Peripheral neuropathies and ALS

Question 1

mononeuropathy or focal involvement of a single nerve is often due to

Answer 1

• trauma
• compression
• entrapment

Question 2

Meralgia paresthetica

Answer 2

• tingling, numbness and burning pain in your outer thigh
• lateral femoral cutaneous nerve

Question 3

define mononeuropathy multiplex

Answer 3

• damage to one or more peripheral nerves

Question 4

pattern of mononeuropathy multiplex early on is

Answer 4

asymmetric

Question 5

polyneuropathy predominantly presents as what type of deficit

Answer 5

• several peripheral nerves affected at the same time
• presents as a distal and symmetric deficit

Question 6

peripheral neuropathies are categorized into

Answer 6

• axon (axonal or neuronal neuropathies)
• myelin (demyelinating)

Question 7

in axonal neuropathies, what is the target

Answer 7

• axon

Question 8

most polyneuropathies falls into what category

Answer 8

• axonal neuropathies

Question 9

what is the most common type of polyneuropathy

Answer 9

• diabetic polyneuropathy

Question 10

in axonal neuropathies, may see both motor and sensory deficits but which usually precedes the other

Answer 10

• sensory usually preceeds motor symptoms

Question 11

neuronal neuropathies affect what

Answer 11

• nerve cell bodies in the anterior horn of the spinal cord or dorsal root ganglion

Question 12

List two examples of neuronal neuropathies

Answer 12

• type 2 charcot marie tooth hereditary neuropathy
• vitamin B6 toxicity

Question 13

demyelinating neuropathies involve what structure

Answer 13

• myelin sheath surrounding the axon

Question 14

demyelinating neuropathies are often caused by?

Answer 14

• autoimmune or inherited

Question 15

guillain barre syndrome is an example of

Answer 15

demyelinating neuropathies

Question 16

guillain-barre syndrome is an idiopathic inflammatory neuropathy that is associated with what infection

Answer 16

• campylobacter jejuni

Question 17

clinical presentation

• ascending weakness (symmetric), usually beginning in legs
• sensory complaints frequent
• DTRs frequently absent
• may have autonomic dysfunction

Answer 17

• guillain-barre syndrome

Question 18

describe chronic inflammatory demyelinating polyneuropathy

Answer 18

• idiopathic inflammatory neuropathy
• slowly progressive relapsing polyneuropathy
• diffuse hyporeflexia or areflexia
• diffuse weakness
• generalized sensory loss

Question 19

List the three types of charcot-marie-tooth hereditary motor and sensory neuropathies and what type they are

Answer 19

• CMT-1: demyelinating
• CMT-2: neuronal
• CMT-3: demyelination

Question 20

clinical presentation

• weakness
• wasting of distal muscles in the limbs (with or without sensory loss)
• pes cavus
• reduced or absent DTR

Answer 20

• charcot-marie-tooth

Question 21

differentiate between acute, subacute, and chronic peripheral neuropathies

Answer 21

• acute: up to 4 weeks
• subacute: 4 - 8 weeks
• chronic: > 8 weeks

Question 22

peripheral nerves are composed of what elements

Answer 22

• sensory
• motor
• autonomic

Question 23

size of proprioception and vibratory sensory fibers

Answer 23

large

Question 24

size of pain and temperature fibers

Answer 24

small

Question 25

what reflexes are usually the first to be lost in patients with polyneuropathies

Answer 25

* ankle reflexes

Question 26

autonomic symptoms associated with peripheral neuropathies

Answer 26

* postural hypotension * tachycardia * cold extremities * impaired thermoregulatory sweating * bowel and bladder dysfunction * impotence

Question 27

In chronic axonal polyneuropathies, such as diabetes, injury tends to be related to

Answer 27

* axon length * sx begin in the lower extremities

Question 28

in chronic axonal polyneuropathies, does sensory or motor sx come first

Answer 28

* sensory precedes motor

Question 29

stocking and glove distribution of sensory loss is associated with

Answer 29

* chronic axonal polyneuropathies

Question 30

in acute demyelinating polyneuropathies, such as guillain barre, what structures are primarily affected

Answer 30

* motor nerve fibers

Question 31

what is the earliest sign in acute demyelinating polyneuropathies

Answer 31

* **weakness** rather than sensory loss * distal muscles are predominantly affected

Question 32

in acute demyelinating polyneuropathies, large myelinated fibers are the most damaged. What should you see on physical exam

Answer 32

* abnormalities of vibratory testing and proprioception - out of proportion to loss of pin prick or temperature sensation

Question 33

myopathies usually present with whereas neuropathies present with

Answer 33

1. myopathies: **proximal** motor weakness 2. neuropathies: **distal** motor weakness

Question 34

Regardless if a patient presents with motor weakness, if there is **any** sensory loss and/or loss of relfexes - think

Answer 34

* neuropathy

Question 35

define radiculopathy

Answer 35

* nerve root lesions

Question 36

how can radiculopathy be differentiated from peripheral neuropathies

Answer 36

* in radiculopathy, nerve root involvement produces impaired cutaneous sensation in a **segmental** pattern

Question 37

clinical presentation * neuropathy is **symmetrical** * affects **legs** more than arms * begins with paresthesias and ataxia associated with **loss of vibration and position sense** * can progress to severe weakness, spasticitiy, clonus, paraplegia, and fecal/urinary incontinence

Answer 37

* B-12 deficiency

Question 38

what condition typically produces symptoms of upper and/or lower motor neuron dysfunction **without** sensory symptoms

Answer 38

* motor neuron disease

Question 39

nerve conduction study has what function

Answer 39

* permits **conduction velocity** tp be measured in motor and sensory fibers

Question 40

electromyography (EMG) has what function

Answer 40

* may reveal evidence of **denervation** in affected muscles

Question 41

what type of neuropathy typically reveals little or no evidence of denervation, but does show **conduction** block or marked slowing of maximal conduction velocity in affected nerves

Answer 41

demyelinating neuropathy

Question 42

what type of neuropathy typically reveals **denervation** changes but maximal nerve conduction velocity is normal or only slightly slowed

Answer 42

* axonal neuropathies

Question 43

what medication should not be given in tx of guillan-barre syndrome

Answer 43

steroids

Question 44

medication options for neuropathies

Answer 44

* **gabapentin/pregabalin** * **tricyclic antidepressants**

Question 45

what causes amyotrophic lateral sclerosis (ALS)

Answer 45

* 90% sporadic * caused by **degeneration of both upper and lower motor neurons** * leads to skeletal muscle atrophy, weakness, disability, and eventually death

Question 46

clinical presentation * progressive symptoms consistent with upper and lower motor neuron dysfunction * present in one of four body segments (**cranial, cervical, thoracic, and lumbosacral**) * spread to other segments in time

Answer 46

* amyotrophic lateral sclerosis (ALS)

Question 47

sensory exam in patients with amyotrophic lateral sclerosis (ALS) is usually

Answer 47

* normal

Question 48

signs of lower motor neuron disease

Answer 48

* weakness * atrophy * muscle cramps * hyporeflexia * fasciculations

Question 49

signs of upper motor neuron disease

Answer 49

* increased tone * incoordination * slowness of movement * hyper-reflexia * babinski * spasticity * clonus

Question 50

how is amyotrophic lateral sclerosis (ALS) diagnosed

Answer 50

* **clinically** * **​**EMG often reveals evidence of diffuse, ongoing, chronic denervation

Question 51

LMN + UMN deficits in 3 regions is consistent with

Answer 51

* definite ALS