Peripheral neuropathy

Question 1

Describe the characteristics of the following types of nerve damage in terms of symptoms, power, sensation and reflexes:

• large motor fibre
• large sensory fibre
• Small fibre
• Autonomic

Answer 1

-weakness, unsteadiness, wasting
reduced
normal
absent

-numbness, parasthesia, unsteadiness
normal
vibration and JPS reduced
absent

-pain, Dysesthesia
normal
pin prick and temp reduced
present

-dizzines (postural hypotension), impotence, nausea and vomiting (gastroparesis)
normal
normal
present

Question 2

Name the different points at which nerve damage can occur?

Answer 2

Order is from spinal cord proximity outwards:
radiculopathy
Plexopathy
peripheral neuropathy (mononeuropathy, mononeuritis multiplex, length dependent)

Question 3

Describer the features of the types of peripheral neuropathy:
mononeuropathy
mononeuritis multiplex
length dependent

Answer 3

• effects a single nerve e.g. carpal tunnel
• multiple whole nerves taken out, asymmetrical, assoc with vasculitis
• symmetrical, effects the longest nerves from hands and feet up

Question 4

Describe the possible patterns of loss that occur with:

• length dependant?
• Mononeuritis/ Mononeuropathy?
• what investigation should be done?

Answer 4

-glove and stocking, mild-severe

-might get muscle wasting in thenar eminence
on neuritis: wrist and foot drop

-nerve conduction study

Question 5

What are the 2 ways in which nerves can be damaged?

-what would investigation show?

Answer 5

-Axonal loss
Peripheral nerve demyelination

-demyelinating= bizarre and jittery,

Question 6

demyelinating neuropathy

-types? (2) and causes of each types? (1,2)

Answer 6

-Acute
GBS(Guillaine Barre syndrome or AIDP)

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

Question 7

Guillan-Barre syndrome

• what is it?
• presentation?
• cause?
• treatment?

Answer 7

-progressive paraplegia over days up to 4 weeks
sensory symptoms proceed weakness

• acute, ascending and progressive neuropathy, characterised by weakness, paraesthesiae and hyporeflexia
• might be post infection e.g. campylobacter
• immunoglobulin infusion or plasma exchanges

Question 8

Hereditary neuropathy

• types? (6)
• inv?
• signs in type 1?

Answer 8

• motor, sensory, sensorimotor, small fibre, autonomic variants , congenital insensitivity to pain syndrome
• genetic testing for common mutations e.g. CMT1a

-foot deformity
champagne bottle wasting (of tibial muscle)

Question 9

Causes of axonal neuropathies?

• vasculitic? (2)
• paraneoplastic? (2)
• infections? (4)
• drug/toxin? (4)
• Metabolic? (5)

Answer 9

Idiopathic!!

• ANCA +ve, RA, sjogrens
• Myeloma, antibody mediated
• HIV, syphilis, Lyme, hepatitis
• Alcohol, amioderone, phenytoin, chemo
• DM, B12/folate def, Hypothyroidism, chronic uremia, pophyria

Question 10

Autonomic neuropathy:

-give the two types and their causes?

Answer 10

-Chronic
DM, Amyloidosis, hereditary

Acute
GBS, Porphyria

Question 11

Treatment of peripheral neuropathy:

• Axonal? (3)
• demyelinating? (3)

Answer 11

-Treat cause (i.e. clear hepatitis)
Symptomatic treatment (physio, orthotics, neuropathic pain relief)
Vasculitic- IV methylprednisolone + cyclophosphamide

-IVIg
steroids
azathioprine, mycophenalate, cyclophosphamide