Ask the Doctor

Q: My question is about the animal model for MS, often referred to as EAE. Can you please explain exactly how researchers induce EAE in their experiments with mice?

A: Experimental allergic encephalomyelitis (EAE) is a complicated animal model that some scientists believe mimics MS. Many books have been written on the subject. Some EAE models exhibit relapsing forms of the MS-like condition in rodents.

EAE is produced by injecting myelin basic protein or a similar substance plus an immune-activating substance, "Freund's adjuvant," into animals (usually rodents). This leads to vigorous immune-mediated damage to the brain and spinal cord of the animals.

This MS model is used to screen potential therapies to treat MS. Some of these therapies have reduced or prevented EAE, and are then used in trials with humans. Unfortunately, the results are mixed, and some of the treatments that work for EAE do not help MS patients.

Q: My friend was diagnosed in her teens as having severe chronic fatigue syndrome (CFS). In her mid-thirties, the diagnosis was changed to MS. Because there is so much overlap between MS and CFS, including fatigue, neurological problems, and even similar brain irregularities when scanned, how does one know if a diagnosis is correct? Can CFS "turn into" MS?

A: Differentiating MS from CFS is often problematic, especially early in the disease process. This is true for other similar disorders as well, such as Lupus.

Usually MS occurs as specific attacks of neurological symptoms with objective findings that appear and disappear over a period of days, weeks, or months. CFS symptoms are usually less specific, with fatigue as the primary symptom, usually without objective neurological findings.

The MRI in MS is usually more involved and has lesions characteristic of MS. On the other hand, CFS MRI findings are more nonspecific and less numerous. CFS MRI findings are also less likely to enhance with dye (gadolinium). The results of a spinal tap are more often abnormal with MS than with CFS.

All of these are guidelines, but the diagnosis depends on a good neurological exam to put all of these findings into perspective. I usually recommend a second opinion from an MS center of excellence. As far as CFS "turning into" MS, I don't know of any studies to support this change. I would assume that in the case of your friend, her initial symptoms were perhaps more indicative of CFS, but as her symptoms progressed, a (correct) diagnosis of MS became more apparent.

Q: What might be the significance of one oligoclonal band in the spinal fluid?

A: Oligoclonal bands indicate abnormal antibody production, which occurs as part of the MS process. To help us in the diagnosis of MS, we anticipate at least two oligoclonal bands in the spinal fluid. I consider the finding of one band to be of interest - and such a finding might prompt a second spinal tap after several months, if the diagnosis was still in question.

A neurologist makes the diagnosis of MS based upon clinical evidence. While an MRI or spinal tap can help to confirm the physician's suspicions, a diagnosis is not made exclusively from the results of these two tests.

Q: I have been diagnosed with MS since 1994, at which time the diagnosis was based on my symptoms of imbalance, numbness of extremities, and optic neuritis; my MRI was normal then and in 1995. My MS neurologist hasn't suggested another MRI since then, and I'm afraid to get one because if it's normal, I may lose my disability, even though my imbalance prevents me from standing. Do you have any suggestions?

A: As mentioned in the response to the previous question, the diagnosis of MS is based on clinical evidence and not solely on the results of an MRI or spinal tap. With this in mind, the diagnosis of MS should not be changed based on a normal MRI, which occurs for approximately five percent of the MS population.

A more important question involves treatment. Most neurologists believe that patients with MS should be treated early in their disease. If your neurologist is not recommending treatment based on your normal MRI, then a second MRI may be very helpful to your doctor. If you fear that a second, normal MRI would jeopardize your disability status, then I recommend getting the MRI without notifying your insurance company. You need to decide if the added expense is worth the added gain, which is a discussion for you and your neurologist.

Jack Burks, MD, is a neurologist who specializes in MS. He is vice president & chief medical officer for MSAA, as well as president of the Multiple Sclerosis Alliance. Additionally, Dr. Burks is a clinical professor of medicine in neurology at the University of Nevada School of Medicine in Reno, Nevada, and a member of the Medical Advisory Board of the National MS Society. He has edited two textbooks on MS, and in the 1970s, Dr. Burks established the Rocky Mountain MS Center.

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