Demyelinating Disorders & Peripheral Neuropathy

Question 1

What are the risk factors for Guillain-Barré syndrome?

Answer 1

Antecedent infection, classically Campylobacter jejuni (30% of cases), but also including influenza, HIV and Zola.

Question 2

What is the management for non ambulatory patients with Guillain-Barre Syndrome?

Answer 2

Intravenous immunoglobulin 2g/kg over 2-5 days OR

Plasmapheresis (PLEX)

Question 3

Based on bedside spirometry, when would you electively intubate a patient with Guillain-Barre Syndrome?

Answer 3

The “20-30-40” Rule

Elective intubation if:
Functional Vital Capacity < 20 mL/kg
Maximal Inspiratory Pressure (MIP) 0 to -30 cm H2O
Maximal Expiratory Pressure < 40 cm H2O

Question 4

What are the features of dysautonomia in Guillain-Barre Syndrome(6)?

Answer 4

70% of GBS patients have dysautonomia, including the following features (6):

(1) Paroxysmal Hypertension
(2) Orthostatic Hypotension
(3) Sinus Tachycardia
(4) Bradycardia, AV Block
(5) Urinary Retention
(6) Ileus

Question 5

What do EMG/NCS demonstrate in Guillain-Barre Syndrome?

Answer 5

Absent F waves & conduction blocks.

Question 6

What is Miller Fisher Syndrome?

Answer 6

A variant of Guillain-Barre Syndrome characterized by opthalmoplegia, ataxia and areflexia. Some develop dilated, fixed pupils and 1/4 will present with lower extremity weakness linking the disorder to GBS.

Question 7

What antibodies are associated with Miller Fisher Syndrome?

Answer 7

Anti-Gq1b antibodies

Question 8

What does the lumbar puncture demonstrate in Guillain-Barre Syndrome?

Answer 8

Albuminocytologic dissociation, meaning elevated protein and low white blood cells (< 5).

Typical seen in about 50% of patients in the 1st week of symptoms, and 75% by the 3rd week.

Question 9

What would you expect an MRI whole-spine with gadolinium to show in a case of Guillain-Barre Syndrome?

Answer 9

You may seen nerve root and cauda equina enhancement. The MRI will also allow you to rule out an acute myelopathy (a mimic of GBS).

Question 10

What proportion of patients with Guillain-Barre Syndrome progress to chronic inflammatory demyelinating polyradiculoneuropathy?

Answer 10

5%

Question 11

What are the clinical features of chronic inflammatory demyelinating polyradiculoneuropathy (CIPD)?

Answer 11

Progressive, symmetrical proximal AND distal weakness, with large fibre sensory loss, areflexia and fatigue over time.

Usually spares the cranial nerves, autonomic system and respiratory muscles.

Question 12

What is the prognosis of chronic inflammatory demyelinating polyradiculoneuropathy (CIPD)?

Answer 12

25% completely remit
50% assistive gait device
10% permanently disabled

Question 13

How do you treat chronic inflammatory demyelinating polyradiculoneuropathy (CIPD)?

Answer 13

Maintenance IVIG 1g/kg q3 weeks or SC Ig

Prednisone 1 mg/kg

Question 14

What is a clinically isolate syndrome?

Answer 14

A monophonic clinical episode of acute or subacute onset, with patient reported symptoms and objective findings typical of multiple sclerosis reflecting a focal or multi focal inflammatory demyelinating event in the CNS, with or without recovery and in the absence of fever or infection.

Question 15

What proportion of individuals will progress from a clinically isolated syndrome to multiple sclerosis?

Answer 15

If MRI lesions present -> 70%

If no MRI lesions -> 20%

Question 16

What are the 3 classic syndromes of multiple sclerosis?

Answer 16

(1) Optic Neuritis
(2) Brainstem/Cerebellar Syndrome
(3) Incomplete Transverse Myelitis

Question 17

What is the Uhthoff phenomenon?

