Peripheral Neuropathy

Question 1

What are the two categories of peripheral neuropathy?

Answer 1

Motor or sensory loss

Question 2

What is sensory peripheral neuropathy?

Answer 2

Damage to peripheral sensory nerves which results in symptoms such as weakness, numbness and pain

Question 3

What are the causes of sensory peripheral neuropathy?

Answer 3

ABCDE
Alcohol toxicity,
Vitamin B12 and/or folate deficiency,
Chronic renal failure,
Diabetes mellitus
Everything else - paraneoplastic syndrome and vasculitis

Question 4

What are the signs and symptoms of sensory peripheral neuropathy?

Answer 4

Usually length dependent so presents in glove and stocking distribution.
Large fibre involvement causes paresthesia and ataxia.
Small fibre involvement causes burning sensation, allodynia and hyperalgesia

Question 5

What are the investigations for sensory peripheral neuropathy?

Answer 5

Clinical evaluation,
Bloods: look for diabetes, B12 and folate,
Nerve conduction studies and electromyography (distinguishes peripheral neuropathy from other neurological disorders)
Imaging (MRI and CT)
Biopsy

Question 6

What is the management of sensory peripheral neuropathy?

Answer 6

Treat underlying cause,
Symptom management: NSAIDs, pregabalin or gabapentin.
Physical therapy: improves mobility
Lifestyle modifications

Question 7

What are the causes of motor peripheral neuropathy?

Answer 7

Guillain-Barre syndrome,
Polyphyria,
Lead poisoning,
Hereditary sensorimotor neuropathies (Charcot marie tooth)
Chronic inflammatory demyelinating polyneuropathy,
Diphtheria

Question 8

Why does alcohol excess cause neuropathy?

Answer 8

Direct toxic effects and it reduced absorption of B vitamins

Question 9

Describe features of Vitamin B12 neruopathy

Answer 9

Subacute combined degeneration of spinal cord which affects the dorsal column first (joint position and vibration)

Question 10

What are the features of charcot-Marie-Tooth syndrome

Answer 10

Motor loss which causes:
Foot drop,
High arches (pes cavus),
Hammer toes,
Distal muscle weakness,
Distal muscle atrophy,
Hyporeflexia,
Stork leg deformity

Question 11

What are the features of Guillain-Barre syndrome?

Answer 11

History of gastroenteritis.
Progressive symmetrical, ascending weakness of the limbs.
Respiratory muscle weakness,
Cranial nerve involvement (diplopia, bilateral facial nerve palsy, oropharyngeal weakness)
Autonomic involvement

Question 12

What are the investigations for Guillain-Barre syndrome?

Answer 12

Lumber puncture - raised protein but normal WCC.
Nerve conduction studies - Decreased motor nerve velocity, prolonged distal motor latency
Anti-GM1 antibodies

Question 13

What are the differential diagonsis for Guillain-Barre?

Answer 13

Polio (asymmetrical weakness from myelitis),
Lyme disease,
CMV,
HIV,
Transverse myelitis,
MG,
Spinal cord compression,
Porphyrias.
electrolyte derrangement
Brainstem strokes

Question 14

What are some varients of Guillain-Barre syndrome?

Answer 14

Paraparetic varient - Affecting lower limbs,
Miller fisher syndrome (anti-GQ1B antibodies, descending paralysis, opthalmoplegia)
Pure motor,
Bilateral facial palsy

Question 15

What is Guillian Barre Syndrome?

Answer 15

Post-infectious autoimmune disease which causes an acute inflammatory demyelinating neuropathy

Question 16

What are some potential causes of GBS?

Answer 16

Campylobacter jujuni, CMV, EBV

Question 17

What is the management of GBS?

Answer 17

IV Immunoglobulin over 5 days. Can use plasmapheresis but this has more side effects.
Regular monitoring of FVC,
VTE prophylaxis,

Question 18

What is mononeuritis multiplex?

Answer 18

Peripheral neuropathy characterised by involvement of individual, non-contiguous nerve trunks.
Presents with sensory and motor deficits in the distribution of specific peripheral nerves

Question 19

What are the clinical features of mononeuritis multiplex?

Answer 19

Numbness,
Weakness,
Pain,
Sicca symptoms,
Commonly affects peroneal, radial, axillary, median and sciatic nerve.

Question 20

What are the symptoms of neuropathy in common peroneal nerve?

Answer 20

Weak ankle dorsiflexion and sensory disturbance on lateral aspect of calf and foot.

Question 21

What are the symptoms of neuropathy in the radial nerve, axillary nerve?

Answer 21

Radial - Wrist/finger drop and sensory disturbance on dorsum of hand
axillary - Weakness of shoulder abduction

Question 22

What are the risk factors for mononeuritis multiplex?

Answer 22

Age > 50,
Vasculitis,
Diabetes
Sarcoidosis,
Hep C,
Hep B,
Connective tissue disease,
Livido reticualris
HIV

Question 23

What is the cause of mononeuritis multiplex?

Answer 23

Nerve ischaemia secondary to primary or secondary vasculitis.

Question 24

What are the investigations and treatment for mononeuritis multiplex?

Answer 24

EMG for every patient presenting with MNM.
Bloods,
Hepatitis antigens,
C-ANCA, P-ANCA, Rheumatoid factor, ANA, ds-DNA, serum ACE
Treatment - treat underlying cause

Question 25

Describe features of gastroparesis

Answer 25

It is GI autonomic neuropathy presenting with erratic blood sugars, bloating and vomiting. Management is with prokinetic drugs eg, metoclopramide

Question 26

What is the first line management of diabetic neuropathy?

Answer 26

amitriptyline, duloxetine, gabapentin or pregabalin