N: Pns, Nmj, And Muscle Dz

Front 1

What are the 4 classifications of muscle dz?

Back 1

- neurogenic
- NMJ
- primary muscle dz
- myopathies associated with systemic dz

Front 2

With an ATPase pH 9.8 stain, do Type I fibers stain light or dark? Type II?

Back 2

light
dark

Front 3

In myopathic injury, what is seen re: light microscopy examination of fibers?

Neurogenic?

Back 3

random pattern of atrophic & hypertrophic fibers, both fiber types

group atrophy of type 1 and type 2.

Front 4

Selective type 2 atrophy of muscle fibers on light microscopy is evident of what?

Selective Type 1 atrophy?

Back 4

non-specific finding (disuse, corticosteroid therapy, polymyalgia rheumatica)

congenital myopathies and myotonic dystrophy.

Front 5

Endoymsial fibrosis is most commonly seen when the muscular degeneration is due to which etiology?

Back 5

myopathies; prominent feature of DMD and Becker

Front 6

The following characteristics are more associated with which etiology of pathologic muscle dz:
- Necrosis w/ myophagocytosis
- regeneration
- random variation in fiber size
- increased central nuclei
- endomysial fibrosis
- fatty infiltration
- fiber splitting
- vacuolar changes
- inclusions and accumulations

Back 6

myopathic

Front 7

The following characteristics are more associated with which etiology of pathologic muscle dz:
- Atrophic, angulated fibers
- Fiber type grouping
- Group atrophy of both fiber types
- Target fibers

Back 7

Neurogenic

Front 8

What are some general categories (5) of myopathies?

Back 8

dystrophies, inflammatory myopathies, metabolic caused myopathies, congenital myopathies, toxic and drug induced

Front 9

Lambert-Eaton myasthenic syndrome affects which part of the muscular/nerve system?

How about myasthenia gravis?

Back 9

NMJ

NMJ

Front 10

What are some examples of neurogenic causes of muscle dz?

Back 10

Dz of motor neurons
- spinal muscular atrophy
- amyotrophic lateral sclerosis
- charcot-marie-tooth dz

dz of peripheral nerves/nerve roots

dz of NMJ
- myasthenia gravis
- Lambert-Eaton myasthenic syndrome

Front 11

Which dz is characterized by an absence of dystrophin membrane protein due to an X-linked mutation in the gene for dystrophin?

Back 11

DMD

Front 12

What is the most common, most severe muscular dystrophy?

Back 12

DMD, only affects males b/c X-linked.

Front 13

21 month old boy presents with parents complaining of waddling gait, difficulty climbing stairs, and difficulty rising from the floor. Parents report that the child did not begin walking until ~18 months of age.

On PE, pseudohypertrophy of calf muscles is noted, as well as weakness/wasting of the proximal limb-girdle muscles that is worse in the lower limbs than the upper limbs.

What is your dx?

Back 13

DMD

Front 14

What is Gower's sign?

Back 14

this weird way pts with DMD get off the ground due to muscle weakness..... almost looks like they're someone who is just 100% exhausted.

Front 15

What is the prognosis for DMD?

Back 15

wheelchair bound by age 12, intellectual impairment
--> profound muscle weakness, respiratory, and cardiac issues
... death in mid teens to late twenties.

Front 16

What is Becker Muscular Dystrophy?

Back 16

milder form of DMD with later onset.

Front 17

What are two inflammatory myopathies characterized by symmertrical, proximal muscle weakness which is often painful?

Are they more common in M or F?

EMG change?

Back 17

Polymyositis/Dermatomyositis

2:1 male

myopathic EMG changes

Front 18

Characterize Polymyositis.

In which age group is it prevalent?

tx?

Back 18

30-60% of inflammatory myopathies

Autoimmune mediated disease secondary to defective cellular immunity
Adults, age 40-60
Tx: steroids

Front 19

Characterize Dermatomyositis.

In which age group is it prevalent?
-other associations?

tx?

Back 19

Antibody mediated injury to microvasculature
Adults and children
Characteristic skin rash
Gottron lesions
Association with malignancy
Tx: steroids

Front 20

Which inflammatory myopathy is characterized by Gottron's papules and telangiectasias?

