Saturday, December 20, 2014

Multiple Sclerosis (MS)

Definition

Article updated and reviewed by Associate Professor of Medicine / Neurology, Cooper University Hospital & Robert Wood Johnson Medical School on May 11, 2005.

Multiple sclerosis (MS) is an inflammatory disease that attacks the myelin sheath which surrounds and protects nerve fibers of the brain and spinal cord (the central nervous system).

Description

The central nervous system contains billions of nerve cells which are joined by nerve fibers (axons). Electrical impulses originate in nerve cells and travel along the axons within the brain, spinal cord and peripheral nerves. Myelin is the substance that coats and protects the nerve fibers, similar to the way insulation shields electrical wires. In MS, the myelin sheath in the brain and spinal cord is attacked, becoming inflamed (swollen), and starts to break down bit by bit, then detaches itself from the nerve fibers.

Myelin gradually disappears and is replaced by cells that build up to form multiple hardened (sclerosed) patches of scar tissue (lesions) over the nerve fibers. When nerve impulses reach the damaged area, some impulses are blocked or delayed, causing the symptoms of MS. (see SYMPTOMS section for details).

The average age of patients diagnosed with MS is 30. The first symptoms of MS can occur as early as the age of 15 and rarely later than the sixth decade of life. The prognosis of MS is unpredictable and can vary significantly from patient to patient. Although the disorder is chronic and incurable, life expectancy can be normal or nearly so, with a life span of 35 or more years after diagnosis.

Typically, patients with MS experience episodes in which the disease becomes more active, called relapses. Each relapse causes increased symptoms. Sometimes, these relapses cause similar symptoms each time or they may cause very different symptoms that vary from relapse to relapse. Patients with this form of MS are said to have “relapsing-remitting” MS. Although patients may recover from each relapse, recovery may be incomplete, leaving patients with some residual, permanent symptoms. A great concern for patients with MS is the accumulation of residual symptoms from each attack, which over time leads to progressive disability. Patients who continue to have relapses with worsening residual symptoms each time are said to have “secondary progression”.

Other MS patients do not experience obvious attacks, but develop slowly progressive and worsening symptoms over time. This form of MS is called “primary progressive MS”. Patients with this form of MS have quite varied degrees of worsening, with some experiencing significant disability over only a few months, while others may worsen very slowly over years.

Causes

Although the exact cause of MS is unknown, researchers believe that MS is caused by a person's immune system attacking myelin in the brain and spinal cord. This abnormal immune response may be triggered by a combination of genetics and environmentally based factors (such as viral infections), which are not yet delineated.

Women are affected at least twice as often as men, and it is more common in persons of Northern European heritage and those living furthest from the equator. The cause of MS is not known.

Symptoms

The symptoms of MS include:

  • Tingling sensations of the extremities
  • Numbness of the extremities
  • Dizziness
  • Uncontrollable tremors
  • Slurred speech
  • Blurred or double vision
  • Loss of vision in one or both eyes
  • Walking/gait abnormalities
  • Hearing loss
  • Muscle weakness
  • Poor coordination
  • Unusual fatigue
  • Muscle cramps
  • Spasms
  • Problems with bladder, bowel and sexual function
  • Paralysis
  • Forgetfulness
  • Confusion

Note:

  • Symptoms vary, depending on where the MS occurs in the central nervous system.
  • Symptoms vary from person to person and from time to time in the same person.
  • Symptoms tend to appear, remit and reappear. There is no way at present to predict when or even if attacks of the disease will recur. In general, the typical pattern of MS is marked by periods of active disease, called exacerbations, and symptom-free periods, called remissions.
  • Symptoms may occur in any combination and can vary from mild to very severe.
  • Symptoms may worsen with increased temperature (such as with fevers or in a warm bath or shower).

Diagnosis

Doctors diagnose MS based on symptoms and medical history, a full neurological examination and laboratory tests to exclude other conditions that may mimic MS. Two factors must be clearly shown to establish the diagnosis of MS: (1) there must be clinical and laboratory-supported evidence of one or more lesions in different parts of the central nervous system, and (2) there must have been at least two separate exacerbations of the disease. Confirmation of these factors may take years because of MS exacerbations/remissions cycles and vagueness of early symptoms.

Medical History

The doctor will ask about the symptoms, how often the patient is experiencing them, how long the patient has been experiencing them (in time) and other past medical illnesses or operations, family history and personal habits.

