Multiple sclerosis is defined as a chronic, inflammatory demyelinating auto – immunological disease .The name multiple sclerosis refers to the scars ( sclerosis), known as plaques formed in the nervous system.
There are four types of MS classified according to the course/progression of the disease process.
Prevalence
According to government guidelines, MS is diagnosed in 3.5-6.6 people per 100000 of the population each year in England and Wales .
Age
MS is usually diagnosed between the age of 20and 50 years.
Gender
Approximately the ratio of women to men affected is 2:1.
Geography
MS occurs with much greater frequency in areas that are farther away from the equator
The definitive cause in unknown. However, the evidence suggests that the cause may be a combination of both genetic and environmental factors.
Viral infection
The evidence indicates that a viral infection, produce by a widespread microbe rather than a rare pathogen , could be the origin of the disease, for example human herpes virus , chicken pox and glandular fever
Vitamin D Deficiency
Vitamin D Deficiency has been linked with a higher risk of MS this may occur as a result inadequate intake of the vitamin, couple with a lack of exposure to sunlight and may explain the geographical distribution of MS in countries further away from the equator.
Genetic Factors
MS is not considered a hereditary disease. However, genetic may play a role in determining a person susceptibility to MS
Familial
The risk of acquiring MS is higher In relatives of a person with the disease than in the general population.
Pathology
Although the initial trigger is unknown, the damage to the nervous system in MS is believed to be the patient’s own immune system. Lesion most commonly involve the White matter of the central nervous system in a person of demyelination. The peripheral nervous system is rarely involved.
The process of demyelination results in a thinning or complete loss of myelin, and as the disease advances, the destruction of the nerve axons occurs. The nervous system depends crucially on the myelin sheath for insulation and support, and for fast nerve conduction. So, when the myelin sheath is lost, the neuron no longer conducts electrical signals effectively. Of course, with axon destruction, it is impossible for the neuron to conduct signals. The outcome of these processes means that communication between different parts of the central nervous system is slow, inaccurate, or non-functional.”
Multiple Sclerosis (MS) is an extremely variable condition. Signs and symptoms develop as the cumulative result of multiple lesions in the central nervous system. Sites of demyelination include the cerebral cortex, brain stem, spinal cord, basal ganglia, cerebellum, and cranial nerves. Understanding the function of these different areas of the brain will give the therapist a platform by which to reason through potential clinical presentations.
The signs and symptoms presented will be a complex array of:
Physical
Cognitive and Perceptual
Secondary Complications
