CHAPTER 134
Multiple Sclerosis
Definition
Multiple sclerosis (MS) can be defined as an inflammatory disorder that results in damage, primarily to myelin sheaths and oligodendrocytes and less so to axons and nerve cells, in the central nervous system [1,2].
The prevalence of MS has been estimated at 300,000 to 400,000 in the United States and 2 million worldwide [3]. The disease usually becomes clinically apparent between the ages of 20 and 40 years, with a peak incidence at 24 to 30 years and onset as late as the seventh decade [3]. The disease appears twice as likely to develop in women as in men, and whites are more frequently diagnosed than are other races [3]. Although African Americans may experience greater MS-related disability than white individuals do, the disease progresses similarly for both races [3,4].
There are four common clinical courses in MS:
• Secondary progressive MS: Patients initially experience a relapsing-remitting course followed by progression of the disease with or without additional episodes of exacerbation and improvement. Most patients eventually transition to this disease course.
• Primary progressive MS: Patients experience a relentless progression of symptoms from the onset [5,6].
• Progressive relapsing MS: Patients experience a baseline progressive course with episodes of acute relapses followed by a return to the baseline progressive course.
MS can be diagnosed if there is evidence of two attacks disseminated in time and space with clinical, laboratory, or imaging evidence of at least two lesions in the brain or spinal cord [1–3,7]. Evidence may be obtained from clinical findings, magnetic resonance imaging, cerebrospinal fluid analysis, or visual evoked potentials [6,7]. Other diseases that could explain the symptoms must be excluded (see differential diagnosis) [8,9]. The most recent guidelines and revisions do not recommend the use of “clinically definite MS” or “probable MS”; the outcome of a diagnostic evaluation is MS, “possible MS,” or “not MS” (Table 134.1) [2,6,7].
Table 134.1
The 2010 McDonald Criteria for Diagnosis of Multiple Sclerosis
| Clinical Presentation | Additional Data Needed for MS Diagnosis |
| ≥ 2 attacks*; objective clinical evidence of ≥ 2 lesions or objective clinical evidence of 1 lesion with reasonable historical evidence of a prior attack† | None‡ |
| ≥ 2 attacks*; objective clinical evidence of 1 lesion | Dissemination in space, demonstrated by: ≥ 1 T2 lesion in at least 2 of 4 MS-typical regions of the CNS (periventricular, juxtacortical, infratentorial, or spinal cord)§; or Await a further clinical attack* implicating a different CNS site |
| 1 attack*; objective clinical evidence of ≥ 2 lesions | Dissemination in time, demonstrated by: Simultaneous presence of asymptomatic gadolinium-enhancing and nonenhancing lesions at any time; or A new T2 and/or gadolinium-enhancing lesion(s) on follow-up MRI, irrespective of its timing with reference to a baseline scan; or Await a second clinical attack* |
| 1 attack*; objective clinical evidence of 1 lesion (clinically isolated syndrome) | Dissemination in space and time, demonstrated by: For DIS: ≥ 1 T2 lesion in at least 2 of 4 MS-typical regions of the CNS (periventricular, juxtacortical, infratentorial, or spinal cord)§; or Await a second clinical attack* implicating a different CNS site; and For DIT: Simultaneous presence of asymptomatic gadolinium-enhancing and nonenhancing lesions at any time; or A new T2 and/or gadolinium-enhancing lesion(s) on follow-up MRI, irrespective of its timing with reference to a baseline scan; or Await a second clinical attack* |
| Insidious neurological progression suggestive of MS (PPMS) | 1 year of disease progression (retrospectively or prospectively determined) plus 2 of 3 of the following criteria§: 1. Evidence for DIS in the brain based on ≥ 1 T2 lesions in the MS-characteristic (periventricular, juxtacortical, or infratentorial) regions 2.Evidence for DIS in the spinal cord based on ≥ 2 T2 lesions in the cord 3. Positive CSF (isoelectric focusing evidence of oligoclonal bands and/or elevated IgG index) |
From Polman CH, Reingold SC, Banwell B, et al. Diagnostic criteria for multiple sclerosis: 2010 revisions to the McDonald criteria. Ann Neurol 2011;69:292-302.
