Peripheral Nervous System And Skeletal Muscles Pathology Dr. Martin

Question 1

motor unit consists of

Answer 1

axon,
lower motor neuron,
muscle fibers

Question 2

peripheral nerve consists of

Answer 2

nerve fiber + myelin, schwann cells ( have nodes of ranvier, each schwann cell covers 1 internode)

Question 3

Epineurium

Answer 3

encloses entire peripheral nerve

Question 4

Perineurium

Answer 4

multilayered concentric CT that encloses each fascicle

Question 5

Endoneurium

Answer 5

surrounds each nerve fiber

Question 6

Axonal degeneration involves and does what

Answer 6

axon and neuron , can cause axon regeneration and reinnervation of muscle

Question 7

Segmental Demyelination

Answer 7

myelin breakdown in segments

Question 8

denervation atrophy vs myopathy

Answer 8

1. denervation atrophy : loss of axon causes atrophy of muscle
2. Myopathy : abnormal muscle fiber itself

Question 9

segmental demyelination of schwann cell vs myelin sheath

Answer 9

1. schwann cell : hereditary or sensory neuropathy

2. myelin : guillain barre

Question 10

denuded axon

Answer 10

remyelination signal (new myelin in shorter in length then normal myelin)

Question 11

cross section of thin myelin on a nerve looks like

Answer 11

onion cut (onion bulb)

Question 12

Traumatic neuroma

Answer 12

axons that cant find their distal target (muscle) = pseudotumor made (non-neoplastic whorled proliferation of axonal processes and
= CAUSES PAINFUL NODULE

Question 13

Wallerian degeneration

Answer 13

focal lesion in axon (distal part of axon is damaged

Question 14

Axon damage

Answer 14

from ischemia or trauma = whole neuronal body or its axon

Question 15

axonal degeneration

Answer 15

primary destruction of axon and myelin

Question 16

axonal degeneration steps of what happens after

Answer 16

1. Myelin Ovoids : schwann cells catabolize myelin + later engulf axon fragments = oval compartment made
2. M clean them up
3. proximal part of severed nerve degenerates in 2-3 distal internodes
4. regenerates

Question 17

axonal degeneration shows what SIGNS on histology of nerve

Answer 17

1. Denervation Atrophy
2. Angulated ends (smaller and triangle shaped muscle fibers
3. Target Fibers

Question 18

what determines the fiber type

Answer 18

motor neuron

Question 19

group atrophy

Answer 19

a type group (muscle fiber type) gets denervated

Question 20

type 2 fiber atrophy can happen from

Answer 20

= inactivity
= diffuse (limb fracture, pyramidal tract degeneration, neurodegenerative dz)
= STERIOID MYOPATHY (from glucocorticoids)

Question 21

1. hypertrophy does what to muscle fiber

and 2. segmental necrosis

Answer 21

1. splitting of fiber (from increased exercise = fibers split)
2. deposits of collagen and fat

Question 22

Regenerated nerves stain how

Answer 22

cytoplasm laden with RNA = RED trichrome stain

Question 23

somatic motor function travel how

Answer 23

1. lower motor N on ANTERIOR HORN

2. to muscle fiber

Question 24

Somatic Sensory nerve travels how

Answer 24

1. distal nerve ending (specialized sensory structures) pick up signal
2. travels with peripheral N to DORSAL ROOT GANGLION
3. go to brain to synapse at SPC and brainstem

Question 25

Autonomic nerve fiber problems involves what disease

Answer 25

Diabetic neuropathy

Question 26

unmyelinated fibers

Answer 26

temp and pain = slow conduction

Question 27

large axon with myelin

Answer 27

light touch, motor signals | = fast conduction

Question 28

Axonal Neuropathy 1. targets what never usually and causes what 2. physiologic hallmark

Answer 28

1. longest neuron = dying back progression | 2. reduction of amplitude, PRESERVATION of conduction velocity

Question 29

electrophysiologic hallmark of demyelinating neuropathy

Answer 29

SLOWED nerve conduction,

Question 30

Neuronopathies

Answer 30

destruction of neurons (infection Herpes Zoster, Toxins platinum) = effects proximal and distal body equally (HALLMARK)

Question 31

peripheral neuropathy SX

Answer 31

1. tingling, stabbing, buring, or pins and needles

Question 32

peripheral neuropathy : polyneuropathies

Answer 32

1. many nerves usually symmetric 2. starts distal and ascends 3. hands involved usually at level of knee (stocking and glove)

Question 33

Mononeuritis Multiplex :

Answer 33

many nerves damaged in haphazard distribution | VASCULITIS ---> Polyarteritis nodosum PAN

