Diagnostic tests
There are no definitive diagnostic tests for either CFS or MS but because MRI tests are commonly ordered, there are some
subtle differences practitioners can look for. In CFS patients, MRI studies may reveal areas of increased signal intensity in the white matter of the central nervous system (CNS), which are generally punctate rather than ovoid in size and are scattered throughout the white matter, usually at the periphery near the white-gray junction. In MS patients, increased signal intensity in the white matter of the CNS is usually found in the periventricular areas.

Changes in cerbrospinal fluid have also been reported in CFS patients, such as leukocytosis, elevated IgG synthesis and oligoclonal bands in a very few patients.²
Consequently, practitioners must not rely on MRI findings alone for patients diagnosed with MS, but consider the patient history and the neurological examination.

Symptoms
Although CFS can often present in the same manner as MS, there are many differentiating symptoms, including neurological,
cardiovascular, gastroin-testinal, autonomic and muscular conditions.

Neurological signs and symptoms. Neurological signs and symptoms are rare in CFS. Henderson and Shelokov found signs of paresis, diplopia, urinary retention, facial paresis and the Babinski’s sign in their review of patients involved in recorded outbreaks of CFS.³ Komaroff and Buchwald also reported seeing ataxia, focal weakness and transient blindness in CFS patients.^4,5

Although these symptoms are also found in MS patients, Babinski’s sign, paresis or paralysis are much more common in MS patients, as are gait disturbances, foot drop and a “pins and needles” numbness.

On the other hand, some neurologists have found no neurological abnormalities in their CFS patients.^6,7,8 This may be due to the fact that neurological symptoms in CFS patients don’t always have a set pattern. As at least one researcher noted, “A [CFS] patient examined in the morning might have nystagmus, which would disappear at midday, recur later, disappear again and recur the next day. This on-again, off-again pattern is typical of CFS.”⁹

MS and CFS patients will both complain of feel-ing dizzy or lightheaded.  MS patients experience nonpositional vertigo and ataxia, losing their balance on the Romberg test, but CFS patients do not have true ataxia. Rather, CFS patients experience a sensa-tion of disequilibrium. They may also have orthostatic intolerance or syncope. CFS patients will report ringing in the ears and headaches, which is also uncommon in MS patients.

Neurological symptoms that are rare in CFS patients but typically occur in MS patients include monocular color blindness, hemifacial spasms, gait ataxia, optic/retrobulbar neuritis, unilat-eral intention tremor, scanning speech, binocular diplopia, trigeminal neuralgia, monoparesis and transverse myelitis.

MS patients rarely report cognitive problems, but cognitive problems are common in CFS patients, usually manifesting as impaired memory or concentration or information processing difficulties, often described as “brain fog.”

Muscular pain and sensations. CFS patients often complain of pain. Acheson emphasized that “pain, invariably present, may be devastating and is perhaps the feature that impresses itself most forcibly on the observer.”¹⁰ Muscle pains are not part of the clinical picture of MS, however.

Most CFS patients will also experience migratory paresthesiae, often with a painful burning sensation that moves from one part of the body to another within a matter of hours or days. MS patients do not experience migratory arthralgias or joint pains.

Medication responses. CFS patients often have paradoxical or unusual reactions to even low doses of medications, but MS patients don’t. Most of the symptoms of CFS do not respond to corticosteroids, used to reduce the severity of MS relapses.

Other symptoms. Gastrointestinal symptoms such as irritable bowel syndrome, nausea, vomiting and diarrhea are common in CFS patients. MS patients, however, more frequently experience bowel retention or incontinence. Cardiovascular problems in CFS patients include increased orthostatic blood pressure and rapid pulse. General weakness and post-exertional malaise and fatigue are also very common in both CFS and MS patients. CFS patients often experience fevers, chills and sore throat at the onset of their illness, characteristics that are extremely unusual in MS patients.

Clinical Suggestions
Enough differences exist between CFS and MS that clinicians should first conduct an exhaustive patient history and examine all signs and symptoms. The combination of fatigue, two of the major and two of the minor symptoms is strongly suggestive of the diagnosis of CFS (see Table 1 below).

Patients and health care practitioners could better serve patients by not accepting an MS diagnosis based on MRI findings alone. Many MRIs are interpreted by radiologists who are not adequately trained to differentiate white matter abnormalities that may mimic MS. Further, many neurologists often fail to obtain a complete patient history or even view the actual MRI film, which is sometimes incorrectly interpreted by radiologists.

References

1. Poser C et al. Ann Neurol. 1983; 13: 227-231.
2. Warner C et al. Neurology 1989; 39 (1):420.
3. Henderson D et al NEJM 1959; 260: 757-764.
4. Komaroff A in Hyde D (ed.) The clinical and scientific basis of myalgic encephalomyelitis/chronic fatigue syndrome. The Nightingale Research Foundation, Ottawa, Ont. Canada. 1992: 228-34.
5. Buchwald D et al. Ann Int Med 1992; 116:103-113.
6. Lane R in Hyde D (ed.) The clinical and scientific basis of myalgic encephalomyelitis/chronic fatigue syndrome. The Nightingale Research Foundation, Ottawa, Ont. Canada. 1992: 395-9.
7. Behan P et al. J Infect 1985; 10: 211-22.
8. Buchwald D et al. JAMA 1987; 257: 2303-7.
9. Pellew R. Med J Austral 1951; 1: 944-6.
10. Acheson E. Am J Med 1959; 26: 569-95.

Major Symptoms

• Fatigue
• Migratory myalgias
• Migratory arthralgias
• Migratory painful paresthesiae
• Memory and cognitive disturbances