MEDIA BACKGROUNDER. Multiple Sclerosis: A serious and unpredictable neurological disease

Transcription

1 MEDIA BACKGROUNDER Multiple Sclerosis: A serious and unpredictable neurological disease Multiple sclerosis (MS) is a complex chronic inflammatory disease of the central nervous system (CNS) that still represents a medical challenge. MS is the most common disabling neurological disease in young adults after accidents. MS is two to three times more common in women; and men have a tendency for later disease onset with a worse prognosis. 1 Even though it usually starts between the ages of 20 and 50, MS can actually occur at any age. 1. A multifaceted and unpredictable disease MS is an autoimmune disease that affects the central nervous system. It is characterized by multifocal areas of scar tissue (sclerosis) that lead to irreversible damage to the myelin sheaths that protect nerve cell axons. This process of demyelination actually takes away the protection of nerve fibers, which in turn reduces or even blocks electrical signals from the brain to the eyes, muscles, and other parts of the body. The accumulation of brain lesions over time is what leads to irreversible physical and neurological impairment. These lesions occur during relapses. MS is unpredictable because the time at which patients may experience relapses and remissions cannot be estimated. This means that patients with MS have to live one day at a time. 2. A broad and uneven distribution MS affects more than 2,000,000 million people worldwide. Epidemiological studies 2 reveal that the distribution of the patient population is uneven. The highest prevalence rates are in the northern hemisphere, including Europe and North America (e.g., 176 per 100,000 in Hungary; 149 per 100,000 in Germany; 135 per 100,000 in North America), whereas Asia, Africa and South America have much lower prevalence levels (from <30/100,000). Page 1 of 5

2 Prevalence of multiple sclerosis in the world in The age group with the highest numbers of patients has been estimated to be within the year old group for both sexes and for all countries, making MS the most common cause of neurological disability in young adults. Prevalence rates are significantly higher for women around the world, with a female:male ratio of 2: Uncertain causes, but clear symptoms The origin or causes of MS remain uncertain, although current evidence suggests that it is an autoimmune disorder of the CNS resulting from an environmental stimulus in genetically susceptible individuals. MS has variable clinical aspects: Inflammation, demyelination and axon degeneration are the major pathological mechanisms that cause the clinical manifestations. In its later stages, the disease is dominated by microglial activation and chronic neurodegeneration. The most widely accepted theory to date is that MS is an inflammatory autoimmune disorder mediated by autoreactive lymphocytes. Symptoms vary from patient to patient and over time according to the location of lesions in the brain and spinal cord. Symptoms may include changes in sensation; muscle weakness; difficulty in moving; problems in speech or swallowing; visual problems; fatigue; acute or chronic pain; bladder and bowel control difficulties; urinary dysfunction; sleep disturbance. Cognitive impairment of varying degrees and emotional symptoms, such as depression are also common. 4. Typical disease patterns There are four internationally recognized subtypes of MS, characterized by their pattern of progression: 4 Page 2 of 5

3 Clinically isolated syndrome (CIS): In some MS patients, the onset of disease presents as a single cause of acute clinical event. This event involves either focal or multifocal brain regions with sensorial, visual, cerebellar and motor symptoms. In CIS, a patient has an attack suggestive of demyelination, but does not fulfil the criteria for multiple sclerosis. Approximately 70% of people experiencing CIS will later have subsequent relapses, fulfilling the clinical criteria for relapsing-remitting forms of MS (RRMS). Relapsing-remitting (RRMS) pattern: Exacerbations alternate with remissions, when partial or full recovery occurs or symptoms are stable. Remissions may last months or years. Exacerbations can occur spontaneously or can be triggered by an infection, such as influenza. Patients with worsening RRMS and secondary progressive MS (SPMS), despite treatment with disease modifying treatments (DMTs), are said to have breakthrough disease. 90% of MS patients are RRMS patients at the time of diagnosis. Secondary progressive (SPMS) pattern: This pattern begins with relapses alternating with partial remissions, followed by gradual progression of the disease without relapses. It occurs in 65% of patients who have had RRMS. Primary progressive (PPMS) pattern: The disease progresses gradually with no remissions, although there may be temporary plateaus during which the disease does not progress. Unlike in the RRMS pattern, there are no clear exacerbations. It accounts for less than 20% of MS cases. Progressive relapsing pattern: The disease progresses gradually, but progression is interrupted by sudden, clear relapses. This pattern is rare. It is widely accepted that about 90% of cases begin as RRMS. The estimated time of conversion to secondary progression differs depending on sources, with a median time of conversion of around 19 to 20 years. 11 The prognosis of MS patients is difficult to predict; it depends on the subtype of the disease, the individual patient's disease characteristics, the initial symptoms and the degree of disability the person experiences as time advances. 12 Nonetheless, age at onset of MS is the strongest predictor of the conversion to secondary progressive disease; the older the patient at onset, the shorter time to onset progression Current patient management strategies Current therapies fall into different groups: The DMTs regulate the immune system, with the objective to prevent inflammation which causes relapses and thus, slow down the disease evolution. They can reduce the frequency and severity of MS relapses, which in turn reduces the risk of acquiring irreversible Expanded Disability Status Scale (EDSS) handicaps. Exacerbation treatments enable a decrease in severity and duration of MS relapses by suppressing inflammation. Symptomatic treatments help patients to cope with MS related manifestations: Fatigue, spasticity, pain and depression. Non-drug therapies, such as physiotherapy and rehabilitation, can also provide relief for certain symptoms. The management of patients with MS requires intervention from several medical specialties, including neurologists, general practitioners, ophthalmologists, physical therapists, psychologists and social workers. Page 3 of 5

