PERIPHERAL Neuropathies Flashcards
How different are the large nerve fibres from the small ones?
- Large fibres - more well myelinated
whereas the small nerve fibres are either THINLY myelinated or unmyelinated
What occurs with damage to the small sensory fibres?
- PAIN
- dysesthesia (UNPLEASANT sensation when touched)
- reduced pin prick and temperature sensation
Name the small sensory fibres.
- Adelta: thinly myelinated
- C: unmyelinated
What occurs with damage to the autonomic fibres?
- dizziness (d.t POSTURAL hypotension)
- impotence (ED)
- Nausea and vomiting (GASTROPARESIS)
- constipation/diarrhoea (esp. at night)
- bloating and belching
- tachycardia
- excessive sweating
- can’t empty bladder/ loss of bowel control
What are the symptoms of large sensory fibre damage?
- PARAESTHESIA
- unsteadiness
- numbness
- diminished vibration and JPS
- Reflexes may be lost
What occurs with large fibre motor damage?
PC:
- weakness/ unsteadiness/ wasting
SIGNS:
- REDUCED power
- absent reflexes
Name patterns of peripheral loss.
- glove and stocking
- mild/moderate/severe
- mononeuritis/ mononeuropathy
- radiculopathy
How may plexopathy occur?
- by traction of the nerve plexus
How are nerve damaged?
- axonal loss
- Peripheral nerve demyelination
Name an ACUTE demyelinating neuropathy.
- GBS (Guillaine Barre Syndrome)
- occurs within DAYS-wks
Name a chronic, progressive demyelinating neuropathy.
- CIDP (chronic inflammatory demyelinating polyradiculopathy)
- Hereditary sensory motor neuropathy (Charcot-Marie Tooth $)
How common is GBS?
1-2/ 100,000 per year
How does GBS present as?
- progressive paraplegia over days-4 weeks
- sensory symptoms precede weakness
- PAIN
- peak symptoms 10-14 days INTO onset of illness
When causes GBS?
- post-infectious CAMPYLOBACTER association
- campylobacter jejuni
WHat complications may arise from GBS?
- 25% require MECHANICAL ventilation
- 10% DIE mainly from autonomic failure (CARDIAC arrhythmia)
How is GBS treated?
- immunoglobulin infusion
AND/OR - PLASMA exchange
What is key about the pattern of muscle weakness in GBS?
- starts DISTALLY moves proximal
What is hereditary neuropathy?
- inherited
- NUMEROUS MUTATIONS (A.D, A.R and X-linked)
How may hereditary neuropathy present as?
- pure motor/ sensory/ sensorimotor/ small fibre and AUTONOMIC variants
What is the most common genetic mutation for GBS?
CMT1a
What is gr.1 of HMSN/ Charcot-Marie-Tooth?
- has SLOW nerve conduction velocities
- evidence of hypertrophic demyelinating neuropathy
What is usually seen with HMSN type 1?
- WEAKNESS and ATROPHY of lower legs in adolescence
- later WEAKNESS of HANDS
What is the type 2 HMSN variety characterised with?
- normal nerve conduction velocity
- axonal degenration
What are infectious causes of axonol neuropathy?
- HIV
- syphilis
- Lyme
- Hepatitis B and C
