Multiple sclerosis: causes, symptoms, treatment and complications
Multiple sclerosis (MS) is also known as encephalomyelitis or disseminated sclerosis. This disease affects 350, 000 people in the US and 2.5 million people worldwide. There is an insulating coat (myelin) meant to cover the nerve cells present in brain and spinal cord. It helps in the propagation of nerve impulses. Multiple sclerosis is actually an inflammatory disease in which myelin is damaged. Damage to myelin manifests itself in the form of variety of signs and symptoms that occur due to inability of parts of nervous system to communicate properly.
What is multiple sclerosis
Before we can move on to know about the causes and signs and symptoms of this disease, we first need to know how this disease progresses (pathophysiology of this disease). The exact pathophysiology of this disease is not yet fully understood. But it is believed that lesions and inflammation causes progressive damage to the nerve cells. Moreover, in the later stages there is an involvement of antibodies that start targeting body’s own tissues (nervous tissues in particular).
Multiple sclerosis literally means plaques or lesions (sclerae- lesion or plaque). In this disease there is loss of myelin synthesizing cells called oligodendrocytes. Moreover, due to disrupted blood brain barrier certain cells get entry into the brain. These cells are called T lymphocytes. Normally the blood brain barrier functions to keep these cells out of the brain, confined in the blood. But when the blood brain barrier disrupts, these cells get entry into the brain.
These cells are meant to cause inflammation. T lymphocytes recognize myelin as a foreign substance and trigger inflammation by causing release of several chemicals, mainly cytokines. These chemicals further damage already damaged brain nerve cells and signal other lymphocytes to move to the site of inflammation. This way the inflammation and damage to brain continues in a self driven manner.
Figure 1: Multiple sclerosis and demyelination
Causes of multiple sclerosis
The exact cause of multiple sclerosis is still unknown. But it is believed to occur due to a combination of environmental and genetic factors. Following are the most important causes of multiple sclerosis:
MS is more common in population that lives farther away from the equator but exceptions do exist. The relationship between geographical distribution and MS is not clear but several hypotheses have been suggested to explain this relation. According to one hypothesis, people living farther away from equator are less exposed to sunlight. This leads to decreased production of vitamin D, the production of which depends on exposure to sunlight. But how decreased vitamin D might cause MS is not known. Another hypothesis relates geographical distribution, season of birth of a baby and chances of multiple sclerosis. This hypothesis is based on an observation that incidence of MS are higher in people living close to northern hemisphere born in the month of May as compared to people born in the month of November. Geographical distribution and environmental factors, undoubtedly, have a relation with MS but how do these factors affect the progression of this disease is still poorly understood.
Although MS is not considered a hereditary disease, still there are a number of genetic factors and genetic variations that are likely to increase the chances of an individual getting this disease. Genetic factors associated with MS are:
- The chances of MS are significantly higher in the relatives of existing sufferers.
- The chances of MS are higher in identical twins. If one twin has this condition, there are 30% chances that the other twin also suffers from MS.
- Although MS is not hereditary but chances of kids getting this condition increase significantly if their parents suffer from MS. If both parents are affected, the chances of kids getting this condition increase 10 times.
- Genes that encode for the production of major histo-compatibility complex (MHC) are called human leukocyte antigen genes. These genes are present on the chromosome number 6. Variations in these genes are thought to contribute in the development and progression of MS.
There are two hypotheses in this regard, one is the hygiene hypothesis andother is prevalence hypothesis. According to hygiene hypothesis, excessively following hygienic guidelines decrease the exposure of an individual to certain microbes. This exposure is important because it triggers the development of immunity against severe infections. This might explain why MS is prevalent in European countries and not in third world countries. On the other hand, prevalence hypothesis states that heavy microbe burden in certain areas might increase the susceptibility of population living in that area to get the disease.
Many infections and infectious agents have been reported to act as triggers for multiple sclerosis but none of these triggers have yet been confirmed. Infectious agents that are suspected to cause MS in human beings include:
- Human herpes virus.
- Epstein Barr (HHV-4) virus.
- Viruses of mumps, measles and rubella.
Several miscellaneous factors have been associated with increased risk of MS. These factors include: o Smoking is an important risk factor MS. The prevalence of this disease is much higher in smokers as compared to non smokers.
- Stress might be a risk factor for MS.
- Eating certain type of diet or supplementation with hormones might trigger this condition. But there is still a need to establish a relationship between these two variables.
Signs and symptoms of multiple sclerosis
Since MS involves damage of nerves, it can affect a number of body structures and organs. The most important symptoms of MS pertain to autonomic, visual, sensory and motor systems. The exact symptoms would depend on the region of brain that is most affected by the disease. Some of the symptoms of multiple sclerosis include:
Since MS includes sensory system, it might present itself in the form of changed sensory modalities ranging from loss of sensitivity to the perception of abnormal sensations. Abnormal sensations associated with the damage of sensory system include:
- Sensation of body parts being pricked by pins and needles.
- Total loss of sensation in certain areas leading to numbness.
- Exaggeration of normal body reflexes.
Motor system problems
MS might affect motor system as well. A damage inflicted to motor system might present itself in the form of:
- Weakness of muscles.
- Spasm of muscles.
- Exaggeration of reflexes involving body muscles and tendons.
- Difficulty in movement.