Neurological Examination

The neurological examination includes testing:

  • mental and language functions (remembering dates, names and places)
  • movement/coordination skills
  • vision abilities
  • sensation
  • reflexes

Laboratory Tests

If the patient is suspected of having MS, a number of laboratory procedures may help to confirm it, including blood tests, magnetic resonance imaging (MRI), spinal tap and evoked potentials (EP) studies.

Blood work may be ordered to exclude other causes for the neurologic symptoms, such as Lyme disease, collagen-vascular diseases, AIDS and certain rare hereditary diseases.

An MRI uses computers and a strong magnetic field to produce pictures of the brain that make it possible to visualize and count lesions in the white matter (the part of the brain that contains myelinated nerve fibers) of the brain.

EP studies show the slowing of nerve impulses (messages) in the various parts of the central nervous system. Some of the EP studies are visual evoked potentials (VEP), brainstem auditory evoked potentials (BAEP), and somatosensory evoked potentials (SSEP). For these studies, electrodes are placed on the scalp, and the body systems being evaluated are stimulated (evoked) in various ways so the electrical reaction produced in the central nervous system can be recorded.

A spinal tap (“Lumbar puncture”) may be necessary to exclude some infections (such as Lyme disease) and to confirm inflammation in the nervous system, particularly when the diagnosis is uncertain. To extract the fluid, the doctor will insert a hollow needle into the lower part of the spinal canal and withdraw a small amount of cerebrospinal fluid (a watery liquid that surrounds the brain and the spinal cord). This fluid is then checked for the presence of increased levels of inflammatory cells, protein, oligoclonal bands, gamma globulin or myelin basic protein.

Treatment

Currently, there is no prevention or cure for MS; however, there are medications available to lessen the severity and frequency of MS attacks and treat many of the symptoms.

Muscle stiffness and weakness may be aided by physical therapy. Exercise can help preserve strength and function. Patients with difficulty walking or transferring may benefit from the use of assistive devices such as canes, walkers, or wheelchairs. After each attack, therapy is often needed to restore function optimally.

Avoidance of over-exhaustion, emotional stress, and a rise in body temperature (from a hot bath or hot and humid weather, for example) may reduce the symptoms of MS. Patients should follow a well-balanced, nutritionally sound diet and maintain a desirable weight, especially in those with limited exercise capacity.

When a patient experiences an acute MS attack (relapse), intravenous steroids are often used to help patients recover more quickly. Other related drugs (such as oral steroids and ACTH) are being used less frequently, but may be more effective in certain patients. Steroids suppress the immune system and may reduce the inflammatory attack on nerve cells in the brain.

In patients with relapsing-remitting MS, the use of interferons (Avonex, Betaseron, Rebif) and glatiramer acetate (Copaxone) may reduce the frequency of attacks as well as progressive disability from these attacks. In some circumstances, a chemotherapy agent, mitoxantrone (Novantrone) may be required. The exact mechanism of interferons and glatiramer acetate are not completely understood. However, it is believed that these agents alter the immune system and prevent some inflammatory cells from leaving blood vessels to enter the brain or spinal cord.

Other treatment is aimed at reducing the symptoms of MS such as pain, weakness, stiffness (spasticity), fatigue, and bladder, bowel, or sexual dysfunction.

Pain and tingling sensations may be controlled with simple analgesics. In some patients, sensory symptoms are better controlled with anti-depressants or anti-convulsants.

To treat spasticity, medications such as Lioresal (Baclofen), dantrolene (Dantrium), diazepam, tizanadine (Zanaflex) and clonazepam (Klonopin) have proven effective. Injections of botulinum toxin may be helpful, especially for patients with focal areas of spasticity. In severe spasticity, medications may be delivered directly into the spinal fluid by a pump implanted under the skin.

To treat fatigue, medications such as pemoline (Cylert), amantadine (Symmetrel) and modafanil (Provigil) may help. Other patients with coexisting depression may also be helped by the use of antidepressants.

As patients with bladder dysfunction may be susceptible to urinary tract infections, a Urological evaluation may be needed. Some patients may need medications to reduce bladder spasms, while others may need to catheterize themselves to assist in emptying their bladder and in preventing complications.

Questions

What medications are appropriate to prevent further attacks or worsening?

Will the disease progress?

What is the prognosis in this case?

Can I do anything to lessen the progression of the disease?

Are there any warning signs to an attack?

Are there any medications to treat the symptoms of MS?

If so, what are they and what are the side effects?

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Editorial review provided by VeriMed Healthcare Network.

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