Multiple sclerosis (MS) is a degenerative disease that affects the central nervous system (CNS), characterised by inflammation, chronic autoimmune demyelination, and primary or secondary injury in axons. It usually occurs in ages between 20 and 40, mostly in women with different aspects. Clinically, it concepts variable neurological disabilities in vision and hearing organs, limb weakness or gait abnormalities, bladder dysfunction.
The great number of MS patients are mostly confronted with relapsing-remitting attacks or new or re-probable neurological outcomes. Types of MS can subdivide into four major groups regarding the signs and course of the disease.
In the light of the indicating clinical features, disease phases of MS have divided into four major groups. It is still in the dark whether these different phases express characteristic features of a specific disease or, also, whether some variants express different pathophysiologic mechanisms of different disease. Currently, the classifications are based on consensus and the clinical course of the disease.
Clinically Isolated Syndrome (CIS): Initial Phase
Since the clinical continuum of MS is extremely flexible, and eventually, some neurological abnormalities or disabilities may occur with time in those with MS. An acute or subacute neurological dysfunction associated with white-matter lesion is considered as clinical onset in 85 per cent of patients with MS. In this case, this is termed as a clinically isolated syndrome (CIS) characterised by demyelination in optic nerves, brainstem, or spinal cord.
Episodes must last for at least 24 hours in patients, and it is considered as MS characteristic feature but may not meet the fundamental standards to diagnose MS since whether CIS may or may not go on to develop MS. In this case, radiological scan techniques such as magnetic resonance image (MRI) are crucial.
As an example, the presence of classical demyelination lesions in MRI results from spinal cord and brain has defined as a most important determinant of the occurrence of a second relapse in CIS patients. However, CIS is not included in initiate phase MS markers. In the 2013 revision defining the certain criteria for MS, it is recommended that CIS should be enclosed in different phenotypes of MS .
Relapsing-Remitting MS (RRMS)
Relapsing-remitting or partial remitting is one of the most seen neurologic loss of function in a patient with MS. This neurologic loss can be occurred fast, constantly observed over couple hours, or worse, over days and weeks. Clinical outcomes of the disease can last days, weeks, and even months then may go on decreased degrees. Within early diagnosis, relapses (also known as exacerbation, bout or attack) can eliminate, but in time, it becomes harder to recover since the course of the disease progresses.
The frequency and the number of episodes vary considerably and have significant effects on the prognosis of the MS. If there are long gaps between attacks and speakable improvement is mentioned on, then it may be said that disease shows good progress in the level of recovery.
RRMS mostly shows itself in younger women population, fortunately, it may be possible to cure via acute anti-inflammatory agents such as steroids or immune-modifying therapies. It is foreseen that 85 per cent of MS patients had already RRMS and 80 per cent of them have observed secondary progressive MS (SPMS) development .
Secondary Progressive MS (SPMS)
Most RRMS patients later develop SPMS by age, and the rare or recurrent progressive disability characterises it. The most common progression for SPMS is an axonal loss. Unfortunately, there are no typical clinical criteria which allow clinicians to decide where it is converted from RRMS to SPMS. It is recommended that data come from clinical trials and patient’s own story with MS should be considered to determine the level of disease. As the disease progresses, the number of relapses increases and disability worsen, type of disease is termed as primary progressive multiple sclerosis.
Primary Progressive MS (PPMS)
PPMS (nearly 10 per cent portion in total individuals with MS) is characterised by recurrent, gradual or non-progressive recurrence from the onset and typically occurs in a population of men with myelopathy progressing with age. Patients with PPMS, even the disease symptoms occur over months to years, have no ability to remember the date of relapses.
Disease progression varies greatly:
Some patients experience significant disability for one to two years while others progress for more than several decades. Contrast to RRMS, individuals with PPMS are much older at their 40s to 60s. The most prominent and common progression is spinal cord dysfunction. PPMS differs from RRMS in terms of its pathophysiology.
Progressive-Relapsing MS (PRMS)
By five per cent of MS population, progressive relapsing MS (PRMS) is the least frequent version of MS by far, which has seen as progressive neuron dysfunction and different acute relapses from the beginning. Few information is available about the clinical features and prognosis of PRMS since it is observed in rare ratio. Most of the time, it is hard to distinguish PRMS from PPMS considering their similar clinical features and some specialist may use the same terminology for both types.