Multiple sclerosis

Multiple sclerosis (MS) is an autoimmune disease resulting in damage to myelin which is the insulating covers of nerve cells in the brain and spinal cord.^[3] As a demyelinating disease, MS disrupts the nervous system's ability to transmit signals, resulting in a range of signs and symptoms, including physical, mental, and sometimes psychiatric problems.^[1][8][9] Symptoms include double vision, vision loss, eye pain, muscle weakness, and loss of sensation or coordination.^[3][10][11]

MS takes several forms of presentation:

• New symptoms can occur as an isolated attack; where the patient experiences neurological symptoms suddenly and then gets better (relapsing form) called relapsing- remitting MS which is seen in 85% of patients. ^[12]
• In other patients symptoms can slowly get worse over time (progressive form) called primarily progressive MS seen in 15% of patients. ^{[13][14] [12]}
• The patients with relapsing- remitting MS can experience gradual worsening of their symptoms following the attacks, this subtype is called secondary progressive MS.^[12] In relapsing forms of MS, symptoms may disappear completely between attacks, although some permanent neurological problems often remain, especially as the disease advances.^[14] In progressive forms of MS, the body's function slowly deteriorates once symptoms manifest and will steadily worsen if left untreated.^[15]
• A patient might have a single attack and not meet the full criteria for being diagnosed with MS this is called a clinically isolated syndrome.^[12]

While its cause is unclear, the underlying mechanism is thought to be due to either destruction by the immune system or inactivation of myelin-producing cells.^[4] Proposed causes for this include immune dysregulation, genetics, and environmental factors, such as viral infections.^{[16][17][8][18]} The McDonald criteria are a frequently updated set of guidelines used to establish an MS diagnosis.^[19]

There is no cure for MS.^[3] Current treatments aim to reduce inflammation and resulting symptoms from acute flares and prevent further attacks with disease-modifying medications, aiming at slowing prognosis and improving quality of life.^[8][20] Physical therapy^[7] and occupational therapy,^[21] along with patient-centered symptom management, can help with people's ability to function. The long-term outcome is difficult to predict; better outcomes are more often seen in women, those who develop the disease early in life, those with a relapsing course, and those who initially experienced few attacks.^[22]

New evidence suggests an important role of lifestyle factors in the prognosis of MS, where multiple lifestyle factors (including smoking, alcohol consumption, exercise, diet and vitamin D levels..) have been linked to affecting the EDSS score depending on patients' age, gender and disease duration. ^[23][24]

MS is the most common immune-mediated disorder affecting the central nervous system (CNS).^[25] In 2020, about 2.8 million people were affected by MS globally, with rates varying widely in different regions and among different populations.^[26] The disease usually begins between the ages of 20 and 50 ^[2]and is almost three times more common in females than in males (3:1 ratio).^[27]

MS was first described in 1868 by French neurologist Jean-Martin Charcot.^[28] The name "multiple sclerosis" is short for multiple cerebro-spinal sclerosis, which refers to the numerous glial scars (or sclerae – essentially plaques or lesions) that develop on the white matter of the brain and spinal cord.^[28]