Demyelinating Pathologies

Question 1

MS phases

Answer 1

Preclinical (asymptomatic, may have lesions)
Relapse-remitting (episodic clinical disability, ≥1hr and ≥30days apart)
2° progressive (Not necessarily new lesions but progressive degeneration due to Wallerian degeneration)

1° progressive skips relapse-remitting phase

Question 2

MS pathology

Answer 2

Autoimmune demyelination of CNS disseminated in space and time with further damage from inflammatory plaques and axonal loss

Question 3

MS epidemiology

Answer 3

3x more common in females, mean age of onset 30
Approx. 50% concordance in monozygotic twins so part environmental part genetic
Increased incidence at greater latitudes potentially due to immunomodulatory effects of vit D

Question 4

MS presentation

Answer 4

Usually monosymptomatic, symptoms depend on area affected e.g. brain/brainstem/spinal cord
Symptoms may worsen with heat e.g. hot bath
Often corticospinal tract/bladder/optic neuritis

Question 5

MS diagnosis

Answer 5

Clinical diagnosis, McDonald criteria
MRI with contrast sensitive but not specific for plaque detection
LP may show oligoclonal Ab bands on electrophoresis, same Abs not present in serum

Question 6

McDonald criteria

Answer 6

≥2 attacks and ≥2 objective clinical lesions

≥2 attacks and 1 lesion and (MRI spatially disseminated lesions/+ve CSF/2nd attack at new site)

1 attack and ≥2 clinical lesions and dissemination in time (new lesion on repeat MRI after 3mths/2nd attack)

1 attack and 1 lesion and dissemination in time and dissemination in space (MRI/+ve CSF)

1° progressive MS and +ve CSF and dissemination in space/continued progression ≥ 1yr

Question 7

MS management

Answer 7

Lifestyle advice - exercise, stop smoking, low stress

DMDs
Dimethyl fumarate for mild/moderate relapsing-remitting
Alemtuzumab (acts against t-cells) and Natalizumab (against VLA-4 which allows immune cells to cross BBB) for relapsing-remitting

Relapse treatment - Methylprednisolone 1g/24h PO/IV for 3-5d shortens acute relapses

Symptom control
spasticity (baclofen/gabapentin/ benzo)
tremor (botox type A injection)
urgency (tolterodine/oxybutinin/ suprapubic catheterisation)
fatigue (amantadine/ CBT/ exercise)

Question 8

Devic’s syndrome

Answer 8

MS variant with transverse myelitis, lose motor/sensory /autonomic/ reflex/ sphincter function below level of lesion

Question 9

Lhermitte’s sign

Answer 9

Neck flexion causes ‘electric shocks’ in trunk/limbs

Question 10

Uhthoff’s phenomenon

Answer 10

Worsening of symptoms with heat e.g. hot bath

Question 11

Charles Bonnet syndrome

Answer 11

Rare, temporary blindness ± visual hallucinations

Question 12

Pulfrich effect

Answer 12

Unequal eye latencies so straight trajectories seem curved and distances misjudged side on

Question 13

Guillain Barre pathology

Answer 13

Autoimmune mediated demyelination of PNS often triggered by prior infection (e.g. campylobacter jejuni)

Question 14

Guillain Barre presentation

Answer 14

Weakness classically ascending but proximal muscles first
Mild sensory symptoms
Sometimes back pain initially
History of gastroenteritis

Question 15

Guillain Barre diagnosis

Answer 15

LP shows rise in protein

Nerve conduction studies

Question 16

Guillain Barre management

Answer 16

IVIg
Plasma exchange
Immunosuppressants e.g. methotrexate, azathioprine