Multiple sclerosis (MS) is defined as an inflammatory demyelinating disease characterised by the presence of episodic neurological dysfunction in at least two areas of the central nervous system (brain, spinal cord, and optic nerves) separated in time and space.

Pathophysiology

In early disease, re-myelination ******can occur and symptoms can resolve. In the later stages of the disease, re-myelination is incomplete and symptoms gradually become more permanent.

A variety of subtypes have been identified:

Relapsing-remitting disease

• most common form, accounts for around 85% of patients
• acute attacks (e.g. last 1-2 months) followed by periods of remission

Secondary progressive disease

• describes relapsing-remitting patients who have deteriorated and have developed neurological signs and symptoms between relapses
• around 65% of patients with relapsing-remitting disease go on to develop secondary progressive disease within 15 years of diagnosis
• gait and bladder disorders are generally seen

Primary progressive disease

• accounts for 10% of patients
• progressive deterioration from onset
• more common in older people

Risk factors:

• Female sex (Sx improve in pregnancy and postpartum)