Pediatric Multiple Sclerosis

Pediatric Multiple Sclerosis - Causes, Symptoms, Diagnosis and Treatment

What is Pediatric Multiple Sclerosis?

Childhood MS may represent up to 10% of all MS cases. Establishing the diagnosis of MS in a child is complicated by the limited diagnostic criteria and the possibility of significant clinical and magnetic resonance imaging (MRI) overlap with acute disseminated encephalomyelitis and other pediatric diseases.

Although the clinical profile of MS appears similar to that seen in adults, several features may differ and specific issues arise in children. Sex ratios are different between young children with MS and adolescents -- implicating a role for sex hormones in disease pathogenesis and/or modification of disease expression. Younger patients with MS are more likely than adults to have seizures, brainstem, and cerebellar symptoms. Children with MS may have fewer T2 hyperintense areas on MRI scans, therefore not meeting MRI criteria established for adults. It is possible that the pediatric MS course is more indolent than in adult patients, but the disease may lead to significant disability at a younger age, e.g., while patients are students, young professionals, or want to start a family.

There has been no controlled clinical trial in children with disease modifying therapies approved for adult MS due to the limited number of patients under the age of 18 years compared with the adult contingent. As a result, children are receiving adult therapies in an arbitrary manner and our understanding of pediatric treatment effect and tolerability is limited. Available data on tolerability of approved drugs for adults is reviewed.

Causes and Risk Factors

There has been extensive research about MS over the past 50 years. While we still do not know the cause of MS, we know that it is an inflammatory disorder of the central nervous system that occurs in people with a tendency to such a problem. We know that about 350,000 people in the United States have MS, about one in a 1,000 people. We know that it is more common further north and south of the equator, though we are still unsure why this is. Females tend to get MS about three times as often as males, a rate which is similar to other immune diseases. In children this ratio may be even higher, with most of the patients being female. Girls with MS are more likely to have initial sensory symptoms (e.g. numbness and tingling) than boys. In addition, girls tend to recover more from their initial episode of MS than boys. MS is more common in Caucasians, but can occur in other populations. It is not contagious nor is it infectious. There may be a link with reduced vitamin D levels and perhaps with decreased sun exposure. In children with MS there may be an increased link with exposure to Epstein-Barr Virus. Most people with MS are diagnosed after the age of 18. Only about 3-5% of all MS patients have the symptoms of their MS begin in childhood.

We know that there is a genetic component to MS. Having a mother or father with MS increases the risk of having MS to about 3-5% lifetime, and having an identical twin with MS increases the risk to about 30%. However, many people with MS have no close family members with the disease.

There is nothing that an individual with MS either did to cause the disease to happen, or can avoid to stop the disease from following its natural course. We know that emotional stress may increase the symptoms of MS. We also know that attacks of MS are more likely after infections. There does not seem to be any association with physical trauma or surgical procedures and MS, nor do these seem to make MS worse.

Symptoms of MS

Pediatric MS is similar to adult MS in the kinds of symptoms that occur. MS varies from person to person so there is no ?standard? set of symptoms for MS. However we know that common symptoms of MS include numbness or tingling in various parts of the body, weakness of one or more parts of the body, walking difficulties, dizziness, fatigue, visual blurring, and occasionally double vision.

Patients may also have a symptom called Lhermitte?s phenomenon, in which they feel electrical tingling or shocks down their back, arms or legs when they bend their neck forwards. Sometimes people notice hesitancy when they try to urinate or may find that ?when they have to go, they have to go?. There is no way to predict which symptoms one person might develop. The usual course of MS is to have periods of time where things are relatively stable, followed by times when, over a few days or weeks, new symptoms occur or old symptoms worsen. This relatively rapid worsening is known as an exacerbation (also known as an attack, or a relapse). In others with MS, there may be a tendency to progress in that symptoms gradually worsen over time (months to years).

The symptoms of MS are erratic. They may be mild or severe, of long duration or short. They may appear in various combinations, depending on the area of the nervous system affected. The following are the most common symptoms of MS. However, each individual may experience symptoms differently. Symptoms may include:

  • Initial symptoms of MS
    The following are often initial symptoms of MS:

    • Burred or double vision

    • Red-green color distortion

    • Pain and loss of vision due to optic neuritis, an inflammation of the optic nerve

    • Difficulty walking

    • Paresthesia. This refers to an abnormal sensation, or pain, such as numbness, prickling, or "pins and needles."