Question 34

mononeuropathies

Answer 34

single nerve effected

Question 35

Bell's Palsy 1. effects what 2. age 3. SXX

Answer 35

1. CN 7 mononeuropathy (facial muscle paralysis) 2. 15-60yo (resolves spontaneously) 3. one side facial droop , facial tingling, headache + neck pain, memory prob, balance issues, SAME side limb paresthesias, low tears tasting saliva)

Question 36

Bell's Palsy associated with what and can look like what conditions

Answer 36

1. DM and URI | 2. stroke, brain tumor, Ramsay Hunt Syndrome (type 2 herpes zoster) , Lyme disease

Question 37

Neurologenic bladder 1. is what 2. can be caused by degenerative dz 3. can be caused by what else

Answer 37

1. lack of bladder control from spinal cord or nerve problem 2. Parkinsons, DM, MS 3. infection brain or SC , heavy metal, stroke, SC or pelvic injury

Question 38

Neurologenic bladder can be seen in what congenital condition

Answer 38

spina bifida

Question 39

Neurologenic bladder 4 types of things what nerves are damaged for the bladder 1. Hypogastric nerve 2. pelvic nerve 3. pudendal nerve

Answer 39

1. overactive bladder 2. underactive bladder 3. incontinence (cant hold) 4. obstructive bladder (can empty)

Question 40

Guillain Barre 1. first sx seen 2. nerve effected and what happens

Answer 40

1. Loss of deep tendon reflexes or flu illness after recovery (Campylobacter jejuni, CMV, EBV, Mycoplasma pneumonia, vaccine) 2. multifocal destruction of myelin (Demyelination + inflammation) of SPINAL nerve ROOTS + PERIPHERAL NERVES = Radiculoneuropathy

Question 41

Guillain Barre 1. type of neuropathy 2. histology seen 3. DX by

Answer 41

1. ascending polyneuropathy 2. perivenular + endoneurial infiltration of inflammatory cells (SEGMENTAL DEMYELINATION) 3. Anti-Myelin ABs

Question 42

Guillain Barre : 1. where to M like to eat 2. CSF findings 3. TX

Answer 42

1. right by the Nodes of Ranvier (it can go under myelin and strip it away) 2. HIGH protein (from permeability increase) LOW WBCs they stay at the roots 3. Plasmapheresis IVIg

Question 43

Chronic Inflammatory Demyelinating Poly(radiculo)neuropathy: 1. what type of neuropathy 2. dx criteria 3. caused by 4. different then Guillan Barre how

Answer 43

1. most common acquired, symmetric 2. persists for at least 2mo 3. T cells and B cells (ABs) against myelin, IgG and IgM found 4. responds to steroids

Question 44

Chronic Inflammatory Demyelinating Poly(radiculo)neuropathy: histology looks like and how to dx

Answer 44

Biopsy of sural nerve : ONION BULBS seen (many schwann cell layers look like onion rings (recurrent demyelination and remyelination)

Question 45

systemic autoimmune diseases causing peripheral neuropathy and what type

Answer 45

SLE*, RA, Sjögrens | = distal sensory or sensorymotor

Question 46

Vasculitis causing neuropathy : 1. type neuropathy 2. type of vasculitits 3. most common vasculitis causing this 4. histo

Answer 46

1. mononeuritis multiplex 2. MPO-ANCA (microscopic PA, Eosinophilic granulomatosis, Churg-Strauss) + PAN + PR3-ANCA (GPA) 3. Nonsystemic vasculitic neuropathy 4. patchy axonal degeneration

Question 47

Leprosy and neuropathy : Lepromatous Leprsy 1. caused by 2. what happens 3. histo 4. involves what

Answer 47

1. Mycobacterium leprae attacking myelin 2 . Symmetric Segmental demyelination + remyelination (LOSS of myelinated + unmyelinated axons 3. Endoneurial fibrosis + multilayerd thickening of perineural sheaths 4. pain fibers , loss of sensation (likes COOL extremitis)

Question 48

Leprosy and neuropathy : Tuberculoid Leprosy 1. what happens 2. sx + location 3. what histo

Answer 48

1. active cell mediated immune response 2. granulomatous nodules on dermis, localized nerve involvement (Cutaneous nerves) 3. fibrosis of perineurium and endoneurium

Question 49

Lyme dz and neuropathy

Answer 49

BILATERAL facial nerve palsy | (polyradiculoneuropathy

Question 50

HIV and neuropathy 1. type of neuropathy (early stage) 2. SX and what happens 3. late stage

Answer 50

1. Mononeuritis multiplex 2. Demyelination looking like Guillain Barre, chronic inflammatory demyelinating polyradiculopathy 3. Distal sensory neuropathy

