Disorders of the peripheral nervous system Flashcards
What symptoms do you get if large fibre motor nerves are injured?
- Muscle wasting
- Reduced power
- Unsteadiness
What symptoms do you get if large fibre sensory nerves are injured?
Symptoms can vary
-Numbness
-Paresthesia
-Unsteadiness
What symptoms do you get if small fibre nerves are injured?
-Pain
-Dysesthesia
What symptoms do you get if autonomic nerves are injured?
-Postural hypotension (dizziness)
-Impotence
-Nausea & vomiting
-Absence of sinus rhythm
What are key defining features of each nerve type being damaged?
Large fibre motor - Reduced power
Large fibre sensory - Paresthesia
Small fibre - Pain
Autonomic- Nausea & vomiting + loss of sinus rhythm
What is damage at the roots/spinal nerve called?
Radiculopathy/ganglionopathy
What is a plexus injury called?
Plexopathy
What is a peripheral nerve injury called?
Peripheral neuropathy
What is it called when one peripheral nerve is injured?
mononeuropathy
What is the most common type of nerve injury?
Peripheral neuropathy
What is the most common pattern of sensory loss in peripheral neuropathy?
Symmetrical distal sensory loss
What nerve is affected in wrist drop?
Radial nerve
What nerve is affected in foot drop?
Common peroneal nerve
What are the mechanisms behind peripheral nerve damage?
-Axonal loss
OR
-Demyelination
What does motor nerve conduction velocity tell us about the axon/myelin sheath?
The integrity of the myelin sheath
What does waveform tell us about the axon/myelin sheath?
The integrity of the axon
In a demyelinating injury what happens to the information travelling through the nerve?
It arrives asynchronously at different times
Name an acute demyelinating neuropathy
Guillain-Barre Syndrome
What are some key signs of Guillain-Barre Syndrome?
- Progressive paraplegia over days - 4 weeks
- Associated sensory symptoms proceeding weakness
- Pain very common
When do Guillain-Barre Syndrome symptoms peak?
10-14 days into onset of illness
How is Guillain-Barre Syndrome treated?
immunoglobulin infusion or plasma exchange
Name some chronic demyelinating neuropathies?
-CIDP (chronic inflammatory demyelinating polyradiculopathy)
-Hereditary sensory motor neuropathy
Name the types of axonal neuropathies?
-Idiopathic
-Vasculitic
-Paraneoplastic
-Infections
-Drugs/toxins
-Metabolic
How can peripheral axonal neuropathy be treated?
- Treat cause (e.g. Clearing Hep C)
- Symptomatic treatment (physio, analgesia etc.)
How can vasculitic peripheral axonal neuropathy be treated?
Pulsed IV Methylprednisolone + Cyclophosphamide
How can demyelinating (inflammatory neuropathy) peripheral neuropathy be treated?
- IVIg (immunoglobulin from donors)
- Steroids
- Azathioprine, Mycophenolate, Cyclophosphamide
What are the three types of peripheral neuropathy?
- Mononeuropathy
- Mononeuritis Multiplex
- (length dependent) peripheral neuropathy
