Disorders of the peripheral nervous system

Question 1

What symptoms do you get if large fibre motor nerves are injured?

Answer 1

• Muscle wasting
• Reduced power
• Unsteadiness

Question 2

What symptoms do you get if large fibre sensory nerves are injured?

Answer 2

Symptoms can vary
-Numbness
-Paresthesia
-Unsteadiness

Question 3

What symptoms do you get if small fibre nerves are injured?

Answer 3

-Pain
-Dysesthesia

Question 4

What symptoms do you get if autonomic nerves are injured?

Answer 4

-Postural hypotension (dizziness)
-Impotence
-Nausea & vomiting
-Absence of sinus rhythm

Question 5

What are key defining features of each nerve type being damaged?

Answer 5

Large fibre motor - Reduced power
Large fibre sensory - Paresthesia
Small fibre - Pain
Autonomic- Nausea & vomiting + loss of sinus rhythm

Question 6

What is damage at the roots/spinal nerve called?

Answer 6

Radiculopathy/ganglionopathy

Question 7

What is a plexus injury called?

Answer 7

Plexopathy

Question 8

What is a peripheral nerve injury called?

Answer 8

Peripheral neuropathy

Question 9

What is it called when one peripheral nerve is injured?

Answer 9

mononeuropathy

Question 10

What is the most common type of nerve injury?

Answer 10

Peripheral neuropathy

Question 11

What is the most common pattern of sensory loss in peripheral neuropathy?

Answer 11

Symmetrical distal sensory loss

Question 12

What nerve is affected in wrist drop?

Answer 12

Radial nerve

Question 13

What nerve is affected in foot drop?

Answer 13

Common peroneal nerve

Question 14

What are the mechanisms behind peripheral nerve damage?

Answer 14

-Axonal loss
OR
-Demyelination

Question 15

What does motor nerve conduction velocity tell us about the axon/myelin sheath?

Answer 15

The integrity of the myelin sheath

Question 16

What does waveform tell us about the axon/myelin sheath?

Answer 16

The integrity of the axon

Question 17

In a demyelinating injury what happens to the information travelling through the nerve?

Answer 17

It arrives asynchronously at different times

Question 18

Name an acute demyelinating neuropathy

Answer 18

Guillain-Barre Syndrome

Question 19

What are some key signs of Guillain-Barre Syndrome?

Answer 19

• Progressive paraplegia over days - 4 weeks
• Associated sensory symptoms proceeding weakness
• Pain very common

Question 20

When do Guillain-Barre Syndrome symptoms peak?

Answer 20

10-14 days into onset of illness

Question 21

How is Guillain-Barre Syndrome treated?

Answer 21

immunoglobulin infusion or plasma exchange

Question 22

Name some chronic demyelinating neuropathies?

Answer 22

-CIDP (chronic inflammatory demyelinating polyradiculopathy)
-Hereditary sensory motor neuropathy

Question 23

Name the types of axonal neuropathies?

Answer 23

-Idiopathic
-Vasculitic
-Paraneoplastic
-Infections
-Drugs/toxins
-Metabolic

Question 24

How can peripheral axonal neuropathy be treated?

Answer 24

• Treat cause (e.g. Clearing Hep C)
• Symptomatic treatment (physio, analgesia etc.)

Question 25

How can vasculitic peripheral axonal neuropathy be treated?

Answer 25

Pulsed IV Methylprednisolone + Cyclophosphamide

Question 26

How can demyelinating (inflammatory neuropathy) peripheral neuropathy be treated?

Answer 26

• IVIg (immunoglobulin from donors)
• Steroids
• Azathioprine, Mycophenolate, Cyclophosphamide

Question 27

What are the three types of peripheral neuropathy?

Answer 27

• Mononeuropathy
• Mononeuritis Multiplex
• (length dependent) peripheral neuropathy