Question 51

Diphtheria and vasculitis 1. SX 2. from what 3. location effected 4. Associated SX****

Answer 51

1. paresthesia and weakness, loss of proprioception and vibratory sensation 2. bacteria exotoxin (not vaccinated or waning immunity) 3. demyelination of axons extending to Anterior Root + Posterior Root + Mixed sensorimotor nerves 4. PROMINENT BULBAR + RESPIRATORY MUSCEL DYSFUNCTION = DEATH or long term disability

Question 52

Varicella Zoster Virus and Neuropathy : 1. effects what 2. can cause what type of problem 3. SXs

Answer 52

1. sensory ganglia degeneration+ large motor neurons in ANTERIOR HORN + cn nuceli 2. reactivation = shingles + painful vesicular skin eruptions (trigeminal or thoracic nerve dermatomes) 3. regional necrosis, hemorrhage, loss of effected ganglia (burning, tingling, itching)

Question 53

most common cause of peripheral neuropathy

Answer 53

DM2 and DM1

Question 54

Diabetes and neuropathy 1. type and how it acts 2. SX 3. can cause what to lead to morbidity

Answer 54

1. ascending distal symmetric sensorimotor polyneuropathy (loss of axons) 2. numbness, tingling, loss of pain, difficult balance 3. low sensation in feet causing ulcers and amputation + diffuse vascular injury

Question 55

Diabetic neuropathy 1. histo and nerves effected 2. ANS dysfuntion condition 3. peripheral neuropathy condition

Answer 55

1. loss of myelinated and unmyelinated small fibers + large , ENDOONEURIAL ARTERIOLES thick and hyalinized, PAS+ and duplicated BM**** 2. postural hypotension, cant empty bladder (uti), sexual dysfunction 3. ASYMMETRIC mononeuropathy, cranial neuropathy, radiculoplexus neuropathy

Question 56

Diabetes and neuropathy progresses due to what 2 things

Answer 56

vascular and metabolic changes contribute

Question 57

Cartilage forming tumors : Osteochondroma 1. location 2. age 3. morphology 4. B or M 5. B

Answer 57

1. metaphysis of long bones 2. 10-30 yo 3. bony excrescence with cartilage

Question 58

Cartilage forming tumors : Chondroma 1. location 2. age 3. morphology 4. B or M

Answer 58

1. small bones of feet and hands 2. 30yo-50yo 3. circumscribed hyaline cartilage nodule in medulla 4. B

Question 59

Cartilage forming tumors : Chondrosarcoma 1. location 2. age 3. morphology 4. B or M

Answer 59

1. shoulder and pelvis 2. 40yo-60yo 3. extends from medulla through cortex into soft tissue, atypic chondrocytes

Question 60

Bone forming tumors : Osteoid osteoma 1. location 2. age 3. morphology 4. B or M

Answer 60

1. Metaphysis of long bone 2. 10-20yo 3. cortical, interlacing microtrabeculae of woven bone 4. B

Question 61

Bone forming tumors : Osteosarcoma 1. location 2. age 3. morphology 4. B or M

Answer 61

1. metaphysis of distal femur, proximal tibia 2. 10yo-20yo 3. Extends from medulla to lift periosteum, malignant cells producing woven bone

Question 62

unknown orgin tumors : Ewing Sarcoma 1. location 2. age 3. morphology 4. B or M

Answer 62

1. Diaphysis of long bone 2. 10-20yo 3. sheets of primitive small round cells 4. M

Question 63

Uremic Neuropathy 1. who gets this 2. what happens SX 3. what happens to nerves

Answer 63

1. renal failure pts 2. peripheral neuropathy = Distal Symmetric Neuropathy (asymptomatic, muscle cramps, low reflex, distal dysesthesias) 3. axon degeneration (after dialysis recovers and regenerated)

Question 64

Thyroid Dysfunction : hypothyroidism 1. causes what 2. rare association

Answer 64

1. compression mononeuropathies (carpal tunnel) , distal symmetric sensory neuropathy 2. Guillain Barre

Question 65

Vit12 deficiency : 1. what happens 2. other name for this vitamine

Answer 65

1. subacute combined degeneration with damage to long tracts in the spinal cord + peripheral nerves 2. cyanocobalamin

Question 66

Vitamines associated with peripheral neuropathy

Answer 66

1. B1 (Thiamine) 2. B6 (pyridoxine) 3. Folate 4. copper 5. Zinc

Question 67

metals and chemotx associated with peripheral neuropathy

Answer 67

1. EtOH, Pb, Mercury, arsenic, thallium) | 2. Vinca alkaloids, taxanes, microtuble inhibitors, cisplatin

Question 68

Neuropathies form malignancy 1. brachial plexopathy 2. Obturator Palsy 3. Cranial palsy 4. Polyradiculopathy of lower extremities 5. Sensorimotor neuropathy