Back 20

Dermatomyositis

Front 21

Which inflammatory myopathy is characterized by lymphocytes invading a myofiber... what is essentially endomysial chronic inflammation?

Back 21

Polymyositis

Front 22

Which inflammatory myopathy is characterized by perifascicular atrophy, and perivascular inflammation (mixed B- and T-cell )?

Back 22

Dermatomyositis

Front 23

A deletion in Survival Moton Neuron (SMN) gene on crsm5 leads to which dz?

Back 23

Spinal Muscular Atrophy (Werdnig-Hoffman dz)

Front 24

Baby is brought into the clinic with parents complaining that child cannot control it's head, and cannot sit upright. On exam, there is marked hypotonia "floppy baby", proximal>distal weakness; however, facial muscles are spared. CK is normal, but denervation changes are seen on EMG.

dx?
etiology?
prog?

finding on LM?

Back 24

Spinal Muscular atrophy (Werdnig-Hoffman dz)

Due to a degeneration/loss of anterior horn cells in the spinal cord
Deletion in the Survival Motor Neuron gene (SMN) on chromosome 5

Respiratory problems leading to pneumonia & death before age 2

- Large groups of atrophic, round fibers
- fascicular atrophy
- fiber type grouping
- Hypertrophy of type 1 fibers
- increased connective tissue

Front 25

Re: PNS neurons, what causes "onion bulbs" of schwann cells?

Back 25

recurring episodes of demyelination.

Front 26

What is the most common hereditary neuropathy?

Acquired neuropathy in USA? World?

Back 26

Charcot-Marie-Tooth (CMT) dz.

Diabetic neuropathy
Leprosy

Front 27

What is the most common subtype of peripheral neuropathy?

Back 27

axonal (so named b/c axonal degeneration predominates in these dz) - dying back-type.

--> "distal axonal neuropathy"

Front 28

How can nerve conduction velocity (electrophysiological studies) help to differentiate b/t axonal type and demyelination type?

Back 28

axonal = velocity near normal
demyelination type = velocity significantly decreased

Front 29

What are some clinical features of peripheral neuropathy?

Can these dz be selective for the types of fibers they affect (large myelinated vs small myelinated and unmyelinated)?

Back 29

muscle weakness, muscle atrophy, sensory loss, paresthesia, pain, and autonomic dysfunction

Yes (this would be PPTP vs PT, in the order given)

Front 30

Polyneuropathies often show what type of pattern, clinically?

Back 30

glove and stocking
"length-dependent neuropathy"

Front 31

Name some causes of axonal neuropathy.

Back 31

diabetes mellitus
alcoholism and nutritional
uremia
drugs/toxins
amyloidosis
systemic vasculitis
paraneoplastic syndx
infections
idiopathic.

Front 32

What is the most common form (type of manifestation) of diabetic neuropathy?
- subtype?

Back 32

distal, predominantly sensory polyneuropathy.
- can also be autonomic, sensorimotor, mononeuroplathic, etc. though

- distal axonal degeneration predominantes, but demyelination is present as well.

Front 33

How does alcoholic, uremic, and most drug related neuropathies present?
- subtype?

Back 33

distal sensorimotor polyneuropathy.
- distal axonal degeneration

Front 34

What is the definitive tx for uremic neuropathy?

Back 34

dialysis/renal txplt

Front 35

What typically causes vasculitis neuropathy in systemic vasculitis like with Churg-Strauss, Wegener's, polyarteritis nodosa, & microscopic polyangiitis? Is this also true of connective tissue dz (RA, SLE) and HIV infections?

Back 35

nerve ischemia --> axonal neuropathy.

Yes, these dz can cause vasculitic neuropathy.

Front 36

Amyloid neuropathy can be a complication of which of the following?
- light-chain AL found with primary systemic amyloidosis
- light chain AL found in MM
- secondary amyloidosis (AA)

How does this neuropathy often present (subtype)?

Back 36

both AL's.

small-fiber neuropathy

Front 37

What are the sorts (3) of immune-mediated demyelinateing neuropathies?

Back 37

- acute inflammatory demyleinating polyradiculoneuropathy (AIDP)
- CIDP
- anti-MAG IgM paraproteinemic demyelinating neuropathy

Front 38

What are 3 hereditary demyelinating neuropathies?

