Hindawi Publishing Corporation International Scholarly Research Notices Volume 2014, Article ID 307064, 7 pages http://dx.doi.org/10.1155/2014/307064 Review Article Disease Modifying Therapy in Multiple Sclerosis U. E. Williams, S. K. Oparah, and E. E. Philip-Ephraim Internal Medicine Department, University of Calabar, Calabar 540242, Cross River State, Nigeria Correspondence should be addressed to U. E. Williams; [email protected] Received 12 March 2014; Revised 7 May 2014; Accepted 7 May 2014; Published 7 July 2014 Academic Editor: Cristoforo Comi Copyright © 2014 U. E. Williams et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Multiple sclerosis is an autoimmune disease of the central nervous system characterized by inflammatory demyelination and axonal degeneration. It is the commonest cause of permanent disability in young adults. Environmental and genetic factors have been suggested in its etiology. Currently available disease modifying drugs are only effective in controlling inflammation but not prevention of neurodegeneration or accumulation of disability. Search for an effective neuroprotective therapy is at the forefront of multiple sclerosis research. 1. Introduction MS because there is no dissemination in time and space. The radiologically isolated syndrome (RIS) occurs when there Multiple sclerosis (MS) is an autoimmune disease of the cen- are MRI abnormalities suggestive of demyelination in the tral nervous system characterised by inflammation, demyeli- absence of clinical correlates [5]. Other types of MS based nation, and axonal degeneration. Lesions are dispersed in on the pattern of relapse, remission, and accumulation of space and time. It is the commonest neurological disease in disability include relapsing remitting (RRMS), secondary youngadultswithresultantpermanentdisability[1, 2]. There progressive (SPMS), primary progressive (PPMS), and pro- is geographic variation in the incidence and prevalence of gressive relapsing (PRMS). The likelihood of progressing MS.IntheUnitedKingdom(UK)annualprevalenceand from CIS to MS is directly related to the presence of CSF incidence rates are 7/100,000 and 120/100,000 respectively, oligoclonal bands (OCB), motor symptoms, and finding of with an average UK general practice (GP) caring for 2-3 high numbers of MRI white matter lesions. Positive MRI patients in their care. It is common among people of 18– white matter lesion at CIS suggest 50% probability of a second 50 years of age [2]. The male to female ratio is about 1 : 3. relapse within 2 years and 80% within 2 decades, but only 20% The higher female preponderance is thought to be due to the of patient with normal MRI will relapse in 20 years [2]. effects of hormonal differences that predisposes to a greater The presence of more than one clinically evident attack environmental susceptibility [3]. of demyelination separated by a period of partial or complete resolution and then stability prior to a second attack defines 2. Types of MS RRMS. A retrospective diagnosis of benign MS is made when there is lack of significant disability after about 20 The classic MS is characterised by periods of relapse and years of clinically evident demyelination [6, 7]. In SPMS remission. A relapse is any attack of demyelination seen symptoms gradually worsen without remission. PPMS are clinically as a new or sudden worsening of symptoms lasting marked by a progressively aggressive steady course with longer than 24 hours. Two relapses are usually separated little or no recovery from the onset of symptoms. In PRMS, by 30 days and may resolve completely or partially. The the symptoms steadily get worse from the onset, but with first single distinct episode of demyelination in the optic distinct relapse with or without recovery. About 80% of nerves, cerebellum, cerebrum, brainstem, and spinal cord is RRMS eventually evolve into SPMS, while about 20% of MS described as a clinical isolated syndrome (CIS) [4]. It is not is PPMS. 2 International Scholarly Research Notices 3. Aetiology and Pathogenesis of MS neuropathological studies [22]. The resultant inflammation, demyelination, and associated axonal degeneration are The aetiology of MS is unclear but epidemiological studies responsible for the clinical features of MS. do suggest an environmental and genetic basis, with the MS presents a complex picture of the interaction between lag in environmental exposure before clinical manifestation inflammation and neurodegeneration. Further documented suggestinga“prodromalphase”[8]. A poorly understood evidence for inflammation includes the production of reac- genetic association has been established between MS and tive oxygen species and cytokines