Answer 68

1. Brachial plexopathy : apex of lung 2. Obturator Palsy : pelvic tumor 3. Cranial palsy : cranial tumor 4. Polyradiculopathy : cauda equina involved in carcinomatosis 5. sensorimotor neuropathy : Small cell lung Carcinoma

Question 69

sensorimotor neuropathy : Small cell lung Carcinoma presents how and DX how

Answer 69

1. DX : anti-Hu antibodies 2. start distally and asymmetric, mutlifocal 3. if pt has Anti-CV2 (painful axonal asymmetric sensorimotor neuropathy

Question 70

Neuropathy associated with | 1. monoclonal gammopathies , what happens, and SX

Answer 70

1. B-cell neoplasm** 2. IgM demyelination peripheral neuropathy, IgG and IgA also cause peripheral neuropathy 3. POEMS (polyneuropathy, organomegaly, endocrinopathy, monoclonal gammopathy, skin changes

Question 71

excess Ig can deposit how and cause

Answer 71

as amyloid, can lead to peripheral neuropathy, vascular insufficiency, direct toxic effect

Question 72

sympathetic chain syndrome can happen is what malignancy condition

Answer 72

Hornes Syndrome

Question 73

Traumatic neuroma

Answer 73

``` regenerated slowly (axons are misaligned and continue to grow) =random oriented axons = can happen from trauma ```

Question 74

carpal tunnel syndrome what, sx, associated with

Answer 74

1. entrappment of medial N 2. numbness and paresthesia of tip of thumb and 1st 2 digits 2. edema, preg, inflammatory arthritis, hypothyroidism, amyloid diabetes, wrist motions

Question 75

Saturday night palsy

Answer 75

radial nerve upper arm , fall asleep weird

Question 76

elbow and knee nerve compression

Answer 76

ulnar and peroneal

Question 77

Morton Neuroma

Answer 77

metatarsalgia, perineural fibrosis

Question 78

Inherited Peripheral Neuropathy : Hereditary Motor and Sensory Neuropathy 1. other name 2. sx 3. 4 genes and there causes

Answer 78

1. Charcot- Marie Tooth (CMT) 2. distal muscle atrophy, sensory loss, for deformities 3. CMT1**** = AD demyelination (Chr17 PMP22 gene) most common CMT1B = mutation in MPZ demyleination CMTX = X-linked , GJB1 gene CMT2 = AD axonal injury *(severe and early childhood) MFN2 gene

Question 79

Inherited Peripheral Neuropathy : Hereditary Sensory Neuropathy 1. what happens 2. sx

Answer 79

1. loss sensation + other ANS (KEEPS MOTOR), axonal neuropathy 2. Loss of pain and temperature, cant feel pain (can lead to big injuries)

Question 80

Inherited Peripheral Neuropathy : Familial Amyloid Polyneuropathies 1. what happens 2. mutation 3. associated with

Answer 80

1. Amyloid on peripheral nevers 2. Transthyretin gene 3. metabolic disfunctions

Question 81

NMJ problems present as

Answer 81

painless weakness and fatigue

Question 82

2 most common NMJ problem diseases

Answer 82

1. Myasthenia Gravis | 2. Lambert Eaton

Question 83

Myasthenia Gravis : 1. what is the cause 2. associated with what 3. histology

Answer 83

1. AB against AchR 2. thymoma or thymic hyperplasia 3. B-cell follicles in thymus

Question 84

Myasthenia Gravis : 1. SX 2. DX how 3. TX how

Answer 84

1. generalized fluctuating weakness worse with exertion and over day, repeated stimulation cause diminished response, Drooping eyelid, extraocular muscle weakness = diplopia 2. decrease response to repeated stimuli 3. Acetylcholinesterase Inhibitors, thymectomy, plasmapheresis

Question 85

Lambert-Eaton Myasthenic Syndrome : 1. happens how 2. Paraneoplastic to what 3. SX 4. TX

Answer 85

1. AB against presynaptic CA channel = no Ach release 2. Neuroendocrine carcinoma (Small Cell Carcinoma) 3. proximal weakness in extremities, INCREASE response during repeated stimuli 4. increase Ach release (depolarize membranes)

Question 86

Congenital Myasthenic Syndrome 1. what happens 2. SX

Answer 86

1. muscle weakness due to AchR mutation | 2. perinatal period, poor muscle tone, external eye muscel weakness, breathing probs

Question 87

Clostridium Botulinum can do what

Answer 87

Botox blocks Ach release

Question 88

Curare does what

Answer 88

blocks AchR = flaccid paralysis