Multiple sclerosis

Diane Madras

Introduction

As the life expectancy of the general population increases, so does the life expectancy of the population of older adults with disabilities. Life expectancy in those with multiple sclerosis (MS) is relatively normal, although some studies report lifespan may be reduced by 6–14 years (Stern, 2005). Therefore, aging with MS presents unique challenges for the physical therapist and the patient alike. Issues for people aging with MS pertain to minimizing disability and morbidity, and promoting functional independence and maximizing quality of life (Cruise & Lee, 2005).

Although there are data relating to all of the sequelae of MS, much of the early research on this disease involved younger subjects. Research is now beginning to examine the effects of aging on populations with MS. Many of the physiological changes of aging are similar to the effects of MS. The similarities include muscle atrophy, decreased cardiopulmonary reserve, impaired temperature regulation and depression (Stern, 2005).

This chapter will highlight the signs and symptoms associated with MS and identify issues that should be addressed in the rehabilitation of the aging patient who presents with MS.

Overview/epidemiology

MS, the most common disabling neurological disease in young adults (Goodman & Snyder, 2000), is most commonly diagnosed between 20 and 40 years of age. Although the cause remains unknown, several predisposing factors have been identified. Childhood forms were recently identified (Pugliatti et al., 2006; Govender et al., 2010; Absoud et al., 2011). Women are affected twice as often as men, and a family history of MS increases the risk by 10-fold. MS may be the result of a genetic predisposition or may be triggered by a virus or environmental factor. Environmental factors (Conradi et al., 2011) may affect the onset of symptoms since MS is five times more prevalent in the colder climates of North America and Europe than in tropical areas (Goodman & Snyder, 2000).

Natural history/classification

MS is classified as a progressive autoimmune disease characterized by chronic central nervous system (CNS) inflammation, demyelination and axonal damage. Demyelination leads to scarring (gliosis), which develops into plaques. The plaques (lesions) are distributed throughout the white matter of the CNS, leading to a wide array of brain and spinal cord syndromes (Goodman & Snyder, 2000; Stern, 2005). The plaques slow or block neuronal transmission resulting in motor and sensory disturbances and other symptoms such as fatigue, depression and pain. Clinically, patients can present with weakness, ataxia, visual disturbances, numbness, paresthesias, heat intolerance, fatigue, depression, pain, bowel and urinary dysfunction. Symptoms are variable, making the course of MS highly unpredictable. The progression of MS is related to several factors, including the neurological status 2 years post onset, and the frequency and severity of exacerbations and remissions. Disease-modifying drugs decrease the frequency and severity of exacerbations with variable success (Tremlett et al., 2010).

Approximately 85% of patients experience an abrupt onset of symptoms. Disease classification is based on the clinical course of signs and symptoms as the patient is followed over time. Approximately 80–85% of patients are initially diagnosed with relapsing–remitting MS, characterized by acute episodes of worsening symptoms (referred to as either relapses or exacerbations) with complete or incomplete recovery of function. Relapsing–remitting MS (the most common form) is characterized by symptoms that develop over a period of a few hours to a few days, followed by complete or incomplete recovery and a stable course known as ‘remission’ between relapses.

Almost 50% of patients with relapsing–remitting MS eventually develop secondary progressive MS (SP-MS), characterized by gradual neurological deterioration with or without superimposed acute relapses. Approximately 10% of patients over 40 years of age diagnosed with MS experience continued disease progression from the outset with only minor fluctuations in function and are classified as primary progressive (PP-MS).

Progressive-relapsing MS, a rare form of the disease, is characterized by gradual neurological deterioration from the onset of symptoms and subsequent superimposed relapses (Stern, 2005). A relatively new classification of MS has been established, known as clinically isolated syndrome (CIS), where an individual with findings on magnetic resonance imaging (MRI) suggestive of MS experiences a single episode followed by a benign disease course (Nielsen et al., 2007; Mastorodemos et al., 2010). Table 29.1 summarizes each of the major subtypes of MS.

