Neurological Disorders: Multiple Sclerosis (MS)

What is MS?

Multiple sclerosis is a neurological disease that affects the central nervous system (CNS) and presents usually with recurrent, or less commonly with a progressive neurological manifestations. CNS includes the brain and the spinal cord, and MS affects only the above two structures in the nervous system. A Neurologist is frequently involved in the care of these patients.

What causes MS?

It is still a mystery as to what causes MS, although the available evidences strongly point towards a multi-factorial influence including genetics & environmental (e.g. viral infections) factors. MS is not considered as a hereditary disease but genetics appear to play certain role.

Who gets Multiple Sclerosis?

There must be some environmental factors that are involved in the triggering of MS; this idea is based on the observation that MS has a predilection for people living nearer to the poles of the earth (cold & temperate zones) as compared to the equator (tropical) region. Although people from all over the world can acquire MS; but patients are obviously clustered in the non-tropical regions.

What exactly is MS?

Multiple Sclerosis is considered as a demyelinating type of disease as it damages myelin structure of the brain & spinal cord. Neurons, the nerve cells, dispatch the neural signals through their long thread like structure called axons. These axons are wrapped up by a substance called myelin and it considerably enhances the speed with which neural signals are transmitted from one place to another within the central nervous system. If the myelin insulation material gets damaged the neural signals are not conducted properly from one place to another and this will clinically manifest with varieties of neurological episodes.

How does patient present?

Patients can have symptoms and signs suggestive of the involvement of the brain and spinal cord. The optic nerve (second cranial nerve or the nerve of vision) is considered as continuation of brain so it may get involved too. The clinical manifestation would depend upon what area of brain or spinal cord is involved. MS attacks characteristically are disseminated in time & space, what it means is the episodes occur at different times and involve different areas of brain & spinal cord (of course this is not necessarily true for the progressive types of MS).

Some of the common manifestations of Multiple Sclerosis include;

  • Blurring or loss of vision in one eye (optic nerve inflammation)
  • Numb feeling or pins & needles of limb/limbs
  • Weakness (paralysis) of limb/limbs
  • Speech deficits
  • Facial droop (paralysis)
  • Double vision
  • Stiffness (spasticity and/or rigidity)
  • Urinary bladder symptoms like incontinence etc.

What are the types of MS?

The four types of MS are;

  • RRMS (relapsing & remitting)
  • SPMS (secondary progressive)
  • PPMS (primary progressive)
  • PRMS (progressive/relapsing)
Relapsing & remitting type is the commonest one and here patient experiences recurrent neurological deficits, however they gradually recover from them with almost no or only minimal residual deficits. Some of these relapsing & remitting type patients later in the course of their illness develop a progressive course which is called as SPMS. In the primary progressive type there usually are no discrete neurological episodes, rather it begins and progresses gradually until patients are severely handicapped. The PRMS patients’ begin with a PPMS course but later add on SPMS features.

In spite of lot of advance in the diagnosis & management, MS still continues to trouble lot of patients especially in the temperate & cold climate area.

Diagnosis

The diagnosis of MS is done based on characteristic clinical criteria that are supported by relevant investigations.

The following investigations are accomplished during the diagnosis of MS;

• Brain MRI scan
• CSF (cerebrospinal fluid) analysis – routine, oligoclonal bands, IgG Index, myelin basic protein etc
• Evoked potentials (visual, brainstem auditory, somatosensory)

Treatment

The acute attacks are treated with intravenous steroids (milder cases may be with oral steroids). If optic neuritis is present treatment should not be started with oral steroids.

For the long term therapy (preventive agents) the following are the usual options;

• Disease modifying agents: interferone beta, glatiramer acetate
• Immunosuppressive agents: Fingolimod (Gilenya), Nataliumab (Tysabri), Mitoxantrone (Novantrone ) etc.



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