and compliment activation, human lymphocyte antigen (HLA), particularly HLA-DR2 which is believed to initiate myelin damage and secondary and HLA-DRB1 [9]. Other genes implicated in MS include axonal loss [23]. The sequence of events between inflam- interleukin (IL)-7, IL-2, and tumour necrosis factor (TNF) mation and neurodegeneration is still hypothetical; some receptor super-family member 1A and interferon regulator scholars have proposed that neuronal and axonal damage factor-8 gene [10]. The genetic basis of the disease is further precedes demyelination (inside-out theory), while others supported by the fact that certain ethnic groups have a higher think demyelination occurs before axonal damage (outside- chance of having MS such as Native Americans compared in theory) [24]. with a lower incidence among African Americans [11]. An individual with a genetic susceptibility develops MS when exposed to environmental factors with strong associ- 4. Clinical Features of MS ation for developing MS such as Epstein-Barr virus (EBV), smoking, increasing latitude, and vitamin D deficiency. EBV The spatial distribution of MS plaques accounts for its varied hasbeendocumentedin90%ofpatientswithMS[12]. clinical features. Optic neuritis one of the commonest pre- Smokers have a higher risk of developing MS compared to sentationsofMSmanifestsaslossofcolourvision,decreased nonsmokers, and this risk is dose dependent [13]. Even in visual acuity, and gritty sensation in eye. Other findings in thesameregion,MSincidenceandprevalenceincreaseswith the eye include internuclear ophthalmoplegia, afferent pupil- latitude and is the strongest risk factor after ethnicity14 [ ]. The lary defect, saccadic ocular pursuit, and acquired pendular relationship between latitude and MS has been thought to be nystagmus [25].Furthercranialnervedamageisseenasloss due to the decreasing sunlight and Vitamin D with increasing of facial sensation, vertigo, and trigeminal neuralgia. Cortical latitudes, thus establishing an inverse relationship between plaques can result in cognitive impairment affecting memory MS susceptibility and sunlight [15]. The migrant country of and attention, but frank dementia is rare. Sensory involve- origin and the age of migration are also important in MS risk. ment is commonly seen as numbness, tingling, paraesthesia, Migrants after the age of 20 years retain the risk of their home tightness, coldness, radicular pain, and itchy sensation. country, while those who migrate earlier adopt the risk of Spinal plaques result in bladder, bowel, and sexual dys- their new country [16]. function, as well as Lhermitte’s sign, which describes as an The exact mechanism underlying the evolution from RIS electric shock-like sensation radiating down the spine on to CIS and eventually to MS is still unclear. Factors defined by flexion of the neck. Lesions involving the dorsal column result birth such as sex, HLA, and place of birth require the inciting in impaired proprioception. Patient may also have fatigue effect of risk factors in the environment to develop clinical unrelated to physical activity; Uhthoff ’s phenomenon where MS. MS is thought to be mediated by CD4 and CD8 T-cell and the patient’s symptoms worsen with activity that increases to a lesser extent humoral immune factors. Strong evidence in body temperature; and features of cerebellar dysfunction support of the humoral basis of MS is the intra-CFS synthesis such as gait imbalance, dysmetria, decomposition of complex of oligoclonal bands (OCB) [17]. Environmental factors are movements, intention tremors, scanning speech, and truncal believed to trigger T-cell autoimmune response against the ataxia. The finding of rubral tremor is an advance brain CNS in the periphery, the activated cells cross the blood brain stem feature in MS, with cardinal features being a complex barrier (BBB) after inflammatory cytokines have disrupted of ataxia, dysarthria, tremor of the extended upper limb, its integrity. The activated T-cells attack myelin-basic protein head titubation, and ophthalmoplegia. There is always a small and myelin oligodendrocytes glycoprotein with antigenic possibility of another family member having MS but not in an properties similar to that of the inciting environmental autosomal or mitochondrial pattern of inheritance. factor commonly an infectious agent, a phenomenon The diagnosis of MS has evolved over the years from referred to as molecular mimicry [18]. The disease is the Dawson criteria of 1916, to Schumacher criteria in 1965, activated by these autoreactive polyclonal lymphocytes and superseded by Poser criteria established in 1983 and finally macrophages but propagated by microglial