Polyneuropathy

Question 1

What kind of nerves are affected in polyneuropathies?

Answer 1

3 types of nerve in the PNS:

Somatosensory (most common)
LMN
Autonomic

Question 2

Describe the clinical picture of polyneuropathy

Answer 2

• distal onset
• Hypotonia and atrophy
• decreased tendon reflexes and sensation
• pain and paresthesia, from distal to proximal
• proprioceptive complications
• autonomous complications

Question 3

Electrophysiological differentiation of polyneuropathies

Answer 3

Axonal involvement: low AP amplitude, mild decrease in CV, no conduction block

Demyelination: low AP amplitude, decreased CV, conduction block

Axonal: AP
Demyelination: CV

Question 4

On which part of the nervous system do polyneuropathies take effect?

Answer 4

Affecting peripheral nerves
Diffuse dysfunction of PNS

Injury of nerves in a symmetrical pattern

Question 5

What are the findings in a CT scan or an MRI?

Answer 5

spinal channel: stenosis, herniation, Tumors
root injury: compression and inflammation
plexus: tumoral Compression or infiltration
nerve trunks: compression
Muscle atrophy

Question 6

Which nerve can be used in a biopsy for further investigations?

Answer 6

Sural nerve (sensory nerve of leg, from tibial and common fibulae nerves)

Question 7

Classification of polyneuropathies

Answer 7

Acute: symmetrical involvement, proximal and distal, predominantly motor

Subacute: symmetrical and asymmetrical, sensory motor

Chronic: acquired, inherited

Question 8

Definition of Guillian Barre Syndrome

Answer 8

= acute inflammatory polyradiculopathy (related to demyelination)

Autoimmune disease
Most common cause of acute weak flaccid paralysis

types:

• acute inflammatory demyelinating neuropathy
• acute motor axonal neuropathy

Question 9

Clinical signs of Guillain Barre syndrome

Answer 9

Acute ascending weakness, possibly leading to total paralysis within hours

Areflexia

Numbness and paresthesia

Ataxia

Autonomic signs (arrhythmia, HTN)

Question 10

How is Guillain Barre syndrome diagnosed?

What are the risk factors?

Answer 10

First signs seen after 7 - 10 days:

Increased protein content in CSF
possible pleocytosis
Electrophysiology: demyelination

During the first 2 - 3 weeks, increased risk of death due to respiratory failure and cardiovascular instability

Question 11

Treatments of Guillain Barre syndrome

Answer 11

IV immunoglobulins: 2g/kg/5d

Plasmapheresis

Question 12

How are myopathies studied?

Answer 12

Electrophysiology: (needle electrode recording)

Nerve conduction studies
Sensory conducting velocities