Peripheral Neuropathy Part 1

Question 1

Why do peripheral neuropathies first manifest distally?

Answer 1

Because they target the most metabolically active nerves in the body (which happen to be the longest nerves in the body)

Question 2

List and discuss the three grades of physical nerve injury according to ‘Seddon’

Answer 2

Neurapraxia - mildest type: is a conduction block in which function returns
Axonatomesis - axonal discontinuity: interruption of axon and myelin sheath
connective tissue of nerve is fine and so is cell body so therefore nerve is able to regenerate
neurotomesis - partial or full severance of the nerve ‘discontinuity’ resolution with surgery

Question 3

List the three main type of degeneration seen when neuons are injured. In each case give a brief definition and description of the key features of each type

Answer 3

Axonal degeneration:

Segemental demyelination:

Wallerian degeneration:

Question 4

List and briefly discuss the types of axonal degeneration

Answer 4

Neuronopathic axonal degeneration- neuronal cell body dies i.e. MND

Distal axonal neuropathy - neuronal cell body under stress but doesn’t die

Question 5

Define the term segmental demyelination

Answer 5

Focal degeneration of the myelin sheath with sparing of the axon. Occurring mainly in focal neuropathies; also seen in sensorimotor or predominantly motor neuropathies

Question 6

Name and discuss the types of segmental demyelination

Answer 6

Primary:
Schwann cell degeneration
Secondary:
Axon degeneration

Question 7

Can axons regenerate? discuss

Answer 7

yes if the cell body is not damaged

Question 8

Define the term mononeuropathy

Answer 8

When a single peripheral nerve is affected

Question 9

List the common causes of mononeuropathy

Answer 9

vascular diseases, nerve compression, immune, infectious, trauma

Question 10

Discuss why the clinical manifestations of mononeuropathy may vary from case to case

Answer 10

Depends on whether the nerve root, nerve plexus or peripheral nerve is affected

Question 11

Write notes on the following mononeuropathies

Answer 11

Carpal tunnel syndrome
Ulnar neuropathy
Radial neuropathy
Peroneal Palsy

Question 12

Define the term mono neuritis multiplex

Answer 12

When several peripheral nerves are affected at a specific point in time

Question 13

What is the main cause of mono neuritis multiplex

Answer 13

vasculitis

Question 14

List two diseases capable of causing mono neuritis multiplex

Answer 14

diabetes and ?

Question 15

does mono neuritis multiplex differ from peripheral poly neuropathy? discuss

Answer 15

yes poly neuropathy is when all peripheral nerves are affected symmetrically at a specific point in time i.e. bilateral and same distribution of loss
mononuritis multiplex affects more than on peripheral nerve but no symmetrically

Question 16

List all the causes of peripheral polyneuropathy

Answer 16

inflammatory - GBS
metabolic - diabetes/renal failure 
nutritional - thiamine deficiency
toxic - drugs, heavy metals (arsenic/gold/mercury) organic solvents (acetone) 
familial - charcot-marie-tooth disease