If the criteria are fulfilled and there is no better explanation for the clinical presentation, the diagnosis is “MS”; if suspicious, but the criteria are not completely met, the diagnosis is “possible MS”; if another diagnosis arises during the evaluation that better explains the clinical presentation, then the diagnosis is “not MS.”
MS, multiple sclerosis; CNS, central nervous system; MRI, magnetic resonance imaging; DIS, dissemination in space; DIT, dissemination in time; PPMS, primary progressive multiple sclerosis; CSF, cerebrospinal fluid; IgG, immunoglobulin G.
* An attack (relapse; exacerbation) is defined as patient-reported or objectively observed events typical of an acute inflammatory demyelinating event in the CNS, current or historical, with duration of at least 24 hours, in the absence of fever or infection. It should be documented by contemporaneous neurological examination, but some historical events with symptoms and evolution characteristic for MS, but for which no objective neurological findings are documented, can provide reasonable evidence of a prior demyelinating event. Reports of paroxysmal symptoms (historical or current) should, however, consist of multiple episodes occurring over not less than 24 hours. Before a definite diagnosis of MS can be made, at least 1 attack must be corroborated by findings on neurological examination, visual evoked potential response in patients reporting prior visual disturbance, or MRI consistent with demyelination in the area of the CNS implicated in the historical report of neurological symptoms.
† Clinical diagnosis based on objective clinical findings for 2 attacks is most secure. Reasonable historical evidence for 1 past attack, in the absence of documented objective neurological findings, can include historical events with symptoms and evolution characteristics for a prior inflammatory demyelinating event; at least 1 attack, however, must be supported by objective findings.
‡ No additional tests are required. However, it is desirable that any diagnosis of MS be made with access to imaging based on these criteria. If imaging or other tests (for instance, CSF) are undertaken and are negative, extreme caution needs to be taken before making a diagnosis of MS, and alternative diagnoses must be considered. There must be no better explanation for the clinical presentation, and objective evidence must be present to support a diagnosis of MS.
§ Gadolinium-enhancing lesions are not required; symptomatic lesions are excluded from consideration in subjects with brainstem or spinal cord syndromes.
Symptoms
Symptoms of MS may involve multiple systems [10,11] (Table 134.2). Motor symptoms typically include weakness and spasticity [11]. Up to 85% of patients with MS may experience spasticity, and as many as a third may be affected by spasticity that is severe enough to diminish their quality of life [12]. Patients with MS may report paroxysmal spasms or nocturnal spasms.
Table 134.2
Common Symptoms in Multiple Sclerosis
| Bladder symptoms | Urgency, frequency, hesitancy, retention, incontinence |
| Bowel symptoms | Constipation, urgency, incontinence |
| Cerebellar symptoms | Incoordination, imbalance, tremor |
| Cognition | Concentration, memory, executive dysfunction |
| Fatigue | Lassitude, reduced endurance |
| Mood disorders | Depression, anxiety, emotional lability |
| Motor | Weakness, spasticity |
| Sensory symptoms | Loss of sensation, positive sensations |
| Sexual dysfunction | Decreased libido, erectile dysfunction |
| Vision | Visual loss and double vision |
From Goldman MD, Cohen JA, Fox RJ, Bethoux FA. Multiple sclerosis: treating symptoms, and other general medical issues. Cleve Clin J Med 2006;73:178.