- Difficulty in co-ordination (ataxia).
- Slurred speech.
- Difficulty in swallowing.
- Difficulty in defecation.
- Hampered urination.
Visual system problems
Another system that is commonly affected is visual system. MS affecting visual system would present itself in the form of following symptoms:
- Double vision.
- Optic neuritis (inflammation of optic nerve).
- Involuntary movements of eye (nystagmus).
In addition, there are some generalized symptoms of illness like:
- A feeling of being not well (malaise).
- Exhaustion and a feeling of being tired.
- Acute pain.
- Chronic pain in body parts.
Brain related issues
Since this disorder affects human brain, there might be some symptoms related to how human brain works. Such symptoms include:
- Difficulty in thinking.
- Difficulty in concentration.
- Mood swings.
The patients of MS show a unique phenomenon called “Uhthoff’s phenomenon”. In this phenomenon all the above mentioned signs and symptoms increase in frequency and intensity when the affected individual is exposed to temperatures higher than normal.
Another characteristic sign of this condition is “Lhermitte’s sign”. It is a sensation of an electrical current running down the spine as the patient bends his/her neck. This is a specific sign for MS. These symptoms may clinically present in two forms:
- In almost 85% cases, there is sudden worsening of all the symptoms. This condition lasts for a few days, weeks or months. It is eventually followed by a period of recovery.
- In the remaining 15% cases, there is gradual worsening of symptoms with no recovery phase. In most of the cases, the relapses of symptoms take place quite spontaneously without any warning. However, there are some things that should be noted in this regard:
- The relapse of symptoms takes place two times a year, in majority cases.
- Symptoms usually worsen during summer and spring season.
- Several infections increase the susceptibility of an individual to get the attacks. These infections include: common cold, influenza and gastrointestinal tract infections.
- The severity, duration and frequency of attacks increase with stress.
- Pregnancy seems to reduce the relapse of symptoms.
Complications of multiple sclerosis
MS affects nervous, so this disease can lead to a number of complications that might affect different parts of human body. Some possible complications of multiple sclerosis include:
Aches and pains
One of the most common complications of multiple sclerosis is body aches and pains. These pains might include:
- Back pain.
- Joint pain.
Multiple sclerosis increases the chances of several injuries including:
- Muscle strain.
- Joint damage.
This conditions serious affected one’s behavior and mental performance and can lead to:
- Poor performance in academic and social set ups.
- Poor concentration.
- Increase irritability.
- Increased chances of depression.
Vision and visual acuity is impaired leading to blurring and doubling of vision.
Urinary incontinence and complications of bowel movements are also very common.
Treatment options for Multiple sclerosis
Till date there is no known cure for multiple sclerosis. The only treatment available is symptomatic i.e. treating the symptoms disease. However, there are some therapies that have proven to be useful in the management of multiple sclerosis.
Management options during acute attacks
During acute attacks of multiple sclerosis, intravenous infusion of corticosteroids (like methyprednisone) is the usual course of treatment. Treatment with oral corticosteroids is another option for the management of acute attacks. Treatment of body aches and pain might be done with the use of pain relieving medicines or pain relieving techniques like massage.
Disease modifying treatments
There is no way to totally cure this condition. However, several medications have been approved by the regulatory agencies for relapsing-remitting multiple sclerosis (RRMS). Approved medicines are 8 in number including Interferone-1a, Interferone 1-bm Mitoxantrone, Glatiramer acetate, Nataizumab, Teriflunomide and Dimethyl fumarate.
The scheme for the usage of these medicines for controlling the progression of MS is as follows:
- The first line drugs for reducing the relapse of disease are Interferon and Glatiramer. These drugs have proved to reduce the recurrence of symptoms by 30%. Both these drugs are almost similar in these efficacy and clinical safety. The outcome of these medicines depends on when the therapy is started. If the therapy with Interferon and Glatiramer is started early in the disease, progression of disease can be significantly reduced.
- The second line of defense is commencing treatment with Natalizumab. Natalizumab is perhaps even more effective than first line drugs. It significantly reduces the progression of disease. However, it is also associated with serious side effects. That’s why treatment with Natalizumab is chosen as an option only in those cases that are refractory to the use of first line drugs. o Still another option of treatment is starting therapy with Mitoxantrone. Like Natalizumab, Mitoxantrone is associated with severe side effects. That’s why it is used only in those cases that are refractory to the use of first tow line of drugs.
Alternative treatment options
In addition to different medicines, several alternatives are usually suggested to cure multiple sclerosis. But none of these alternative methods is yet tested for its efficacy to cure multiple sclerosis. Alternative medicines for multiple sclerosis include: o As explained earlier, it is believed that deficiency of vitamin D is one of the basic culprits for the trigger of this disease. So, supplementing diet with vitamin D is a plausible treatment option. Some evidences do suggest the efficacy of this treatment option. o
Unproven methods for the treatment of multiple sclerosis include:
- Relaxation techniques like yoga and meditation to get rid of stress.
- Use of herbal medicines like herbal Cannabis indica.
- Hyperbaric oxygen therapy.
|Written by:||Michal Vilímovský (EN)|
|Education:||Medical student, 3rd Faculty of Medicine, Charles University, Prague, Czech Republic|
|Published:||February 23, 2014 7:43 AM|
|Next scheduled update:||February 23, 2016 7:43 AM|