Table 29.1

Classification of MS based on clinical course

Relapsing remitting	Fluctuating course; sudden onset of new symptoms or reappearance of previous symptoms followed by complete or incomplete recovery. Slow accumulation of disability
Secondary progressive	Absence of remission with more rapid progression of symptoms and accumulating disability; develops from relapsing–remitting course
Primary progressive	Slow progression of symptoms from onset of disease with no remission of symptoms, and steady accumulation of disability
Clinically isolated syndrome	MRI evidence and a single episode of MS exacerbation followed by very slow or little accumulation of disability

Diagnosis/medical management

Diagnosis

The prevalence of MS is increasing worldwide, as diagnostic criteria become more refined and MRI technology improves (Albertyn et al., 2010; Chen et al., 2010; Cheng et al., 2010). The diagnosis of MS is usually made based on a variety of information sources such as a thorough medical history, physical, neurological and laboratory examination and, potentially, imaging studies. Usually the patient presents to a medical professional reporting one or more symptoms occurring intermittently over time. Suspicion of MS increases when abnormalities noted on physical examination and MRI with gadolinium are disseminated in space and time. Although the diagnostic criteria are still under debate, the use of the Poser and revised McDonald criteria are improving the accuracy of diagnosing CIS and MS worldwide (Polman et al., 2011). MS lesions visible on MRI are thought to identify white matter lesions and demonstrate the breakdown in the blood–brain barrier occurring during acute MS activity (when a symptom is present for less than 6 weeks). The physiological process of normal aging (Schuster et al., 2011) can also produce hyper-intense foci in the subcortical region on MRI, therefore the older adult with MS presents a challenge for differentiating between new disease activity, normal aging and a stroke. Imaging of both the brain and spinal cord can assist in the differential diagnosis of MS or other neurological disease processes (Bot et al., 2012). Patients with MS are classified on the Expanded Disability Status Scale published by Kurtzke in 1983.

MS management

The availability of disease-modifying drugs has increased since 1993, with nine therapeutic agents currently available. Presently, there are two oral medications – Aubagio (teriflunomide) and Gilenya (fingolimod) – and four subcutaneous injectable medications – Betaseron (interferon beta-1b), Copaxone (glatiramer acetate), Extavia (interferon beta-1b) and Rebif (interferon beta-1a). One intramuscular injectable medication – Avonex (interferon beta-1a) – and two delivered by infusion – Novantrone (Mitoxantrone) and Tysabri (Natalizumab) – are also available (National Multiple Sclerosis Society, 2012).

Exacerbation management

Minimizing duration and severity of an exacerbation (or flare) is the goal of medical management of patients with MS during an exacerbation. The primary medications administered during acute episodes are Solu-Medrol (methylprednisolone), Decadron (dexamethasone), or ACTH (adrenocorticotropic hormone). Corticosteroids may become problematic in an older individual since potential side-effects include immunosuppression and increased osteoporosis from lack of activity (National Multiple Sclerosis Society, 2012).

Aging with and clinical features of MS

Many clinical manifestations are shared by aging and MS, such as ophthalmic changes, cognitive dysfunction, bowel and bladder dysfunction, sensory changes, balance dysfunction and sexual dysfunction, all of which can contribute to decreased quality of life.

The physiological changes that occur during the process of aging present additional challenges for MS patients, caregivers and practitioners. Although many traditional physical therapy approaches are effective in the management of the ailments associated with aging, elderly patients with MS require special consideration. One consideration in older adults is their susceptibility to adverse drug side effects because of decreased physiological reserve impacting liver and kidney function. Table 29.2 outlines the various manifestations associated with aging with MS and issues that require special consideration (Stern, 2005).

