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Med School Year 2 Flash Cards > Peripheral Nerve Disease > Flashcards

Peripheral Nerve Disease Flashcards

1
Q

What is segmental demyelination?

A

Damage to the myelin or Schwann cell disease

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2
Q

What is the process of recovery after demyelination?

A
  1. Disintegrating myelin is engulfed by Schwann cells, then by macrophages
  2. Axon stimulates endoneurium for remyelination
  3. New myelinated internodes are shorter and thinner
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3
Q

What are onion bulbs?

A

Concentric lays of Schwann cell cytoplasm and BM from sequential demyelination
Will eventually cause axonal injury

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4
Q

What is Guillan-barre?

A

Inflammation and demyelination of the peripheral nerves and spinal nerve roots

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5
Q

What are the sx of Guillan-Barre?

A

Decreased DTRs
Ascending paralysis
Increase CSF protein

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6
Q

What is the histo of Guillan-Barre?

A

Inflammation of nerves
Macrophage processes penetrate the BM of Schwann cells
Segmental demyelination

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7
Q

What is Guillan-Barre preceded by?

A

An acute flulike illness
Pathogens associated: campylobacter, CMV, EBV, mycoplasma
Mediated by T cells

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8
Q

What is seen in chronic inflammatory demyelinating polyradiculoneuropathy?

A

Symmetric sensorimotor polyneuropathy
Onion bulbs

Tx : steroids, plasmapheresis

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9
Q

What is seen in lepromatous infectious peripheral nerve disease?

A

M. Leprae invades the Schwann cells causing demyelination
Endoneurium fibrosis
Thickening of peri neural sheaths
Symmetric polyneuropathy — ulcers, wounds
Granulomatous inflammation of the dermis

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10
Q

What is seen in diphtheria?

A

Paresthesias
Weakness
Loss of proprioception and vibratory sense
Demyelination of axons in the anterior and posterior roots

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11
Q

What is Walllerian degeneration?

A

Degeneration of distal ends of fibers on a focally damaged axon

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12
Q

What is denervation atrophy?

A

When muscle fibers lose neural input

Will see angulated cells and target fibers (rounded zone of reorganization)

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13
Q

What is the cause of axonal degeneration and muscle fib atrophy?

A

Trauma

Ischemia

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14
Q

What happens in reinnervation?

A

Neighboring unaffected motor unit sprouts over to innovate the damaged segment— loss of checkerboard, get type grouping

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15
Q

What is the inheritance pattern of muscular dystrophy?

A

X linked

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16
Q

What is the mutation in muscular dystrophy?

A

Frameshift or point mutation in X that codes for dystrophin

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17
Q

What is dystrophin?

A

Cytoplasmic protein of z band that forms the interface between intracellular contractile apparatus and extra cellular connective tissue matrix

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18
Q

What is the histo of muscular dystrophy?

A

Variation in fiber size,
Muscle replaces by fat and CT
Hyper contracted fibers

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19
Q

What are hyper contracted fibers?

A

Enlarged, rounded, hyaline fiber with no cross striation in DMD

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20
Q

What do females who are carriers of DMD often have?

A

Dilated cardiomyopathy

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21
Q

What are the sx of DMD?

A

Delay in walking
Pseudo hypertrophy of calf muscles - increase in fat and CT tissue
Cardiac arrhythmias
Cognitive impairment

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22
Q

What are the causes of death in DMD?

A

Respiratory insufficiency
Cardiac decomp
Pulmonary infection

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23
Q

What is dystrophy is autosomal dominant in inheritance and autosomal recessive?

A

Limb girdle

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24
Q

What is the mutation in limb girdle dystrophy?