Back 38

- CMT1 subtype of CMT dz
- hereditary neuropathy w/ liability to pressure palsies (HNPP)
- Dejerine-Sottas syndrome

Front 39

What is the most common cause of Fuillain-Barre syndrome?

Pathogenesis?

Pathologic/Clincal features?

What does lumbar puncture typically show in Guillain-Barre syndx?

Back 39

AIDP
- often follows bacterial, viral, or mycoplasmal infections
- PNS shows multifocal areas of demyelination, remyelination, onion bulbs, and some axonal loss. Demyelination is often accentuated in more proximal nerves and roots

increase protein and *no* pleocytosis.

Front 40

Differentiate AIDP and CIDP.

Histological/clinical fx?

Back 40

Unlike AIDP, an antecedent upper respiratory or gastrointestinal infection is usually not reported in CIDP.
CIDP may occur sporadically or be associated with paraproteinemia, HIV infection, chronic active hepatitis, connective tissue disease, inflammatory bowel disease, or Hodgkin lymphoma.

The nerves and roots show a chronic demyelinating neuropathy accompanied by chronic inflammatory infiltrates. The nerves may show numerous onion bulbs, owing to the recurring episodes of demyelination.

Front 41

Fill in the chart, with special emphasis on CMT1, Dejerine Sotta, and HNPP.

Back 41

Front 42

72-yo man complains to his physicain of a 6m hx of progressive fatigue and leg cramps. he has also noticed twitching of the muscles on his chest (fasciculations) and difficulty lifting his left foot when he walks (foot drop). HE reports that on a few occasions he choked on food while swallowing. Cognitive fx appears normal, and the pt denies difficulty w/ bowel or bladder fx. PE shows bilateral diffuse muscle wasting in both upper and lower extremitites w/ prominent fasciculations in all muscle groups. Muscle tone is increased, and tendon reflexes are hyperreactive in all four extremities. Pt shows a positive Babinski's sign but sensory exam and coordination are normal. EMG shows denervation and fasciculations. What is the dx?

Characterize the general features of this dz.

Back 42

ALS
UMN & LMN sx
eye & sphincter usually spared, as are sensory sx.
There is typically no dementia or cerebellar or extrapyramidal dysfunction.

Front 43

Can the familial form of ALS be distinguished from the sporadic variant?
- is the familial form dom or recs?

Back 43

no.
- autosomal dominant.

Front 44

What gross anatomic changes are seen in ALS?

microscopic?

Back 44

degeneration or corticospinal or UMN and observable alterations of lateral pyramidal pathways of the spinal cord. Ventral roots atrophy secondary to loss of anterior horn LMNs. affected muscles are shrunken and pale.

loss of large motor neurons in the anterior horn of the spinal cord as well as the hypoglossal nucleus. This is accompanied by mild gliosis.
- neurofilaments aggregate in axons --> spheroids

Front 45

What might be causing the pathology of ALS? Thus, what might be helpful as a tx?

**not that important**

Back 45

muscles *might* be getting damaged by glutamate.

- riluzole (inhib glutamate release)
- mementine

Front 46

Describe the pathogenesis of myasthenia gravis.

What is often an effective tx?

Back 46

immunologic attack on the Ach receptor of the motor endplate. Antibodies attach to various receptor protein epitopes, thereby reducing the number of receptors.

thymectomy, in those pts with thymoma or hyperplasia of thymus.

corticosteroids, methotrexate, and anti AChesterase. Plasmapheresis can also help in the short-term to \plasma antibodies.

Front 47

What are common clinical sx of myasthenia gravis?

Back 47

- sx wax and wane
- weakness of extraocular muscles is typically severe and causes ptosis and siplopia.

Front 48

What is lambert-eaton syndrome?

What cancer is it often associated with?

Pathogenesis?

Tx?

Back 48

paraneoplastic disorder that manifests as muscular weakness, wasting, and fatigability of proximal limbs and trunk. Also termed myasthenic–myopathic syndrome

Small cell lung carcinoma

evidence for a defect in ACh release @ nerve terminals. This dz can be transferred to mice by IgG from human pts.
These pathogenic IgG target voltage sensitive Ca++ channels necessary for the release of ACh.

responds to corticosteroids.