Multiple Sclerosis is a disease of the central nervous system (brain and spinal cord). Many nerve fibres within Demyelination the central nervous system are covered with an insulating layer of 'myelin' which helps them conduct electricity. Rapid conduction of electricity in the brain and spinal cord is required for proper function of the nervous system. In Multiple Sclerosis, inflammation causes damage to the myelin which leads to loss of function. This is called relapse.

The symptoms a patient experiences depends on which part of the brain or spinal cord the inflammation affects. Inflammation can reduce over time (sometimes with the aid of medical treatments) and the nervous system can repair itself to some extent. This is referred to as remission.

Over time, however, some patients may stop improving after relapses and may accumulate disability. This is referred to as disease progression. Disease progression is caused by damage to nerve fibres themselves. Some nerve fibres may dengenerate over time in the disease causing irreversible disability.

How is MS Diagnosed?

Multiple Sclerosis may be difficult to diagnose as there is no single test which can make the diagnosis. The diagnosis is based upon proper clinical assessment of the patient's symptoms (history) and a thorough examination of the nervous system by a neurologist. Usually patients will undergo a series of associated investigations in order to guide the clinician to the diagnosis.

These include:

MRI Scan
Often the brain and/or spinal cord will be imaged. MRI scans are very detailed brain scans which can detect evidence of inflammation within the nervous system.

Lumbar Puncture (LP)
This is often used to look for further evidence of an inflammatory response within the spinal fluid

Evoked Potentials
These are neuropsychological tests which can measure the speed of nerve impulses between areas of the brain. Slowing of conduction is a feature of Multiple Sclerosis

Several guidelines or criteria for diagnosis have been drawn up by panels of experts (e.g. McDonald criteria) but it may still often be difficult to make a definite diagnosis in the early stages of the disease.

Types of MS

Relapsing-Remitting MS (RRMS) is the most common form of the disease. It is characterized by clearly defined acute attacks with full recovery (1a) or with residual deficit upon recovery (1b). Periods between disease relapses are characterized by a lack of disease progression. Approximately 85% of people with MS begin with a relapsing-remitting course.

Figure 1a Figure 1b

Figure 1a Figure 1b

Primary Progressive MS (PPMS) PPMS is characterized by progression of disability from onset, without plateaus or remissions (2a) or with occasional plateaus and temporary minor improvements (2b). A person with PPMS, by definition, does not experience acute attacks. Of people with MS are diagnosed, only 10% have PPMS. In addition, the diagnostic criteria for PPMS are less secure than those for RRMS so that often the diagnosis is only made long after the onset of neurological symptoms and at a time when the person is already living with significant disability.

Figure 2a Figure 2b

Figure 2a Figure 2b

Secondary-Progressive MS (SPMS) SPMS begins with an initial relapsing-remitting disease course, followed by progression of disability (3a) that may include occasional relapses and minor remissions and plateaus (3b). Typically, secondary-progressive disease is characterized by: less recovery following attacks, persistently worsening functioning during and between attacks, and/or fewer and fewer attacks (or none at all) accompanied by progressive disability. According to some natural history studies, of the 85% who start with relapsing-remitting disease, more than 50% will develop SPMS within 10 years; 90% within 25 years. More recent natural history studies (perhaps because of the use of MRI to assist in the diagnosis) suggest a more benign outlook that these numbers suggest. Nevertheless, many patients with RRMS do develop SPMS ultimately.

Figure 3a Figure 3b

Benign MS If you have a small number of relapses followed by a complete recovery, you may be described as having benign MS. It is only possible to make a diagnosis of benign MS once you have experienced little or no disability for a period of 10 to 15 years. However, a diagnosis of benign MS does not guarantee that you will be free of problems; a relapse may occasionally occur after many years in which your MS has been inactive.

Key Facts About MS

Multiple Sclerosis is a common cause of disability in young people in the United Kingdom
The disease is more common in women than men and typically starts between the ages of 20 and 40
Approximately 120 people per 100,000 in England have the disease
In the Bristol and Avon region, the population of patients with Multiple Sclerosis is in the order of over 2,000
In the Bristol and Avon area alone, over 100 new cases of Multiple Sclerosis will develop each year
Of these, over 90 are likely to present with a relapsing-remitting course, but approximately 10 will exhibit a course of steady progression of disability from the onset (Primary Progressive Multiple Sclerosis)
As a chronic disease with disease duration typically of decades, long-term therapeutic and care strategies are require

World Distribution of MS

What is Multiple Sclerosis?

How is MS Diagnosed?

Types of MS