Multiple Sclerosis

Question 1

Definition

Answer 1

Inflammatory demyelinating disease of the CNS

Question 2

Types

Answer 2

o Relapsing-Remitting MS
• COMMONEST form
• Clinical attacks of demyelination with complete recovery in between attacks

o Clinically Isolated Syndrome
• Single clinical attack of demyelination
• The attack in itself does NOT count as MS
• 10-50% progress to develop MS

o Primary Progressive MS
• Steady accumulation of disability with NO relapsing-remitting pattern

o Marburg Variant
• Severe fulminant variant of MS leading to advanced disability or death
within weeks

Question 3

Aetiology

Answer 3

• UNKNOWN
• Autoimmune basis with potential environmental trigger in genetically susceptible individuals
• Immune-mediated damage to myelin sheaths results in impaired axonal conduction

Question 4

Risk factors

Answer 4

o EBV exposure

o Prenatal vitamin D levels

Question 5

Epidemiology

Answer 5

• UK prevalence: 1/1000
• 2 x as common in FEMALES
• Age of presentation: 20-40 yrs

Question 6

Presenting symptoms (commonest presenting symptom)

Answer 6

• Varies depending on the site of inflammation

• Optic Neuritis (COMMONEST)
o Unilateral deterioration of visual acuity and colour perception
o Pain on eye movement
o Common first symptoms of multiple sclerosis

Question 7

Presenting symptoms (sensory)

Answer 7

o Pins and needles
o Numbness
o Burning

Question 8

Presenting symptoms (motor)

Answer 8

o Limb weakness
o Spasms
o Stiffness
o Heaviness

Question 9

Presenting symptoms (autonomic)

Answer 9

o Urinary urgency
o Hesitancy
o Incontinence
o Impotence

Question 10

Presenting symptoms (psychological)

Answer 10

o Depression

o Psychosis

Question 11

Presenting symptoms (signs)

Answer 11

• Uhthoff’s Sign - worsening of neurological symptoms as the body gets overheated from hot weather, exercise, saunas, hot tubs etc.
• Lhermitte’s Sign - an electrical sensation that runs down the back and into the limbs when the neck is flexed

Question 12

Signs on physical examination (eyes)

Answer 12

• Optic Neuritis
o Impaired visual acuity (MOST COMMON)
o Loss of coloured vision

• Visual Field Testing
o Central scotoma (if optic nerve is affected)
• Scotoma = a blind spot in the normal visual field
o Field defects (if optic radiations are affected)

• Relative Afferent Pupillary Defect (RAPD)

• Internuclear Ophthalmoplegia
o Lateral horizontal gaze causes failure of adduction of the contralateral eye
o Indicates lesion of the contralateral medial longitudinal fasciculus

Question 13

Signs on physical examination (other)

Answer 13

• Sensory
o Paraesthesia

• Motor
o UMN signs

• Cerebellar
o Limb ataxia (intention tremor, past-pointing, dysmetria)
o Dysdiadochokinesia
o Ataxic wide-based gait
o Scanning speech

Question 14

Investigations

Answer 14

• Diagnosis is based on the finding of two or more CNS lesions with corresponding
symptoms, separated in time and space - McDONALD CRITERIA

• Lumbar Puncture
o Microscopy - exclude infection/inflammatory causes
o CSF electrophoresis shows unmatched oligoclonal bands

• MRI Brain, Cervical and Thoracic Spine (with gadolinium)
o Plaques can be identified
o Gadolinium enhancement shows active lesions

• Evoked Potentials
o Visual, auditory and somatosensory evoked potentials may show delayed conduction velocity