TABLE OF CONTENTS
Diagnosis of CFS and MS
By Dr. Charles M. Poser,
MD, FRCP (GLE)
Harvard Medical School
number of CFS patients are misdiagnosed with multiple sclerois (MS). The severity and symptoms of chronic
fatigue syndrome (CFS) fluctuate and sometimes mimic the relapses and remissions of MS. In addition, when
health care practitioners suspect a patient has MS, they almost always refer the patient to a neurologist,
who then sends them for magnetic resonance imaging (MRI) testing. Today, unusual cerebral white matter
on MRI tests often automatically leads to the diagnosis of MS.
In a review of 366 patients referred
to me who had been diagnosed with MS by a board-certified neurologist, only 236 patients (65%) had been
correctly diagnosed. An astounding 28 (22%) actually had CFS.1
The extent of the misdiagnosis
of MS is disturbing, particularly in light of the current therapeutic frenzy dictating the immediate initiation
of expensive, disease-modifying drugs of still unproven, long-term efficacy, such as interferon beta.
Further, no studies have been done to determine the short- and long-term effects of giving such drugs
to CFS patients, who may be incorrectly diagnosed with MS.
This article attempts to clarify the
neurological abnormalities and symptom presentations of both conditions because of this overreliance on
MRI testing and misinterpretation of MRI test results.
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
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
must not rely on MRI findings alone for patients diagnosed with MS, but consider the patient history and
the neurological examination.
Although CFS can often present
in the same manner as MS,
there are many differentiating symptoms, including neurological,
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.
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.”
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.
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.
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.
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.
Poser C et al. Ann Neurol. 1983; 13: 227-231.
Warner C et al. Neurology 1989; 39 (1):420.
Henderson D et al NEJM 1959; 260: 757-764.
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.
Buchwald D et al. Ann Int Med 1992; 116:103-113.
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.
Behan P et al. J Infect 1985; 10: 211-22.
Buchwald D et al. JAMA 1987; 257: 2303-7.
Pellew R. Med J Austral 1951; 1: 944-6.
Acheson E. Am J Med 1959; 26: 569-95.
Table 1: Clinical Characteristics of CFS
- Migratory myalgias
- Migratory arthralgias
- Migratory painful paresthesiae
- Memory and cognitive disturbances