Peripheral neuropathy

Question 1

What percentage of alcoholics have peripheral neuropathy per EMG findings?>

Answer 1

25-66%

Question 2

What is the natural history of peripheral neuropathy related to etoh?

Answer 2

Length dependent neuropathy

Initially pain, followed by increasing sensory loss then weakness

Question 3

What are the clinical features of B12 deficiency associated neuropathy?

Answer 3

Sudden onset
Concomitant involvement of upper and lower limbs at onset
Painless, sensory-dominant neuropathy with absent ankle jerk reflexes
Explained by concomitant myelopathy and peripheral neuropathy
MRI shoes hyperintense lesions in dorsal column
Associated with hyperpigmentation of knuckles

Question 4

What is more sensitive for assessment of paraproteins; serum protein electrophoresis or serum immunofixation electrophoresis?

Answer 4

serum immunofixation electrophoresis

Question 5

What is the most common cause of peripheral neuropathy?

Answer 5

Diabetic (followed by nutritional deficiency and alcohol)

Question 6

What are the metabolites of B12 that are recommended to be tested for in low-normal B12 levels?

Answer 6

MMA and homocystine

Question 7

What are the GBS variants?

Answer 7

Classic sensorimotor
Pure motor
Paraparetic (sensorimotor)
Bilateral facial palsy with paraesthesias
Pure sensory
Pharyngeal-cervical-brachial (sensorimotor)
Miller-fisher syndrome - eyes and cerebellar dysfunction
Bickerstaff brainstem encephalitis - CNS variant

Question 8

Negative symptoms of neuropathy

Answer 8

Motor: weakness
Sensory: numbness, sensory ataxia, inability to differentiate between hot and cold

Question 9

What does CIDP stand for?

Answer 9

Chronic inflammatory demyelinating polyradiculoneuropathy

Question 10

Approach to peripheral neuropathy

Answer 10

Time: onset, duration
Motor / sensory / both
Large / small fibre
Single nerve / multiple single nerves / polyneuropathy
Axonal process vs demyelination

Question 11

What is mononeuritis multiplex?

Answer 11

A mononeuropathy which happens in step-wise fashion (one nerve, then another)

Question 12

Autonomic symptoms of neuropathy

Answer 12

GI: bloating, early satiety, diarrhoea, constipation
GU: impotence, urinary incontinence
CV: postural dizziness, cold extremities, hyperhydrosis / anhydrosis

Question 13

Positive symptoms of neuropathy

Answer 13

Motor: cramps, twitching
Sensory: pain, paraesthesia, allodynia, hyperesthesia

Question 14

What is the prevalence of peripheral neuropathy?

Answer 14

2-8%

Question 15

What are the differences between demyelinating injury and axonal injury?

Answer 15

Demyelinating injuries:
inherited or inflammatory; can involve nerve roots / trunks resulting in proximal weakness, patchy involvement with rapid and complete recovery (in inflammatory causes)

Axonal injury:
Cause “dying back” of nerve distal to injury = “Wallerian degeneration”; often length dependent.

Question 16

Are motor or sensory neuropathies more common?

Answer 16

Sensory

Question 17

Are positive neuropathic sensory symptoms more or less common in inherited neuropathies?

Answer 17

less common

Question 18

Carpal tunnel syndrome

• cause
• exacerbating factors
• sensory pattern ?involves palm?

Answer 18

Entrapment of median nerve at the wrist between flexor tendons and flexor retinaculum
Results in pain and paraesthesias, usually worse at night or with use
Sensory loss spares palm

Question 19

What is Anti-Hu associated with?

Answer 19

Paraneoplastic neuropathy (sensory)

Question 20

Treatment for carpal tunnel

Answer 20

Carpal splint, steroids, surgical management

Question 21

What is albumino-cytologic dissociation?

Answer 21

In CSF: increased total protein concentration with normal total nucleated cell count. Seen in GBS.

Question 22

What is the typical presentation of CIDP?

Answer 22

symmetrical, motor-prodominant, proximal and distal, areflexic
relapsing or progressive >8 weeks

Question 23

What percentage of peripheral neuropathy remain cryptogenic following extensive work up?

Answer 23

20% remain cryptogenic