A

In sacroglycan complex which interacts with dystrophin via b-dystroglophin

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25
What is the inheritance pattern of myotonic dystrophy?
Auto Dom
26
What is the mutation in myotonic dystrophy?
CTG repeat on ch.19 that affects DMPK
27
What dystrophy has ring fibers, change in intrafusal fibers, sarcoplasmic mass
Myotonic
28
What are the sx of myotonic dystrophy?
``` Abnormal gait Ptosis Cataracts Frontal balding Gonadal atrophy Dementia Decrease IgG Sustained involuntary contraction ```
29
What myopathy is due to vigorous exercise, cold, or high carb meals?
Ion channel myopathies
30
Which gene is mutated in the hypokalemic kind?
Gene for voltage gated calcium channel
31
What gene is mutated in the hyperkalemic ion channel myopathy?
Sodium channel in skeletal muscle
32
What is malignant hyperprexia?
Hyper metabolic state induced by halogenated anesthesias
33
What is abnormal in the lipid myopathies?
Carnitine transport system | Deficiency of mitochondrial dehydrogenase enzyme
34
What do you see in lipid myopathies?
Accumulation of lipid droplets within muscle Myo fibrils separated by vacuoles that stain with oils red O or Sudan black Occurs in type 1 fibers
35
What is seen in mitochondrial myopathies?
Aggregate of abnormal mitochondria Ragged red fibers Para crystalline parking lot inclusions
36
How do people with mitochondrial myopathies present?
With proximal muscle weakness | External ophthalmoplegia
37
What is dermatomyositis?
Inflammatory myopathy where there is antibody attack on the microvasculature so there is foci of ischemic myocyte necrosis
38
What is the morphology of dermatomyositis?
Inflammatory infiltrates around small blood vessels and in perimysium Perifascicular atrophy Necrotic muscle fibers and regeneration
39
What are the sx of dermatomyositis?
Iliac or heliotrope rash of upper eyelids with peri orbital edema Groton lesions= scaling erythmatous eruption or dusky red patches over knuckles, elbows, knees
40
What disease has antibodies directed against tRNA synthetase?
Polymyositis
41
What disease is ANA positive, mediated by CD8 T cells and macrophages with infiltrates in the endomysium?
Polymyositis
42
What disease involves the distal muscles, has asymmetric weakness, amyloid deposition and is not improved by immunosuppressive therapy?
Inclusion inflammatory myopathy
43
What is the auto dom mutation in inclusion?
Mutation in gene for myosin heavy chain IIa
44
What is the auto recessive mutation for inclusion?
Mut in GNE gene
45
What is seen in inclusion?
Rimmed vacuoles Amyloid deposition Hyperphosphorylated tau protein
46
What disease present with proximal muscle weakness, exophthalmic ophthalmoplegia, cramping muscles, slowed reflexes, and episodic weakness with hypokalemic?
Thyrotoxic myopathy
47
What presents with acute pain of a single muscle group and myoglobinuria?
Ethanol myopathy
48
Which fibers are affected in steroid myopathy?
Type 2
49
What myopathy is associated with presence of vacuoles in the myocytes, autophagic membrane, curvilinear bodies?
Chloroquine myopathy
50
What myopathy is associated with dilation of the SR and thickening of the basal laminate and atrophy of type 2 fibers?
Steroid myopathy
51
What disease is associated with antibodies to the acetylcholine receptor?
Myasthenia gravis
52
What disease is associated with thymic hyperplasia, t | Type 2 atrophy, ptosis, diplopia, decreased motor response with repeated stimulation?
Myasthenia gravis
53
Who gets myasthenia gravis?
Women before 40
54
What is the treatment for myasthenia gravis?
Thymectomy Prednisone Plasmapheresis Anticholinesterase agents
55
What develops as a paraneoplastic process?
Lambert eaton myasthenic syndrome
56
What disease has fewer vesicles synapse in response to an action potential?
Lambert eaton
57
What disease has enhanced neurotransmission with repeated stimulation?
Lambert eaton
58
What disease manifests as progressive muscle atrophy below the knee in childhood, palpable nerves and is autosomal dominant?
HMSN I
59
What is the most common mutation of HMSN I?
Mut in PMP22 - transmembrane protein in myelin
60
What disease has a mutation in KIF1B, is auto Dom and has no nerve enlargement?
HMSN II
61
What disease has depressed DTRs, auto recessive, palpable nerves, presents in early childhood?
Dejerine soltas neuropathy
62
What disease is auto recessive and destroys the anterior horn cells and CN motor neurons?
Spinal muscular atrophy
63
What is the mutation in spinal muscular atrophy?
SMN1 on ch.5 required for motor neuron survival
64
What is seen in spinal muscular atrophy?
Panfasciculad atrophy Floppy baby Death with first 3 years

Med School Year 2 Flash Cards (18 decks)

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