World Multiple Sclerosis Day 2024: Different types of this autoimmune disorder and their causes

The neurological symptoms of primary progressive multiple sclerosis (PPMS) progress continuously from the beginning without noticeable relapses or remissions. (Image: Canva)

World Multiple Sclerosis Day 2024: A complicated neurological disease that affects millions of individuals worldwide is multiple sclerosis (MS). It can take many different forms, but it is generally divided into two categories relapsing and progressive. The former have similar underlying causes, as the immune system misattacks the myelin sheath, which covers the nerve fibres in the central nervous system and provides protection. There is still much to learn about the precise causation of multiple sclerosis. Nonetheless, it's thought that people are predisposed to this illness by a mix of environmental and hereditary variables. It is essential to comprehend the various forms of MS in order to diagnose and treat patients effectively.

Relapsing-remitting multiple sclerosis (RRMS)

Of all the MS subtypes, relapsing-remitting MS (RRMS) accounts for about 85 percent of first diagnosis, says Dr Kamakshi Dhamija, senior consultant neurology, Max hospital, Vaishali. She says that relapses or flare ups well defined episodes of fresh or worsening neurological symptoms are its defining feature. Remissions, or periods of partial or whole recovery, occur after these relapses and are characterised by either improved or completely absent symptoms.

Causes: Although the precise origin of RRMS is unknown, a mix of environmental triggers and genetic predisposition is involved, says Dr Dhamija. Smoking, low vitamin D levels, and viral infections are examples of potential environmental influences. Due to the increased risk of MS in people with a family history of the disease, genetics also play a major influence.

Secondary progressive multiple sclerosis (SPMS)

Dr Dhamija says that some people with RRMS initially develop SPMS, or secondary progressive MS. The disease eventually reaches a stage where brain function gradually deteriorates and there are either few or no relapses. With this type of MS, the relapsing-remitting pattern gives way to a course that advances gradually.

Causes: Although the exact origins of SPMS are unknown, it is thought that the cumulative harm and nerve cell loss that take place throughout the relapsing phase are connected. While the exact causes of this progression are still unknown, persistent inflammation and neurodegeneration are believed to be important contributors.

Primary progressive multiple sclerosis (PPMS)

The neurological symptoms of primary progressive multiple sclerosis (PPMS) progress continuously from the beginning without noticeable relapses or remissions. About 10-15% of MS patients are diagnosed with PPMS, which typically manifests later than RRMS.

Causes: As with other forms of MS, the exact causes of PPMS are unknown, although a mix of environmental and genetic factors are thought to be involved. Studies imply that the fundamental causes of PPMS might be distinct from those of RRMS and SPMS, perhaps entailing more extensive nervous system damage, says Dr Dhamija.

Progressive-relapsing multiple sclerosis (PRMS)

One uncommon type of MS known as progressive-relapsing MS (PRMS) is marked by a gradual advancement of the illness from the start interspersed with sporadic acute relapses. People with PRMS, in contrast to those with SPMS, do not go through periods of remission; instead, their symptoms worsen on occasion.

Causes: Similar connections exist between immune system malfunction, genetic factors, and environmental impacts and the causes of PRMS. Research is currently ongoing to determine the precise pathophysiological distinctions between PRMS and other types of MS.