  • Other symptoms of multiple sclerosis
    Throughout the course of the illness, an individual may experience any or all of the following symptoms, to a varying degree:

    • Muscle weakness in the extremities

    • Difficulty with coordination. Impaired walking or standing may result; partial or complete paralysis is possible.

    • Spasticity. The involuntary increased tone of muscles leading to stiffness and spasms.

    • Fatigue. This may be triggered by physical activity, but may subside with rest; constant, persistent fatigue is possible.

    • Loss of sensation

    • Speech impediments

    • Tremor

    • Dizziness

    • Hearing loss

    • Bowel and bladder disturbances

    • Depression

    • Changes in sexual function

    Approximately 50 percent of all people with MS experience cognitive impairments related to their disease. The effects of these impairments may be mild, often detectable only after comprehensive testing, and may include difficulty with any or all of the following:

    • Concentration

    • Attention

    • Memory

    • Poor judgment

Symptom categories of MS

Primary symptoms. A direct result of demyelination, the destruction of myelin (the fatty sheath that surrounds and insulates nerve fibers in the central nervous system) may result in the following:

  • Weakness

  • Numbness

  • Tremor

  • Loss of vision

  • Pain

  • Paralysis

  • Loss of balance

  • Bladder and bowel dysfunction

Secondary symptoms. Complications that arise as a result of the primary symptoms, for example:

  • Paralysis can lead to bedsores.

  • Bladder dysfunction may cause repeated urinary tract infections.

  • Inactivity can result in weakness, poor postural alignment and trunk control, muscle imbalances, decreased bone density, and/or shallow, inefficient breathing.

  • Becoming less mobile because of weakness and difficulty swallowing can lead to an increased risk of pneumonia.

Tertiary symptoms. The social, vocational, and psychological complications of the primary and secondary symptoms, for example:

  • A person who becomes unable to walk or drive may lose his or her livelihood.

  • Strain of dealing with a chronic neurological illness may disrupt personal relationships.

  • Depression is often seen among people with MS.

The symptoms of MS may resemble other medical conditions or problems. Always consult your doctor for a diagnosis.

Diagnostics and Testing

Multiple sclerosis is often difficult to diagnose. This is because there is no single test or finding on the examination that makes the diagnosis, and because the disorder varies from person to person. In most cases there is a history of neurological symptoms that come and go over years. The neurological examination may show changes that suggest problems with the spinal cord or brain. The MRI may show areas of abnormality that suggest MS, though the MRI in itself does not ?make the diagnosis?. Spinal fluid testing may show that the immune system is active in and around the brain and spinal cord, supporting the diagnosis. Evoked potentials may assist in diagnosis. All of these need to be put together by the physician to determine if MS is the actual diagnosis. Even when all the tests are done, some people cannot be diagnosed for years after the beginning of symptoms. An international panel of MS experts recently revised the ways that MS is diagnosed, providing a framework for clinicians to use in making the diagnosis. These new diagnostic criteria (The McDonald criteria) allow the diagnosis of MS if MRI scanning shows new lesions forming over time, making even earlier diagnosis possible. Even with these advances, there are some people where the diagnosis may be uncertain for years, due to the complexity and variation of MS.

In the pediatric age group, diagnosis is even more complex than for adults. This is because there are a large number of disorders that occur in childhood that may mimic MS. For example, acute disseminated encephalomyelitis (ADEM) is more common in childhood and may be confused with MS. Treatment for this disorder is different from MS in that ADEM is usually a one time illness, and does not require treatment after the initial acute episode. There are a variety of rare diseases, some genetic, some infectious, some due to other illnesses, that need to be distinguished from MS. Expert evaluation of the clinical history and physician examination, MRI appearance, cerebrospinal fluid, and other diagnostic testing is key to discriminating these other disorders from MS.

Factors which seem to predict a second attack of MS in children include optic neuritis, age greater than 10 years, or an MRI suggestive of MS with multiple well-defined periventricular or subcortical lesions.