Answer 17

Classically seen in multiple sclerosis, where symptoms are exacerbated by heat (ex. Showering)

Question 18

What is the typical picture of optic neuritis in multiple sclerosis?

Answer 18

(1) Painful eye movement
(2) Monocular vision and colour loss or scotoma.
(3) RAPD
(4) Mild disc swelling

Question 19

What are the typical brainstem/cerebellar syndrome features seen in multiple sclerosis (8)?

Answer 19

(1) Bilateral INO
(2) Diplopia
(3) Dysarthria
(4) Ataxia
(5) Gaze evoked nystagmus
(6) Vertigo
(7) Facial numbness
(8) CN6 Palsy

Question 20

What are the features of incomplete transverse myelitis that can be seen in multiple sclerosis (5)?

Answer 20

(1) Sensory Loss
(2) Asymmetric Limb Weakness
(3) Urge Incontinence
(4) Erectile Dysfunction
(5) Lhermitte Sign

Question 21

What is Lhermitte sign?

Answer 21

Spinal electric shock sensation with neck flexion, classically seen in transverse myelitis.

Question 22

What is the classic presenting clinical picture of neuromyelitis optica?

Answer 22

Acute attacks of bilateral or rapidly sequential optic neuritis (severe visual loss) OR transverse myelitis (often with limb weakness, sensory loss and bladder dysfunction), with a relapsing course.

Other suggestive symptoms includes intractable nausea, vomiting, hiccups and excessive daytime somnolence or narcolepsy due to medullary involvement.

Question 23

How can you differentiate neuromyelitis optica from multiple sclerosis?

Answer 23

Individual attacks of optic neuritis in NMO are indistinguishable from multiple sclerosis, though classically visual loss is more severe with NMO and sequential optic neuritis in rapid succession or bilateral simultaneous optic neuritis is highly suggestive of NMO. With transverse myelitis, NMO typically has a longer extent of spinal chord involvement and is often symmetric & severe, whereas MS is often incomplete and asymmetric.

Question 24

What are the revised Macdonald criteria for relapsing-remitting multiple sclerosis (3)?

Answer 24

(1) Multiple sclerosis is the most likely diagnosis AND
(2) At least 1 clinical attack AND
(3) Evidence of dissemination in space AND in time.

Question 25

What are the criteria for dissemination in time for multiple sclerosis (4)?

Answer 25

Dissemination in time requires:

(1) At least 2 clinical attacks OR
(2) An MRI with gadolinium enhancing AND non-enhancing lesions OR
(3) 2 MRIs with new T2 or gadolinium lesions on follow up scan OR
(4) CSF-specific oligoclonal bands

Question 26

What qualifies as dissemination in space for the revised Macdonald criteria in relapsing-remitting multiple sclerosis?

Answer 26

(1) At least 2 clinical attacks OR

(2) At least 2 lesions in at least 2 of cortical/juxtacortical, periventricular, infrantentorial or spinal cord.

Question 27

What benefits do corticosteroids have in the treatment of multiple sclerosis attacks?

Answer 27

If the attack is functionally disabling, high dose corticosteroids can speed recovery, but do not alter the degree of recovery or reduce the risk of future attacks.

Question 28

How would you treat an acute, disabling attack of multiple sclerosis?

Answer 28

Methylprednisolone 1000 mg IV daily for 3-7 days, followed by taper.

Consider PLEX if poor response to steroids.

Question 29

What are the home NIV criteria for individuals with ALS (6)?

Answer 29

(1) Symptoms - Orthopnea
(2) SNIP < 40 or MIP < 40
(3) Upright FVC < 65%
(4) FVC sitting or supine < 80% with symptoms or signs of respiratory insufficiency.
(5) Daytime hypercapnia pCO2 > 45
(6) Abnormal nocturnal oximetry or symptomatic sleep disordered breathing

Question 30

What is the medication that has shown increased survival in patients with ALS?

Answer 30

Riluzole