Multiple sclerosis in children and adolescents
Multiple sclerosis (MS) belongs to a group of autoimmune diseases that affect the central nervous system (CNS). The mechanism of all autoimmune diseases is that the immune system recognizes some proteins from which organs or tissues are built as “foreign,” and mistakenly attacks and destroys these proteins with its own lymphocytes.
MS is caused by an autoimmune reaction directed against the protein myelin, an essential component of the insulating sheath on nerve fibers of the CNS. Myelin is like a sleeve that covers the axons of nerve cells. It provides speed and accuracy for electrical signal transmissions of nerve impulses. In MS, the body perceives myelin as a foreign protein, and the immune system responds with an inflammatory reaction to destroy it. Damaging myelin leads to interruption in the transmission of nerve impulses, which manifests as neurological disorders of various body functions.
Since the autoimmune reaction can affect any part of the nervous system, the symptoms of MS are diverse and can appear as dysfunction of various organs and systems.
The onset of MS may be accompanied by the following signs and symptoms:
- crawling sensation on the skin;
- numbness with reduced sensitivity;
- muscle weakness up to paralysis;
- decrement in visual acuity up to blindness;
- changes of posture.
In 1868, a French neurologist Jean-Martin Charcot was the first to describe and diagnose MS as a distinct pathological issue. He described three specific symptoms of the disease, which include (1) abrupt speech, (2) tremor during voluntary movements and (3) involuntary, rhythmic, oscillatory movement of the eyes (nystagmus). Today, these symptoms are known as “Charcot's triad".
About a million people in the world have MS. In the United States, the number of MS patients has reached 350,000, and each year the number increases by 10,000 new patients. In Israel, the number of MS patients is approximately 4,000-5,000 people, and each year about 100 new patients are diagnosed. The disease is more common among women (with a ratio of 2:1 compared to men), and usually manifests at a young age, with the peak incidence occurring at the age of 25 years.
Scientific data strongly suggests that MS begins in childhood or adolescence. Many studies conducted in various countries indicate that between 2% and 5% of MS cases are diagnosed in children under the age of 16 years.
Some diseases have symptoms similar to symptoms of MS. For this reason, it is important to differentiate these diseases from MS in order to make an accurate diagnosis and provide appropriate treatment. The diseases that manifest symptoms similar to MS include optic neuritis, transverse myelitis and acute disseminated encephalomyelitis (ADEM). Sometimes the first MS symptoms are accompanied by non-specific symptoms, such as fever, decrease in cognitive ability, pathology of peripheral nervous system, too rapid advance of pathological processes, increased ESR (erythrocyte sedimentation rate), increased number of leukocytes, or increased amount of antibodies in the cerebrospinal fluid.
Factors that lead to development of the disease are still not clearly determined, but most doctors tend to believe that there are several factors influencing the onset of MS. Some of them are genetic; others are defined as impacts of the environment. For example, it is known that the risk to acquire MS increases if a family history has several confirmed cases of MS (about 15% of patients with multiple sclerosis have a relative with this disease). In addition to genetic and familial factors, there are also external influences.
Scientific research indicates that there is a relationship between multiple viral infections and the development of MS. Viral infections are believed to be one of the leading factors in the development of autoimmune diseases in general.
MS occurs more often in the Nordic countries, such as Northern Europe and North America. It is also known that migration at an early age from countries with cold climates into countries with warmer climates, reduces the risk of multiple sclerosis.
Clinical manifestations of MS
Bouts of the disease are periodic in nature. The neurological symptoms are observed in 85% of patients at the time of exacerbations only. These symptoms are:
- motor weakness, with possible paralysis of one or more limbs;
- reduced sensitivity, reflected in a sensation of tingling or numbness of certain body parts;
- lost of control over the sphincter;
- visual impairment, including blindness;
A few weeks later, the bout is over, sometimes with full or partial recovery. The prognosis of the disease depends upon the number of attacks, their manifestation and severity.
The next stage of the disease manifests in some patients with enhancement in the severity of the symptoms. Without drug treatment, 50% of all MS patients come to the second stage after about 10 years and develop a higher degree of neurological disability.
In 10% of patients, the primary stage of the disease is associated with more acute and severe neurological changes that lead to severe disability. Most of such cases are found in men older than 40 years. In this group of patients, disability occurs more rapidly and usually affects the lower extremities and sphincters. These symptoms indicate that the development of the pathological process takes place in the spinal cord.
In the expanded stage observed in 5% of patients, the bouts of illness are characterized by a moderate manifestation of neurological symptoms along with periodic acute attacks.
MS develops fairly slowly in children in most cases. According to the available data, children suffer more often from MS bouts than adults, but the symptoms also vanish faster.
The development of MS is usually estimated using a scale of the severity of movement disorders, known as the Kurtzke scale or EDSS (Expanded Disability Status Scale).
The first stages of MS in children are easier than in adults, but, unfortunately, disability in motor function and cognition occurs faster, and is accompanied by a large number of bouts. Because prophylactic treatment should be started as early as possible, treatment should be performed in combination with medications used to treat adult patients.
Because of how MS affects young people, it is important to strengthen preventive treatment among all children. For this reason, Sheba Hospital has created a unique system, founded in cooperation with the Center for Treatment of MS, that is the first of its kind in Israel. It is headed by Professor Anat Ahiron and Dr. Shay Menashko and Dr. Bruriya Ben-Zeev, of the Pediatric Neurology Department.
The Center for Treatment of MS is the joint work of highly skilled specialists, using the maximum of diagnostic capabilities available, and the scientific potential as well as practical achievements of the Children’s Hospital. We have built a strong system of monitoring and treatment of young patients suffering from MS in collaboration with Edmond and Lily Safra Children’s Hospital (especially with the additional support from the Institute of Metabolism, Institute for Brain Research, Departments of Rehabilitation of Children, Department of Neuropsychology, Department of Pediatric Neuroimmunology, and others).