Peripheral Neuropathies and ALS

Question 1

Mononeuropathy

Answer 1

Focal involvement of a single nerve

Question 2

Examples of mononeuropathy

Answer 2

Median: Carpal tunnel
Ulnar: cubital tunnel
Radial: wristdrop
Peroneal: foot drop
(compression, trauma or entrapment)

Question 3

Mononeuropathy multiplex

Answer 3

Damage to one or more peripheral nerves (at random and noncontigous)
Pattern early on is asymmetric

Question 4

Polyneuropathy

Answer 4

Several peripheral nerves affected at same time

Presents as distal and symmetric deficit

Question 5

How to classify the problem

Answer 5

(based on structure affected)
Axon (axonal or neuronal)
Myelin (demyelinating)

Question 6

Most common neuropathy

Answer 6

Diabetic polyneuropathy

Question 7

Neuropathy

Answer 7

Axon is target

May see motor and sensory deficits but SENSORY usually precedes motor

Question 8

Neuronal neuropathy

Answer 8

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

Question 9

Examples of neuronal neuropathy

Answer 9

Type 2 Charcot Marie tooth hereditary

Vitamin B6 toxicity

Question 10

Demyelinating neuropathies

Answer 10

Involve myelin sheath surrounding axon

Often autoimmune or inherited (Guillain Barre, chronic inflammatory demyelinating polyneuropathy or charcot marie tooth)

Question 11

What is Guillain Barre Syndrome?

Answer 11

Idiopathic inflammatory neuropathy

Demyelinating

Question 12

When do you see Guillain Barre more

Answer 12

After infection (campylobacter jejuni!!)

Question 13

Presentation of Guillain Barre Syndrome

Answer 13

Ascending weakness (symmetric) usually beginning in legs
Sensory usually
Absent DTRs frequently
Maybe autonomic dysfunction

Question 14

What is chronic inflammatory demyelinating polyneuropathy?

Answer 14

Idiopathic inflammatory neuropathy (slowly progressive or relapsing)

Question 15

Presentation of CIDP

Answer 15

Diffuse hyporeflexia or areflexia
Diffuse weakness
Generalized sensory loss

Question 16

What is Charcot-Marie-Tooth?

Answer 16

Hereditary motor and sensory neuropathies (genetically heterogenous group of disorders with similar clinical phenotype)

Question 17

Presentation of Charcot Marie Tooth

Answer 17

Weakness
Wasting of distal muscles in limbs (with or without sensory loss)
Pes cavus
Reduced or absent DTRs

Question 18

Timing types

Answer 18

Acute (days to 4 wks)
Subacute (4-8 wks)
Chronic (>8 wks)

Question 19

Cause of acute mononeuropathy

Answer 19

Probably traumatic or ischemia

Question 20

Cause of chronic mononeuropathy

Answer 20

-More common

Entrapment or recurrent minor trauma

Question 21

Cause of acute polyneuropathy

Answer 21

Think inflammatory process (Guillain-Barre, neoplasms, infection, toxins)

Question 22

Cause of chronic polyneuropathy

Answer 22

Hereditary or metabolic, CIDP (gradual evolution over yrs)

Question 23

Peripheral vs motor vs sensory nerves

Answer 23

Peripheral: sensory, motor and autonomic elements
Motor: large myelinated fibers
Sensory: large for proprioception and small for pain and temp

Question 24

Sxs associated with motor nerve problems

Answer 24

Weakness
Fatigue
Cramps
Muscle twitches

Question 25

Signs of motor nerve problems

Answer 25

Weakness Muscle wasting Fasciculations

Question 26

Sxs associated with sensory nerve probs

Answer 26

Numbness or loss of sensation Altered sensation Neuropathic pain (burning, dull, poorly localized or sharp) Loss of coordination/imbalance

Question 27

Signs of sensory nerve probs

Answer 27

``` Sensory loss (sharp/dull, light touch, temp, vibration etc) Loss of proprioception ```

Question 28

First thing to be lost in pts with polyneuropathies

Answer 28

Ankle reflexes

Question 29

Autonomic sxs

Answer 29

``` Postural hypotension Tachycardia Cold extremities Impaired thermoregulatory sweating Bowel and bladder dysfunction Impotence ```

Question 30

Example of chronic axonal polyneuropathy

Answer 30

Diabetes

Question 31

History seen with chronic axonal polyneuropathies

Answer 31

Sxs begin in LE Sensory sxs usually before motor Slowly progressive, dysesthesias, mild gait probs Stocking glove distribution

Question 32

PE for chronic axonal polyneuropathies

Answer 32

Distal loss of sensation to pin prick, light touch, vibrations, temp or proprioception May see muscle wasting of feet or lower leg Hypoactive or absent reflexes

Question 33

Most common acute demyelinating polyneuropathy

Answer 33

Guillain Barre

Question 34

History seen with acute demyelinating polyneuropathy

Answer 34

Mostly affecting motor nerve fibes Weakness is usually the early sign Dysesthesias distally later on May have gait difficulties or hand clumsiness

Question 35

PE with acute demyelinating polyneuropathy

Answer 35

``` Generalized weakness (distal muscles) Abnorm vibratory and proprioception (out of proportion to loss of pin prick or temp sensation)-mostly large myelinated fibers ```

Question 36

Myopathy vs neuropathy

Answer 36

Myopathies have PROXIMAL motor weakness while neuropathies have DISTAL motor weakness (if any sensory loss or change in reflexes than neuropathy)

Question 37

Radiculopathy

Answer 37

Different distributions of motor and sensory deficits (segmental pattern) Neck or back pain that radiates to extremities in radicular distribution is probably root lesion

Question 38

B12 deficiency

Answer 38

``` Symmetrical neuropathy (LEGS more than arms) Paresthesias and ataxia first with loss of vibration and proprioception ```

Question 39

Motor neuron diseases

Answer 39

Sxs of upper and/or lower motor neuron dysfunction WITHOUT sensory sxs

Question 40

What can electrodiagnostic testing do?

Answer 40

Differentiate axonal or demyelinating in character | See is primary nerve or muscle disorder

Question 41

Nerve conduction study

Answer 41

Permit conduction velocity to be measured in motor and sensory fibers

Question 42

Electomyography

Answer 42

May show denervation of affected muscles

Question 43

Tx of Guillain Barre

Answer 43

Plasmapheresis and IVIG | No steroids!!!!

Question 44

Tx of CIDP

Answer 44

Steroids and IVIG (consider plasma exchange)

Question 45

Pharm tx for neuropathic pain

Answer 45

NSAIDs (mild) *Gabapentin, pregabalin, TCAs Maybe duloxetine, venlafaxine or carbamazepine

Question 46

Most common form of motor neuron disease

Answer 46

Amyotrophic lateral sclerosis (ALS)

Question 47

Presentation of ALS

Answer 47

Relentlessly progressive, incureable neurodegenerative disorder (muscle weakness and disability) Mixed upper and lower motor neuron deficit in limbs Normal sensory exam!! Usually presents in 1 of 4 body segments (cranial/bulbar, cervical, thoracic and lumbosacral) and then spreads Involuntary muscle wasting and weight loss

Question 48

PE to distinguish lower and upper motor neuron

Answer 48

Lower: weakness, atrophy, muscle cramps, hypo-reflexia, fasciculations! Upper: slowness, incoordination, increased tone, hyperreflexia, spasticity, clonus

Question 49

How to diagnose ALS

Answer 49

Clinically (NCS normal, EMG might show diffuse ongoing chronic denervation)

Question 50

Median survival of ALS

Answer 50

3-5 yrs (survival beyond 20 very rare)