Disorders of the PNS

Question 1

What is a nerve issue arising at the nerve root known as?

Answer 1

Radiculopathy/Ganglionopathy

Question 2

What is a nerve issue arising at a nerve plexus known as?

Answer 2

Plexopathy

Question 3

What are some forms of peripheral neuropathy?

Answer 3

Mononeuropathy - 1 nerve affected
Mononeuritis multiplex
Peripheral neuropathy (length dependant)

Question 5

Where is the most common entrapment site of the median nerve?

Answer 5

Carpal tunnel (Wrist)

Question 6

Where is the most common entrapment site of the ulnar nerve?

Answer 6

Cubital tunnel (Elbow)

Question 7

Where is the most common entrapment site of the radial nerve?

Answer 7

Spiral groove of humerus

Question 8

Where is the most common entrapment site of the posterior interosseous nerve?

Answer 8

Supinator muscle (Forearm)

Question 9

Where is the most common entrapment site of the lateral cutaneous nerve of thigh?

Answer 9

Inguinal ligament

Question 10

Where is the most common entrapment site of the common perineal nerve?

Answer 10

Neck of fibula

Question 11

Where is the most common entrapment site of the posterior tibial nerve?

Answer 11

Tarsal tunnel (Flexor retinaculum - foot)

Question 12

What is foot drop a sign of?

Answer 12

Disease or trauma affecting the common peroneal nerve

Question 14

What is mono neuritis multiplex?

Answer 14

A condition in which there is damage to 2 or more distinct nerve areas

Question 15

What peripheral nerve condition is shown?

Answer 15

Mononeuritis multiplex

Question 16

What are some conditions that can cause mononeuritis multiplex?

Answer 16

• Diabetes mellitus
• Leprosy
• Vasculitis, including eosinophilic granulomatosis with polyangiitis amyloidosis (most common cause)
• Malignancy
• Neurofibromatosis
• HIV and hepatitis C infection
• Multifocal motor neuropathy with conduction block

Question 17

What are some forms of polyneuropathy?

Answer 17

Hereditary sensory motor neuropathy
Guillain-Barré syndrome
Idiopathic
Metabolic
Toxic
Autonomic

Question 18

What is the old name for hereditary sensory motor neuropathy?

Answer 18

Charcot-Marie-Tooth disease

Question 19

What is HSMN?

Answer 19

Inherited disease that affects the peripheral motor and sensory nerves

Question 20

Describe the genetics of HSMN?

Answer 20

AD, AR, X-linked - hundreds of mutations, demyelinating and axonal varieties

Question 21

What is the common sub-type of HSMN?

Answer 21

HSMN Ia is the most common type (70%) - autosomal dominant demyelinating neuropathy

Question 22

What are some symptoms of HSMN?

Answer 22

Typical presenting symptom is weakness of the feet and ankle

Question 23

What are some signs of HSMN?

Answer 23

Absent tendon reflexes
Foot and ankle weakness
Bilateral foot drop
Muscle atrophy below knee (Stork leg)
Pes cavus
Hand muscle atrophy

Question 24

What are some investigations required in HSMN?

Answer 24

• Tests to exclude other causes of neuropathy e.g. bloods, serum and urine protein electrophoresis, muscle biopsy, CSF
• Genetic studies
• Nerve conduction studies

Question 25

How is HSMN managed?

Answer 25

No management Just support from MDT members

Question 26

What is Guillain-Barré syndrome?

Answer 26

An 'acute paralytic polyneuropathy' that affects the peripheral nervous system

Question 27

What are some bugs that can cause Guillain-Barré syndrome?

Answer 27

Campylobacter jejuni Cytomegalovirus Epstein-Barr virus

Question 28

Describe the pathophysiology of Guillain-Barré syndrome?

Answer 28

Infection leads to molecular mimicry: B-cells create antibodies against the pathogenic antigens, which also match those on the nerve cells, therefore targeting proteins on the myelin sheath or the axon

Question 29

How does Guillain-Barré syndrome present?

Answer 29

- 4 weeks post-infection - Symmetrical ascending weakness - Reduced reflexes - Peripheral loss of sensation - Neuropathic pain - Possible cranial nerve weakness

Question 29

How is Guillain-Barré syndrome diagnosed?

Answer 29

Clinical diagnosis - Nerve conduction studies - Lumbar puncture (Raised protein)

Question 30

How may patients with respiratory failure be managed in Guillain-Barré syndrome?

Answer 30

Intubation Ventilation Admission to the ICU

Question 30

What vitamin deficiencies can cause metabolic neuropathy?

Answer 30

B12 Folate Thiamine (B1)

Question 30

How is Guillain-Barré syndrome managed?

Answer 30

- IV Ig (1st) or plasma exchange (2nd) - Supportive care - VTE prophylaxis

Question 30

What are some causes of toxic neuropathy?

Answer 30

Alcohol Amiodarone Phenytoin Chemotherapy (Cisplatin/Vincristine)

Question 31

What are some possible causes of metabolic neuropathy?

Answer 31

- Diabetes - Uraemia - Hepatic and thyroid disease - Acute intermittent porphyria - Amyloidosis - Vitamin deficiency

Question 31

What is Wernicke-Korsakoff's syndrome?

Answer 31

Thiamine-responsive encephalopathy due to damage in the brainstem and its connections Usually caused by alcoholism

Question 32

When may neuropathy be seen in cancer?

Answer 32

Polyneuropathy as a paraneoplastic syndrome Myeloma Plasma cell dyscrias

Question 33

What are some systemic diseases that may cause vasculitic neuropathy?

Answer 33

SLE Polyarteritis nodosa Granulomatosis with eosinophilia Rheumatoid disease

Question 34

What are some symptoms of autonomic neuropathy?

Answer 34

Postural hypotension Urinary retention Erectile dysfunction Nocturnal diarrhoea Diminished sweating Impaired pupillary responses Cardiac arrhythmias

Question 35

What are some causes of chronic autonomic neuropathy?

Answer 35

Diabetes Amyloidosis Hereditary

Question 36

What are some causes of acute autonomic neuropathy?

Answer 36

Corticobulbar syndrome Porphyria

Question 37

How are peripheral neuropathies managed?

Answer 37

- Treat cause - Symptomatic treatment

Question 38

What are some symptomatic treatments of peripheral neuropathy?

Answer 38

Physiotherapy Orthotics Neuropathic pain relief

Question 39

How is vasculitis neuropathy managed?

Answer 39

Pulsed IV methylprednisolone + Cyclophosphamide