4 Once a patient is suspected of having MS, he or she is referred to a neurologist or a rehabilitation specialist for a more complete disease assessment. According to certain professionals, this stage is one of the most crucial points in the patient care pathway as it determines the progression and activity of the disease and therefore the treatment options. The internationally accepted and practiced McDonald Diagnostic Criteria 5 is used to provide an accurate method for diagnosis based on symptoms, disability and disease pattern. Magnetic resonance imaging (MRI) is a common and important tool used to help establish a diagnosis of MS and monitor the course of the disease and effects of treatment. Providing a highly sensitive, non-invasive way to image the brain, spinal cord or other areas of the body, MRI has made it possible to visualize and understand a great deal about the underlying pathology of MS. 6. Still no cure, yet an important disease burden Despite major advances in the last 15 years, MS cannot be cured. Current treatment strategies slow down the progression of the disease, treat relapses, and manage symptoms to best preserve patients quality of life. Beyond the physical pain, MS has a major social and economic impact. The loss of independence and mobility, accompanied by cognitive dysfunction and persistent fatigue forces half of MS to stop their professional activity 10 years after the onset of their disease. 6 This mainly affects people aged who are in the midst of their most productive years. On average, 25% will not be able to walk within 25 years and many will also suffer from depression. All of these consequences can have a major impact on lifestyle and relationships with partners and family members. Older patients, aged 40 and above at onset, will tend to progress more rapidly to secondary progressive disease. 7 ~83-68% 3 ~76-30% 3 ~40-10% 3 ~9-1% 3 EDSS score and rate of employment10 The economic burden of MS is significant. The annual costs of MS patients vary significantly across countries. The aggregate amounts that are being spent in 28 European countries, taking into consideration earnings loss, treatment and informal care ranges from eight to 12.5 billion Euros. 8 Lifetime costs for MS patients in the US have been estimated to be around 2.2 million USD. 9 Page 4 of 5

5 References: 1. August 23rd M. Pugliattia,b, G. Rosatia, H. Cartonc, T. Riiseb, J. Drulovicd, L. Ve cseie and I. Milanovf, The epidemiology of multiple sclerosis in Europe. European Journal of Neurology 2006, 13: August 12th Date of Access October 8th Polman CH, Reingold SC, Edan G, Filippi M, Hartung HP, Kappos L, Lublin FD, Metz LM, McFarland HF. Diagnostic criteria for multiple sclerosis: 2010 revisions to the McDonald Criteria. Ann Neurol : Langgartner M, Langgartner I, Drlicek M. Clinical Review, The patient s journey: Multiple Sclerosis BMJ 2005:330: Confavreux C, Vukusic S. Age at disability milestones in multiple sclerosis. Brain 2006; 129(Pt 3): Sobocki P, Pugliatti M, Lauer K, Kobelt G. Estimation of the cost of MS in Europe: extrapolations from a multinational cost study. Mult Scler 2007;13(8): Whetten-Goldstein K et al., A comprehensive assessment of the cost of multiple sclerosis in the United States Mult Scler October : "Rating neurologic impairment in multiple sclerosis: an expanded disability status scale (EDSS)". Neurology 33 (11): PMID Convafreux C : Early clinical predictors and progression of irreversible disability in multiple sclerosis: an amnesic process Brain Apr;126(Pt 4): Natural History of Multiple Sclerosis J Neurol Neurosurg Psychiatry 2001;71 (suppl II):ii16 ii19 Page 5 of 5