrophy of calves-weakness

Question 25

What disease has repetitive demyelination and remyelination?

Answer 25

hereditary motor and sensory neuropathy type 1- charcot-marie-tooth disease

Question 26

What disease has repetitive demyelination and remyelination?

Answer 26

hereditary motor and sensory neuropathy type 1- charcot-marie-tooth disease

Question 27

In charcot marie tooth, what do we see on microscopic pathology?

Answer 27

1. Thinly myelinated axons | 2. Hypertrophic "onion-bulb" neuropathy

Question 28

In charcot marie tooth, what do we see on microscopic pathology?

Answer 28

1. Thinly myelinated axons | 2. Hypertrophic "onion-bulb" neuropathy

Question 29

Chronic demyelination and demyelination results in what?

Answer 29

onion-bulbs- concentric rings of schwann cell processes.

Question 30

Chronic demyelination and demyelination results in what?

Answer 30

onion-bulbs- concentric rings of schwann cell processes.

Question 31

What muscle fiber type is for sustained force and weight bearing? What is the nadh and atpase content? are lipids or glycogen abundant? slow twitch or fast twitch? color?

Answer 31

1. Type 1 2. NADH dark, ATPase light 3. lipids are abundant 4. slow-twitch 5. red

Question 32

What muscle fiber type is for sustained force and weight bearing? What is the nadh and atpase content? are lipids or glycogen abundant? slow twitch or fast twitch? color?

Answer 32

1. Type 1 2. NADH dark, ATPase light 3. lipids are abundant 4. slow-twitch 5. red

Question 33

What muscle fiber type is for sudden movement? What is the nadh and atpase content? are lipids or glycogen abundant? slow twitch or fast twitch? color?

Answer 33

1. Type II 2. NADH light, ATPase dark 3. Glycogen are abundant 4. fast twitch 5. white

Question 34

What muscle fiber type is for sudden movement? What is the nadh and atpase content? are lipids or glycogen abundant? slow twitch or fast twitch? color?

Answer 34

1. Type II 2. NADH light, ATPase dark 3. Glycogen are abundant 4. fast twitch 5. white

Question 35

When we stain muscle fibers for ATPase…what type of fibers are dark?

Answer 35

Type II-- (remember that their overall color is white but they are ATPase dark and TYPE I are atpase light and appear whiter)

Question 36

When we stain muscle fibers for ATPase…what type of fibers are dark?

Answer 36

Type II-- (remember that their overall color is white but they are ATPase dark and TYPE I are atpase light and appear whiter)

Question 37

What are the two main classifications of muscle disease?

Answer 37

Neurogenic and myopathic

Question 38

What are the two main classifications of muscle disease?

Answer 38

1. Neurogenic [motor neuron disease, peripheral neuropathy, neuromuscular junction] 2. myopathic [dystrophy, inflammatory, metabolic, congenital]

Question 39

What are the two main classifications of muscle disease?

Answer 39

1. Neurogenic [motor neuron disease, peripheral neuropathy, neuromuscular junction] 2. myopathic [dystrophy, inflammatory, metabolic, congenital]

Question 40

In neurogenic muscle disease where is the site of weakness? is there pain? fasciculations? serum enzyme changes? EMG signs? nerve conduction?

Answer 40

1. distal 2. absent 3. present 4. normal 5. EMG fibrillation potentials 6. Variable conduction

Question 41

In myopathic muscle disease where is the site of weakness? is there pain? fasciculations? serum enzyme changes? EMG signs? nerve conduction?

Answer 41

1. proximal 2. variable 3. absent 4. elevated 5. EMG polyphasic potentials 6. normal

Question 42

In myopathic muscle disease where is the site of weakness? is there pain? fasciculations? serum enzyme changes? EMG signs? nerve conduction?

Answer 42

1. proximal 2. variable 3. absent 4. elevated 5. EMG polyphasic potentials 6. normal

Question 43

What is the difference in histological atrophy between neuropathy and myopathy?

Answer 43

in neuropathy the fibers are angular and in groups, while in myopathy the fibers are rounded and scattered.

Question 44

What is the difference in histological atrophy between neuropathy and myopathy?

Answer 44

in neuropathy the fibers are angular and in groups, while in myopathy the fibers are rounded and scattered.

Question 45

What type of muscle disease results in fiber type grouping

Answer 45

neuropathy- nerve loss is followed by regeneration leads to larger motor units and fiber type grouping

Question 46

Review the myopathic diseases-

Answer 46

Dystrophy= duchenne, Becker, limb-girdle, myotonic. Metabolic=mitoch. myopathy, inborn errors of metabolism, hormonal abnormalities, alcohol rhabdo Inflammatory= polymyosits, dermatomyositis, inclusion body myositis Congenital= centronuclear myopathy, nemaline myopathy, central core disease

Question 47

Review the myopathic diseases-

Answer 47

Dystrophy= duchenne, Becker, limb-girdle, myotonic. Metabolic=mitoch. myopathy, inborn errors of metabolism, hormonal abnormalities, alcohol rhabdo Inflammatory= polymyosits, dermatomyositis, inclusion body myositis Congenital= centronuclear myopathy, nemaline myopathy, central core disease

Question 48

Is duchenne's x linked?

Answer 48

YEs

Question 49

What does dystrophin do?

Answer 49

links cytoplasmic actin to the cytoskeleton

Question 50

What do we see histologically in muscular dystrophy early in the disease?

Answer 50

myocyte necrosis | with atrophy and hypertrophy

Question 51

What do we see histologically in muscular dystrophy early in the disease?

Answer 51

myocyte necrosis | with atrophy and hypertrophy

Question 52

What do we see histologically in muscular dystrophy late in the disease?

Answer 52

endomysial fibrosis and fatty replacement

Question 53

What do we see histologically in muscular dystrophy late in the disease?

Answer 53

endomysial fibrosis and fatty replacement

Question 54

What disease is autosomal dominant, trinucleotide, and has multiple internal nuclei and occasional ring fibers?

Answer 54

myotonic dystrophy

Question 55

What do we see histologically in polymyositis early in the disease?

Answer 55

inflammation and muscle fiber necrosis

Question 56

What do we see histologically in polymyosits later in the disease?

Answer 56

regenerating muscle, inflammation, and scarring fibrosis

Question 57

What do we see histologically in polymyosits later in the disease?

Answer 57

regenerating muscle, inflammation, and scarring fibrosis

Question 58

What disease is described as gradual onset, male predominance after age 50. proximal and distal weakness. Lymphocystic inflammation, angular and round atrophy, autophagic "rimmed" vacuoles?

Answer 58

inflammatory myopathy- inclusion body myositis

Question 59

What do the rimmed vacuoles look like on stain?

Answer 59

stain is blue overall, clear vacuoles with purple surrounding

Question 60

What do the rimmed vacuoles look like on stain?

Answer 60

stain is blue overall, clear vacuoles with purple surrounding

Question 61

pompe's deficiency is in what enzyme? McArdles disease?

Answer 61

1. lysosomal a1,4-glucosidase | 2. myophosphorylase

Question 62

What is highly indicative of mitochondrial myopathy?

Answer 62

ragged red fibers

Question 63

How many mitochondrial genes are there?

Answer 63

37 22 tRNA 2 ribosomal RNA 13 polypeptide subunits of respiratory chain

Question 64

How many mitochondrial genes are there?

Answer 64

37 22 tRNA 2 ribosomal RNA 13 polypeptide subunits of respiratory chain

Question 65

What are the ragged red fibers?

Answer 65

areas of mitochondrial proliferation with paracrystalline inclusions