Multiple sclerosis (brief)

Question 1

How common is it?

Answer 1

Prevalence 6 per 10,000

Question 2

Who does it affect?

Answer 2

Begins in early adulthood and is more common in women.

Question 3

What causes it?

Answer 3

Multiple plaques of demyelination within the brain and spinal cord. These plaques are disseminated in both time and space, hence the old name ‘disseminated sclerosis’. Precise mechanism unknown, but there is an inflammatory process in the white matter in the brain and spinal cord mediated by B cells and CD4 cells. It is thought that exposure to a specific infectious agent in childhood, EBV, may predispose you later. Antibodies produced by B cells and T cells directed against EBV nuclear antigens may be redirected to attack CNS myelin because of molecular mimicry. Inflammation, demyelination and axonal loss are major features of MS.

Question 4

How does it present?

Answer 4

Typically, as a young adult with 2 or more clinically distinct episodes of CNS dysfunction followed by a remission here the symptoms or signs resolve to some extent over a couple of weeks. The regression of symptoms is attributed to the resolution of inflammatory oedema and to partial demyelination. 3 characteristic common presentations of relapsing and remitting MS are optic neuropathy, brainstem demyelination and spinal cord lesions.

Question 5

Investigations

Answer 5

MRI of brain and spinal cord is the definitive test.

Question 6

Treatment

Answer 6

Short courses of steroids. Subcutaneous administration of beta-interferon reduces the relapse rate by 1/3 in relapsing/remitting disease. Also, physio and there’s a few other drug options if you want to consider it.

Question 7

Conditions that would present similarly

Answer 7

Inflammatory disease such as Bechet’s disease, SLE, sarcoid. Mass or vascular lesions. A single lesion in the cord may produce paraparesis and a sensory level and mechanical cord compression must be excluded by MRI.