Multiple Sclerosis is an autoimmune disorder that occurs in the Central nervous system of the body and leads to the destruction of the fatty protective substance called Myelin, which acts as an insulation for the nerve cells carrying the messages between the brain and rest of the body. Myelin facilitates the speedy and smooth transmission of nerve messages. The damage to the Myelin layer leads to slow and less efficient delivery of messages thereby causing relapses and increasing disability in the patients.
MS has impacted the lives of around 2.5 million people across the globe and in the US alone there are more than 4 lacs cases of MS. Women are twice more likely to be suffering from Multiple sclerosis as compared to men.
Multiple Sclerosis can be further classified into 4 different types based on the intensity of relapses and the time for disease progression.
Relapsing Remitting MS (RRMS)
This is the most common form of MS disease and around 85% of MS diagnosed patients are believed to be RRMS patients. The disease type is characterized by alternative occurrences of relapses and remissions. Relapses refer to the flare-up of MS symptoms which might include weakened vision, increased fatigue, problems in walking, increase in numbness or tingling sensation in different parts of the body. The relapse phase is typically followed by the remission phase referring to the absence of MS symptoms which might extend up to a year as well.
Secondary-Progressive MS (SPMS)
SPMS is the subsequent form of RRMS and around 50% of RRMS patients progress to SPMS in a 10 year time period. The presence of DMTs in RRMS delays the progression of disease from RRMS to SPMS in some of the patients but not necessarily would it prevent a patient to progress from RRMS to SPMS. SPMS is characterized by a continuous increase in disability and worsening of symptoms with or without the period of relapses and remissions. The patients might not have relapses at all but in SPMS the symptoms may not completely go off (plateau) in the remission period.
Primary Progressive MS (PPMS)
This disease type is somewhat less prevalent and around 10-15% of the MS patients are categorized as PPMS patients. Most of the PPMS patients do not have the relapses and remissions periods and the disease type is more characterized by the gradual worsening of symptoms or gradual increase in disability since the onset of the disease. Though there are no periods of relapses or remissions in this disease type in most of the patients, there might be plateau periods when the disease symptoms are stabilized. However, some of the PPMS patients might experience very rare relapses as well.
Progressive-Relapsing MS (PRMS)
PRMS is the rarest form of MS happening to only about 5% of the MS patients. PRMS patients incur steady disease progression and increase in disability from the onset of disease accompanied by acute relapses on the way to disease progression. There are no complete remission phases and the symptoms worsen as the time progresses and with the occurrence of multiple relapses.
Thus, MS can be classified into multiple types and all the different types of MS differ in the symptoms experienced by the patients and in the intensity of disease progression. Hence, it is important to accurately diagnose the type of Multiple Sclerosis in a patient and prescribe the therapy accordingly. Inaccurate diagnosis or delayed diagnosis of MS type in a patient might lead to suboptimal treatment outcomes and worsening of disease in the patients.