Table 29.2

Clinical manifestations and special considerations in the older adult with MS

Clinical Feature	Description	Impact of Aging	Treatment Considerations
Ophthalmological symptoms	Affects 80% of patients. Leads to decreased ADLs and employment. Most common: optic neuritis, internuclear ophthalmoplegia and nystagmus. Symptoms: blurred vision, scotoma, impaired color vision and contrast sensitivity, pain with eye movement	In older population: presbyopia, cataracts, macular degeneration and glaucoma compound visual disturbances. Leads to further isolation and decreased self-care	Environmental adaptations include outlining doorways and stairs. Reduce glare and use magnifiers. Diplopia: eye patching or glasses with prism lenses
Fatigue	One of the most debilitating symptoms, occurring in over two-thirds of patients. Includes decreased energy; malaise; motor weakness during sustained activity; and difficulty concentrating. Interferes with work, family and social life	Look for secondary causes, e.g. infection; cancer; anemia; hypothyroidism; rheumatological conditions; diseases of the cardiovascular, pulmonary, renal or hepatic systems. Other factors include depression, pain, deconditioning or exposure to heated environment	Medication side-effects also contribute: TCAs; benzodiazepines; anticonvulsants; beta blockers; interferons; anti-spasticity medications. Intervention includes energy conservation and aerobic exercise. Medication: caution with older adults, e.g. use of stimulants, i.e. amantadine, associated with risk of cardiac side-effects
Heat intolerance	Frequently associated with increase in severity of symptoms. Excessive heat is caused by weather, over exercising or fever	Elderly vulnerable to hyperthermia because of loss of homeostatic temperature regulation, decreased ANS function, decreased sweat gland function, loss of subcutaneous fat	Outside activity should be performed in early morning; use air-conditioning in home and car; wear light clothes or cooling vest; avoid saunas, hot tubs. Ideal pool temperature 85°F (29.4°C)
Depression	Most common mood disorder; caused by a neuroanatomical or neurochemical changes. Incidence three times greater than the general population	Often overlooked because of symptoms of fatigue, decreased activity level and decreased concentration. Depression rating scales have limited utility in the MS population	Use of antidepressants also helpful in pain management. There are depressive side-effects from other medications including anxiolytics; beta blockers; methyldopa; clonidine; reserpine; steroids. There is a 7.5 times greater risk of suicide: duration and severity of disease not factors but major depression, living alone and alcohol abuse are
Cognitive dysfunction	Mild cognitive dysfunction; 5–10% have severe condition. Deficits include decreased short-term memory, reasoning, verbal fluency, abstract reasoning and speed of information processing. Intellectual functions intact	In aging, slowing of frontal lobe processes leads to decreased learning rate. Aging MS patient at greater risk for cognitive impairment	Medications may also be a factor, for example anticholinergics, antispasmodics, opioids, benzodiazepines, TCAs. Use lists, calendars and journals to assist with memory deficits
Sensory disturbance	Most common initial symptom: affects>50% of patients. Includes paresthesia; numbness; loss of proprioception; neuropathic pain; acute pain because of inflammation; chronic pain from increased muscle tone or musculoskeletal changes	Seen with longer duration of disease, therefore common in older patients. Aging associated with musculoskeletal degeneration; may aggravate symptoms. With aging patient, rule out other etiology of pain, i.e. cervical spondylosis: look for neck and reticular pain; muscle atrophy; decreased deep tendon reflexes	MS patients often under-treated for pain. Pain treated with opioid analgesics, and NSAIDs, antiseizure medications, antidepressants and antispecificity agents. Intrathecal baclofen pump may be beneficial for intractable pain and spasming. Assess posture and wheelchair seating. Use appropriate assistive devices to decrease strain and overuse of muscles if inefficient gait is observed. Assess skin integrity with sensory loss
Cerebellar symptoms	Seen in one-third of patients. Disabling tremors affect any muscle group. Increases fatigue because of increased energy consumption	Aging also affects balance in general population: cerebellar symptoms may further increase fall risk	No effective medications. Review fall precautions. Home assessment may be helpful to increase safety
Motor loss and spasticity	Present in>60% of patients; results from corticospinal involvement. Lower extremities involved more than upper extremities. Energy requirement increases for activity with spasticity	Weakness associated with aging because of lower motor neuron denervation and atrophy. Rule out secondary causes in aging patient with spasticity: infections, skin breakdown, spinal stenosis with myelopathy	Oral medications for spasticity must be monitored closely. Baclofen: lower initial dose and slower titration decreases risk of sedation and confusion. Benzodiazepines: increased half-life and higher association with agitation and disequilibrium
Bladder dysfunction	Affects 96% with>10 years history; detrusor hyperreflexia is most common. Urinary tract dysfunction can lead to bladder or renal stones and frequent UTI	Anatomical and physiological changes because of aging can cause urinary frequency, hesitancy, retention and nocturia. Incontinence can be caused by delirium, atrophic vaginitis, enlarged prostate, constipation	Elderly sensitive to urological side-effects of medications used to treat MS. Take into consideration level of disability; manual dexterity; other medical problems; provide social support for decisions regarding intermittent catheterization versus indwelling catheter
Bowel disturbance	Constipation most common because of pelvic floor spasticity, decreased gastrocolic reflex, decreased hydration, medication, immobility, weak abdominal muscles	Slowed motility of gastrointestinal tract seen in older adult	Medications (anti-cholinergics, TCAs, antihypertensives, iron, calcium, opioids) may exacerbate constipation in elderly; regular bowel program may be necessary; rehabilitation to increase mobility may also be beneficial