Multiple sclerosis (MS) is type of an autoimmune disease which affects brain and spinal cord and causes degeneration of nerves of central nervous system. Nerves in the body have a covering on them which is called myelin whose function is for conduction of impulses and protecting nerves. In multiple sclerosis, there is inflammation which results in destruction of myelin because of which electrical impulses traveling along nerves slow down considerably and nerves become damaged. As this disease progresses, an individual starts having difficulty performing daily activities which are controlled by nervous system such as vision, speech, memory, walking, reading etc.
Classification and Types of Multiple Sclerosis (MS) or Disseminated Sclerosis
Patients usually have attacks or episodes of multiple sclerosis in which they experience a rapid deterioration in the normal physical abilities ranging from mild to severe. These episodes last from 24 hours to a few weeks. Multiple sclerosis is of four types depending on stage of disease.
- Relapsing-Remitting: This is manifested by relapse or flare-up of symptoms followed by recovery from symptoms. Symptoms can vary from being mild to acute, and relapses and remissions carry on for days to months. Majority of patients having MS start off with relapsing-remitting type.
- Secondary-Progressive: Patients who have relapsing-remitting MS develop this type. This is manifested by relapses and then partial recovery can occur but symptoms are still present between cycles and they progressively worsen leading to continuous progression of disability.
- Primary-Progressive: This type progresses gradually without remission and with continued symptoms.
- Progressive-Relapsing: This is very rare. Patients with this type of MS experience progressively worsening symptoms through period of remissions.
Pathophysiology of Multiple Sclerosis (MS) or Disseminated Sclerosis
Multiple Sclerosis is a type of an autoimmune condition. It is a disease caused due to malfunction of immune system which attacks the structures and tissues present in the human body because it fails to recognize them as its own and falsely recognizes them as foreign agents to the body system. Multiple sclerosis is characterized where the immune system attacks the nervous system. Multiple sclerosis is named such due to the lesions/plaques/ scars that occur in the nervous system. The majority of these lesions are present in the white area near the cerebellum, the spinal cord, the brain stem and the optical nerve causing hindrance in the transmission of impulses by the neurons. MS destroys the outer layer of the nerves i.e. myelin. There may be decrease or complete destruction of myelin causing inefficient transmission signals to the body. During the early stages of the disease, a partial restorative process called as remyelination occurs, but as the myelin cannot be completely rebuilt and because of recurrent attacks, it causes very less successful remyelinations. This in turn leads to formation of lesions in the irreversibly damaged areas.
Multiple sclerosis also causes inflammation due to the T-cells. These cells play a vital role in the body's defense mechanism. Due to inflammation, these T-cells permeate into the brain via the blood-brain barrier. Normally T-cells are not able to penetrate this barrier unless it is affected by a virus, which causes reduction in the strength of the connections forming the barrier. Due to this, the T-cells remain inside the brain, wrongly recognizing myelin as a foreign agent and attacking it. This causes an inflammatory response and other detrimental results like swelling and initiation of more immune cells and antibodies.
Etiology and Risk Factors for Multiple Sclerosis (MS) or Disseminated Sclerosis
MS is seen more in women as compared to men. MS is mostly common in ages between 25 and 45 but it can occur at any age. In MS, there is damage to myelin sheath. This is a protective covering surrounding nerve cells and when this is damaged nerve signals reduce or completely stop. MS causes inflammation resulting in nerve damage. This inflammation takes place when immune cells in the body attack nervous system. This can happen in any area of brain, optic nerve, or spinal cord. The exact cause of MS is unknown. The commonly thought cause is a virus or gene defect (or both). Environmental factors are also thought to be one of the reasons. Family history also increases the chances of getting MS. The attacks can occur or worsen due to fever, hot baths, sun exposure, or stress. In multiple sclerosis the body's own immune system attacks the nervous system. It is thought that a foreign agent like a virus changes the immune system causing the immune system to perceive myelin as an invader and attacking it. When the immune system attacks body's tissues, it is called autoimmunity. MS is a disease of the autoimmune system. Although remyelination occurs after the attack, it causes complete damage of the myelin in some nerves making them demyelinated. Scarring is also present in which there is accumulation of material leading to formation of plaques.
Signs and Symptoms of Multiple Sclerosis (MS) or Disseminated Sclerosis
Symptoms depend on the location and severity of the attacks. These attacks can last from days to months. There are periods of remissions in between the attacks. MS can relapse or get worse without periods of remission also. There is an increase in fatigue as the MS worsens. As the nerves can be damaged in any part of the brain or spinal cord, patients present with symptoms in various parts of the body.
- Muscle symptoms such as impaired balance/coordination, spasm in the muscles, numbness, abnormal sensations, difficulty moving extremities, difficulty in walking, tremors and weakness.
- Bowel and bladder symptoms such as constipation, leakage of stool, difficulty in urination, frequent urination, increased urge to urinate and incontinence.
- Eye symptoms such as double vision, discomfort in the eyes, uncontrollable eye movements and loss of vision.
- Brain and nerve symptoms such as decreased attention/concentration, impaired judgment, loss of memory, decreased reasoning power, depression, paranoia, dizziness and hearing loss.
- Sexual symptoms such as difficulty with erections, difficulty in vaginal lubrication.
- Speech and swallowing symptoms such as slurred speech, problem in chewing/ swallowing.
Investigations for Multiple Sclerosis (MS) or Disseminated Sclerosis
- A neurological examination is useful in finding out any abnormal reflexes, reduced ability in moving parts of body, reduced sensation and other defects of nervous system function.
- An ophthalmologic examination is useful in finding out aberrant pupil responses, alteration in eye movement, problems with visual acuity, rapid eye movement, and other problem with eyes.
- Lumbar puncture is done to include CSF oligoclonal banding to look for presence of antibodies.
- MRI of brain and spine helps in diagnosis of MS.
- Nerve function studies.
Treatment for Multiple Sclerosis (MS) or Disseminated Sclerosis
No frontline treatment for MS is found till date. There are many therapies that can be done to slow down disease process. Main aim of this treatment is decreasing symptoms and gives patient as much normal a life as possible, help in recovery from attacks along with reducing number of attacks and slowing down progression of MS.
Medications Used For Slowing the Progression of Multiple Sclerosis (MS) or Disseminated Sclerosis Are:
- Interferons like Avonex, glatiramer acetate like Copaxone, mitoxantrone like Novantrone, a new drug called Tysabri etc.
- Steroids help in decreasing the intensity of MS attacks.
- Drugs for controlling symptoms are: Baclofen, Zanaflex, or benzodiazepine to reduce muscle spasms.
- Cholinergic drugs for urinary issues.
- Antidepressant medications for improving mood and address other behavioral symptoms.
- Amantadine may be given for tiredness.
- Other treatment consists of PT, speech therapy, OT, etc.
- Exercise along with healthy lifestyle, adequate nutrition, and rest also helps in MS.
- Preventing stress, excessive temperatures and other illnesses.