MS may be the cause of decreased or even absent sensation in various body parts, including sensory levels that most often affect the trunk. Paresthesia (uncomfortable abnormal sensation that may be described by the patient as pain, pins and needles, or tingling) can occur in up to 50% of patients with MS and most commonly is neuropathic. Lhermitte sign is an electric shock–like sensation that radiates down the spine to the legs when the neck is flexed [10]. It may occur in up to 40% of patients with MS [7]. Multiple pain syndromes may occur in patients with MS [11,13] (Table 134.3). Visual symptoms may include optic neuritis that results from inflammation of the optic nerves and typically is manifested as retro-orbital pain or painful eye movements [14]. Visual deficits can range from mild distortions to complete visual loss [14]. Scotoma may be present as an area in the visual field with absent or impaired vision and dyschromatopsia as imperfect color vision [14]. Ocular motor deficits usually include internuclear ophthalmoplegia and nystagmus and are manifested as diplopia, blurry vision, and reading fatigue [14].
Cerebellar symptoms may include tremor, which can range from mildly annoying to disabling, be gross or fine, and occur at rest or with purposeful actions. Various parts of the body may be involved, including the head, the upper or lower limbs, and the trunk.
Constipation and bowel incontinence may occur in up to 73% of patients with MS [15]. More than 70% of patients with MS may suffer from bladder dysfunction [15]. MS lesions in the spinal cord can result in a small spastic bladder due to detrusor overactivity. This usually is manifested as urinary urgency, frequency, voiding of small amounts of urine, and eventually incontinence [15]. Bladder underactivity can result in retention and overflow incontinence. Bladder dysfunction is often associated with urinary tract infections that can worsen MS symptoms. Sexual dysfunction commonly includes erectile and ejaculatory dysfunction in men; vaginal dryness in women; and increased time to arousal, decreased genital sensation, and decreased libido in men and women [15]. Factors contributing to sexual dysfunction include disease progression, antidepressants, fatigue, and depression [15].
Involvement of cranial nerves VII, IX, X, and XII may result in dysphagia or swallowing difficulties. These are manifested as coughing, frequent throat clearing, complaints of food “sticking” in the throat, weight loss, weak voice, choking, or even aspiration pneumonia [16].
Fatigue has been reported to occur in more than 90% of MS patients and is regarded as the most disabling symptom in as many as 60% of these patients [15,17]. MS-related fatigue has been described as an overwhelming feeling of tiredness, lack of energy, or exhaustion exceeding the expected [15,17].
As many as 50% of patients with MS may have cognitive deficits that are manifested as problems with memory, planning, concentration, judgment, problem solving, and processing speed [18–21]. MS patients frequently report heat intolerance with an exacerbation of symptoms in warm or humid environments [22].
Physical Examination
Inflammation of the optic nerve may result in optic or retrobulbar neuritis manifesting as acute vision loss. Even after treatment, vision deficits may persist in the form of poor vision, especially in dim light, or blind spots in the visual field known as scotomas. Demyelination in the medial longitudinal fasciculus may result in varying degrees of horizontal nystagmus; involvement of the third cranial nerve may be manifested as a persistently enlarged pupil. Double vision may be attributable to weakened strength and coordination in the eye muscles. Cataracts may develop at an earlier age in the MS population because of the use of steroids. Visual problems may worsen with stress, increased temperature, and infection [14].
Speech dysfunction may include dysarthria with diminished fluency, slurring, decreased speed, and eventually incomprehensibility.
Sensory testing may reveal deficits in pinprick, temperature, proprioception, or vibration. A sensory level may be evident.
Manual muscle testing can show varying degrees of muscle weakness. The patient may exhibit poor control of a limb or insufficient clearance of the foot during gait. Spastic gait may be another motor finding. Cerebellar involvement may be manifested as dysmetria with past pointing on finger to nose testing and uncoordinated heel to shin movements. The Ashworth Scale (or Modified Ashworth Scale) [23] is commonly used to measure the amount of spasticity, and the 88-item Multiple Sclerosis Spasticity Scale is a reliable and valid measure of the impact of spasticity in patients with MS [24].
