Introduction

Multiple sclerosis (MS) is one of the most dreaded diagnoses in neurology. Patients visualise a fit and healthy person, such as the Olympic athlete Betty Cuthbert, reduced to a wheelchair existence. Patients told the diagnosis of MS are often reduced to tears in much the same way as the diagnosis of cancer causes patients to jettison hope. This should no longer be the case in the light of recent advances in the treatment of MS. In the past, the neurologist’s waiting room was crowded with the wheelchairs of patients with MS but, thankfully, this has now become the exception rather than the rule.

Even the understanding of the basic pathophysiology of MS has changed enormously over the last decade. It used to be thought that MS was purely a white T-cell autoimmune demyelinating central nervous system (CNS) disease. More recently, the immunological role of B-lymphocytes in the evolution of MS has been appreciated, as has the major contribution of the associated axonal degeneration that causes shrinkage of the brain volume. To better understand the concept of demyelination contrasted with axonal degeneration, the reader is referred to Chapter 11 on peripheral neuropathy in which the issues are discussed in depth. The basic concepts remain the same although the location is the central rather than the peripheral nervous system.

One reason MS is feared is that it is an unpredictable disease with exacerbations and remissions. It is a disease in which lesions occur within the CNS that are ‘separated in time and place’. The diagnostic criteria for MS have also been modified with the international acceptance of the ‘McDonald criteria’ (see Table 10.1).

These criteria acknowledge the role of magnetic resonance imaging (MRI) in the diagnosis of MS. The criteria, formulated by a panel of experts chaired by McDonald, recognised that MS may be identified by clinical symptoms and signs, MRI detected lesions (that may occur without associated clinical features) and the presence of oligoclonal bands in the cerebral spinal fluid (CSF) that herald CSF immunological insult.¹

The easier access to MRI has produced a practical recognition that for every clinically identified ‘attack’ of MS, there may be as many as six to ten sub-clinical ‘attacks’ that would remain silent were it not for the MRI trademark of the MS plaque.

While the treatment of MS remains largely the precinct of the consultant neurologist, there should exist an effective partnership between the neurologist and the general practitioner to maximise patient wellbeing. The role of the general practitioner within this partnership should not be underrated, and is mandatory for an optimal outcome. This chapter maps out the clinical features of MS so that the diagnosis is appropriately made, without which this partnership cannot operate to the patient’s advantage.

There is a variety of types of MS, and it is accepted that not all types respond equally to accepted MS treatment. Use of disease modifying agents, such as the interferons or glatiramer acetate, requires a diagnosis of MS confirmed by MRI² (the date of that MRI being part of the prescription approval process), but these agents are not available to patients with advanced disability (unable to walk more than 100 metres without assistance). This is equivalent to the disability rating of 6.0 on the Expanded Disability Status Scale (EDSS)³ (see Table 10.2).

TABLE 10.2 Expanded disability status scale

These agents are likewise denied to patients with MS who do not have relapsing remitting MS (RRMS). Patients with progressive disease are at a distinct disadvantage and, in many instances, symptomatic relief as provided by the general practitioner is the only therapeutic option available on the Pharmaceutical Benefits Scheme (PBS).

Diagnosing MS

A repeated mantra in this book is that ‘without heightened index of suspicion the diagnosis will often be missed’. This is equally true and important when diagnosing MS.

MS occurs more commonly in females than males (ratio 2 : 1), usually between the ages of 20 and 40 years, although childhood and geriatric onset are now becoming more widely diagnosed because of MRI. The diagnosis of MS is becoming more common, but it is suspected that this reflects better diagnostic tools and heightened index of suspicion rather than an increased prevalence.

If the place of birth is further from the equator, migration after the age of 15 years means one brings the prevalence of MS of the place of origin to the destination rather than assuming the prevalence appropriate to the destination. Within the Australian context, the incidence of MS is sixfold greater in Tasmania than in northern Queensland. Some argue that this relates to an increased exposure to sunlight and vitamin D, which occurs closer to the equator, but the absolute answer remains unclear. If one parent has MS there is a 1–2% chance of the child having MS and, if a monozygotic twin has MS, then the chance of the sibling twin developing MS is of the order of 35%. There is a suspicion of an association between MS and previous infection with the Epstein-Barr (EB) virus. It follows that there is a variety of red flags that should alert the general practitioner to the possibility of MS.⁴

Because the presentation of MS can be so varied, it is most important, especially when assessing young women, not to dismiss symptoms that are difficult to understand. If it is possible for the symptoms to emanate from the CNS, then the diagnosis of MS should be entertained. As a rule of thumb, the diagnosis of MS is beyond the scope of the average general practitioner. It requires lumbar puncture, looking for oligoclonal bands; evoked potential studies (including visual, somatosensory and possibly brainstem) looking for lesions that are separated in place (located within the CNS); as well as the MRI. Despite general practitioners now having greater access to MRI, in reality, to diagnose MS most general practitioners will refer the patient to a consultant before ordering an MRI. Another reason for early referral is that there is good evidence to suggest that the earlier treatment is instigated, the better is the outcome.² A number of companies are now offering special compassionate access to disease modifying drugs for patients with Clinically Isolated Syndrome (CIS)—for patients having experienced a single attack without meeting the criteria for a definitive diagnosis of MS—to ensure the earliest possible availability of treatment. This further recognises the merit of early intervention on long-term prognosis.

As stated in other chapters, it is far more intellectually rewarding for the general practitioner to refer the patient to the consultant with a confirmed and correct provisional diagnosis, so the family doctor needs to be aware of the symptoms of MS to take an appropriate history (see Table 10.3).

TABLE 10.3 Symptoms of MS