Peripheral Neurology Flashcards
1
Q
What are the features of length-dependent axonal neuropathy?
A
- Causes include diabetes, alcohol, nutritional (i.e. folate/B12), immune mediated (i.e. RA) , drugs (i.e. amiodarone), infectious, inherited (Charcot-Marie-Tooth), paraneoplastic, neoplasic and critical illness
- Diffuse involvement of peripheral nerves, length dependent (starts in toes/feet), symmetrical, slowly progressive and weakness
2
Q
What are the features of Guillain-Barre syndrome?
A
- Post infectious autoimmune aetiology (e.g. campylobacter, CMV, EBV)
- Progressive (ascending weakness) over days
- Flaccid quadrapariesis with areflexia
- May have respiratory/bulbar/autonomic involvement
- Treated with IVIG, plasma exchange, VTE prophylaxis (PE leading cause of death) and supportive care
- CIDP is chronic form
- Brighton criteria used for diagnosis
3
Q
What are the clincial features of muscle disease?
A
- Proximal limb weakness (difficulty raising arms above head, arising from seated position)
- Facial weakness (characteristic myopathic facies, drooling)
- Eyes (ptosis, opthalmoplegia)
- Bulbar (dysarthria, dysphagia)
- Neck and spine (head drop, scoliosis)
- Respiratory (breathlessness – especially on lying flat)
- Myocardial (exercise intolerance, palpitations)
4
Q
What are the causes of muscular disease?
A
- Muscular dystrophies (dystrophinopathies, fascioscapulohymeral dystrophy, limb girdle, oculopharyngeal)
- Metabolic muscle disorders (glycogen storage diseases, defects of fatty acid metabolism)
- Mitochondrial disorders
- Myotonic disorders
- Inflammatory muscle disorders (polymyositis, dermatomyositis, inclusion body myositis)
- Neuromuscular junction disorders (Myasthenia gravis, Lambert Eaton syndrome)
5
Q
What is the pathogenesis of Myasthenia Gravis?
A
- Autoimmune disorder (antibodies to acetylcholine receptor at post synaptic NMJ)
- Association with other autoimmune disorders
- May be associated with thymic hyperplasia or thymoma
- Affects young women in 20s and older men in 70s
- Fatiguable weakness of ocular, bulbar, neck, respiratory and/or limb muscles
6
Q
How is Myasthenia Gravis diagnosed and treated?
A
- Antibodies to AChR present in 85% of cases
- Single fibre EMG and repetitive nerve stimulation also abnormal
- Managed with Pyridostigmine (anti-acetylcholine esterase) and immunosuppressive therapies (i.e. steroids and intravenous immunoglobulin)
7
Q
Mononeuritis multiplex
A
- Simultaneous or sequential development of neuropthy in 2 or more nerves
- Common causes include:
- DM
- Vasculitic (EGPA, polyarteritis nodosa)
- Rheumatological (RA, SLE, Sjogren’s syndrome)
- Infective (Hepatitis C, HIV)
- Sarcoidosis
- Lymphoma
- Management depends on underlying cause
8
Q
Length-dependent axonal neuropathy
A
- Diffuse involvement of peripheral nerves
- Age >50 years
- Length dependent - starts in toes/feet
- Symmetrical
- Slowly progressive
- No significant sensory ataxia
- Any weakness is distal and mild
- Causes inclued:
- DM
- Alcohol
- Nutritional (folate, B12, thiamine, B6 deficiency)
- Immune mediated (RA, SLE, vasculitis, polyarteritis nodosa)
- Metabolic/endocrine (renal failure, hypothyroidism)
- Drugs (Isoniazid, Cisplatin, Amiodarone, Gold)
- Infectious (HIV, hepatitis B/C)
- Inherited (Charcot-Marie-Toothm heriditary neuropathy with liability to pressure palsy)
- Neoplastic (myeloma)
- Paraneoplastic
- Critical illness
9
Q
Acute inflamatory demyelnating neuropathy - Guillain-Barre syndrome
A
- Post-infectious autoimmine aetiology (i.e. campylobacter, CMV, EBV)
- Progressive (ascending) weakness over days
- Flaccid quadraparesis with areflexia
- +/- respiratory/bulbar/autonimic involvement
- Treated with IVIG or apheresis
- CIDP - chronic form (steroid and IVIG responsive)
10
Q
Testing in neuropathy
A
- Bloods (neuropathy screen)
- Fasting gluocose/OGTT
- FBC
- U&Es
- LFTs
- TFTs
- B12/folate
- Protein electrophoresis
- LP
- May be useful in inflamatory/paraneoplastic
- Nerve conduction
- Lower peak in axonal loss (decreased amplitude)
- Delayed response in demyelinating
